If it is OK with the group, I'd like to chronicle my efforts to restore this motel salvage set. I've seen this done here, and quite honestly, the documented steps that others here have bothered to share was the catalyst for my decision to attempt a similar project. This first installment of photos were taken by the guy I bought the set from, so this is how it looked when it arrived at my P.O. Its a 59 Philco Predicta, Debutant model, 10L43 chassis. It was missing the back and power cord, but otherwise complete. It arrived with one small crack to the CRT cover, only visible from the top and won't effect viewing. It smells like hell, if Frank Sinatra were Satan.

http://i523.photobucket.com/albums/w353/chemo64/Predicta/1.jpg

http://i523.photobucket.com/albums/w353/chemo64/Predicta/3.jpg

http://i523.photobucket.com/albums/w353/chemo64/Predicta/2.jpg

Here is the chassis before I cleaned it. The whole shebang smells like its been sitting in a giant dirty ashtray for the last 40 years. And as a former smoker, I really, really hate that smell...:
http://i523.photobucket.com/albums/w353/chemo64/Predicta/chassis1.jpg

http://i523.photobucket.com/albums/w353/chemo64/Predicta/chassis2.jpg

And the ill fitting round speaker someone had installed. I've ordered a proper oblong 4 x 6.
http://i523.photobucket.com/albums/w353/chemo64/Predicta/speaker.jpg

Here is the chassis after I cleaned it with q-tips and alcohol (a technique I learned from here!). I tested the resistors and found 20 of them on the board and tuner that were out of tolerance! I've been attacking the rust, but still have a few places to address while I wait on the replacement parts to arrive.

http://i523.photobucket.com/albums/w353/chemo64/Predicta/Chassis3.jpg

Some of the metal parts after rust removal and polishing, but before priming and painting. I used an electrostatic rust removal process to attack the deepest rust spots, using a 6-volt power supply positive terminal connected to a piece of stainless steel, the negative connected to the part (both by-way of cheap alligator clips and some 16 gauge wire. The process pretty much destroys the clips). I used a plastic tub with a solution of salt (1 tbsp per gallon) and let the whole thing soak overnight connected to the power supply. It basically replaces oxidization with ferrous compounds from the stainless steel ~ think Dorian Gray!)

This is pic where I used this process on an old metal/porcelain caster:
http://i523.photobucket.com/albums/w353/chemo64/Predicta/Elect.jpg

Here are the parts:

http://i523.photobucket.com/albums/w353/chemo64/Predicta/Metalpartsbeforepainting.jpg

Wow...I can hardly wait to see more progress...Howzabout the caps ? I'm sure they were a disaster like the resistors were, too...You obviously Know What You're Doing...

Here are some of the parts after priming and painting. I used an aluminum-zinc paint trying to come close to the original tone and finish. Its OK, and since no one but me will ever bother looking inside the set, who really cares anyhow?

http://i523.photobucket.com/albums/w353/chemo64/Predicta/metalpartsafterpainting.jpg

Wow...I can hardly wait to see more progress...Howzabout the caps ? I'm sure they were a disaster like the resistors were, too...You obviously Know What You're Doing...

To be honest, I didn't even bother testing a single one of them. I just ordered the lot from Mouser and will replace all of them.

As for knowing what I am doing? Ha ha!!! Thanks for you kindness, but we'll just have to see what happens next! The only thing I really have going for me is that I am patient and won't rush this. Other than that, I plan to continue to pick you guys' brains for all that its worth! I've been tinkering with radios for 15 years or so, but this is my 1st television. And since most wise people say not to chose a Predicta for your first set, I'm a big enough dumb-sh!t to do exactly that. If it works out, there will be no living with me. If it blows up and maims or kills me, you guys will get a laugh. Either way, it should be entertaining. :thmbsp:

I'm entertained already just following your progress, good show. I've used that electrolytic rust-eater setup before but with "washing soda" (sodium carbonate) available at supermarkets. It really eats the rust off of some nasty cases.

I'm entertained already just following your progress, good show. I've used that electrolytic rust-eater setup before but with "washing soda" (sodium carbonate) available at supermarkets. It really eats the rust off of some nasty cases.

Thanks! Yeah, I tried the washing soda once too, but I really couldn't tell any difference from when I used salt. The salt is "kosher", so maybe that's what makes the difference :angel:

I did find that with either agent, you end up with a big ole bowl of yuck. I've been dumping it in my German neighbors flower bed since she continues to let her yappy little dog crap on my front stoop. I watched her looking at her 'rusty' marigolds in dismay yesterday afternoon. What a hoot.

are you planing to pull the main board to get at the bottom side? there are pros and cons

Pros:

allows careful inspection of solder joints and neat replacement of any bad parts, including tube sockets.

Cons:

there are a LOT of wires that are connected to it, and you have to unbend and desolder some big ground stakes.

My approach
On mine I Opted to take the do no harm approach. That is leave it as original as possible, remove as little as possible until I had a chance to evaluate the existing status. I did replace all paper caps and check the can caps. On mine the thin can cap next the the transformer was open. It was a low voltage can 2 section IIRC.

After that I pulled the HOT and did a slow power up with a variac looking for smoke and any signs of distress. checking for voltage drop at the B+ and checking the current.

Next I put in the HOT with an adpater to check the current, power up this time fast and I got raster and checked the current, all good.

then the signal to the tuner and another powr up this this time and its looking pretty good but for the brightness control, an open resistor was the culprit. that is about all it took.

I did have some tube socket issues, the vert out was intermittient, (line on screen, wiggle socket and it comes back) that needed to be replaced.

Also the HV would go away, turned out to be an intermittent damper tube, this time not the socket but a ground stake that completes the filament circuit.

I was able to get replace most of the paper caps with out removing the main board, I used solder braid and low watt iron. On some of the caps that had pads shielded by the chassis I used my solder gun and bent the tip 90 degrees to get at the pad. lots of care and braid to clean it up. Extemly easy to lift a pad this way so you need to go slow and never force a part down.


I was lucky I did not need to replace any other sockets as many are hard to get at and would most likely require pulling the board, but as I said do no harm.

Hi Dave,
I've thoroughly read through your restoration thread (several times). Yours was the one that convinced me that this was something I wanted to attempt.
As of now, after corresponding with Sonny "The Radiola Guy", I'm still planning on pulling the board. I am apprehensive (because of the 'cons' you listed), but I'm determined to nug through it.

I can't seem to find solder braid / wick here locally, but I did pick up a very nice German-made solder sucker, it is very long and very slender, about the diameter of a fat writing pen, with a nice long, slender point. It will reach into some pretty tight spaces. And I've got several thin 40W solder irons, as well as a big honkin' antique iron for soldering grounds to chassis, and a good old Weller gun.

I've tested the tubes, and all are OK except for the 6BZ7 on the tuner, which is gassy. Ordered the replacement from ETE tubes.

I am following your advise about powering up via Variac without the HOT, then again with it. I was lucky and learned about "just plug it in and see what happens" on my very 1st antique radio. A nice little inexpensive Admiral that went up in a cloud a acrid black smoke as the transformer turned into a skillet full of molten tar.

I definitely don't want to do any harm, but from the looks of this chassis, it has been the victim of a motel TV repairman's 'gitter-done' attentions, so I'm not taking any chances. I'm just replacing all caps & electrolytics, and touching-up every solder point.

I offer these two pics to support my idea of Motel Joe's hack job:
http://i523.photobucket.com/albums/w353/chemo64/Predicta/crappy1.jpg

and this:
http://i523.photobucket.com/albums/w353/chemo64/Predicta/crappy2.jpg
I don't know, since I've never seen one, but this CAN'T be a fused resistor, can it?

Since I don't have a television signal generator, I intend to use a VCR for the signal. Is this an OK idea, or worthless?

wow, some one has been re-engineering that one. Not sure what the heck the big sand resistor tack on is for. Yea the fusistor is gone. I have a fusistor in mine, but if it ever goes my plan is to replace it with a 10 ohm power resistor,1/2 amp fast blow fuse and maybe a thermistor to soft the blow on startup.

Hopfully your deflection control pots are ok. I would not mess with them, just hope they are in the right spot. some of them are wirewounds and I had one that was toast, wire busted inside, all cruchy etc.


I do like predictas the module approact make them easy to work on.

I ordered a replacement fused resistor, sight unseen, so I'll let you know what I actually get.
As for that sand resistor, its grounded to the corner lug on the board and hooked to the Vert LIN post. Two 10W 2K resistors in parallel. I can't even imagine.

ah, prob replaced the aforementioned wire pot with one that did not have a built in internal stop that limits the throw of the pot. the orig pot is like buzz pot with a built in stop that limits the travel and maintains a min resistance for the cathode to ground which sets the tube bias.

Here is the chassis after I cleaned it with q-tips and alcohol (a technique I learned from here!). I tested the resistors and found 20 of them on the board and tuner that were out of tolerance! I've been attacking the rust, but still have a few places to address while I wait on the replacement parts to arrive.

http://i523.photobucket.com/albums/w353/chemo64/Predicta/Chassis3.jpg


something about that pot on the extrerm right does not look right, Although the mounting arangement seems correct for the type of pot used. Odd. just a guess but the resistor is prob a higher than called for value and the pot is lower than called for. that way less voltage drop across the pot so a lower wattage pot would work (but the range would suffer as well so the fixed resistor would have to be pretty close to the correct total required value).

the lin pot calls for a 1500 ohm with an internal stope at 180 ohms.

Curiosity killed the cat & all, but...Did you find this Predicta there in Germany, or did you ship it in from America ? If that was the case, I bet it set you back a small fortune in shipping charges...An' you're lucky it got there in 2 big pieces...(grin)

Curiosity killed the cat & all, but...Did you find this Predicta there in Germany, or did you ship it in from America ? If that was the case, I bet it set you back a small fortune in shipping charges...An' you're lucky it got there in 2 big pieces...(grin)

I bought it from a guy in the States. I paid peanuts for the tele, but he swindled me on the postage (paid for priority x 2 boxes (each double boxed). He sent 2 boxes via parcel post (painfully slow and rough handling) and single boxed them. So I forked out about $100 for postage, and he spent about $55. Chiseler.
I guess I am lucky that there was only one small crack in the CRT cover. Could have been a lot worse.

the lin pot calls for a 1500 ohm with an internal stope at 180 ohms.

Good catch. I hadn't even noticed that oddball until you pointed it out, (and the plastic insulated wire should have been the dead give away).
Its a flippin .5 MEG pot at 2W.
Sheesh, I'll order a proper pot when I order the resistors tonight.
Good news is that the caps arrived today.

half meg? geez there must have been a super critical adj. check check the tube resisitance on pin 9 of the 6dr7 vert out tube to ground. Should be around 450 ohms, give the meter a chance to settle in as there is a bypass cap across it. It must be set to nearly fully closed (min resistance).

C3 that bypasses it will most likely be open, it sets next to the Pwr tranny and gets baked, dries out, at least that was the case on two predictas I worked on.

Since I don't have a television signal generator, I intend to use a VCR for the signal. Is this an OK idea, or worthless?
If you just want to check operating voltages or eyeball things, a VCR signal is as good as any. To adjust things like linearity & centering, it's better to use a pattern generator that will give you a crosshatch pattern, cross, dots, etc. B & K made some Dynascan generators (1230, 1245, etc.) that are small enough to hold in your hand and often sell very cheap on eBay. Search for "color generator" or "pattern generator." For test gear like this, I'd generally avoid a vintage device, which will need the same kind of service as any old tube equipment and may also need calibration that you're not equipped for.

Phil

I've got a question about the electrolytics. I've read where certain sections of these TVs require exact component replacements. I had to go with a little higher rated caps on two stages on the 4-stage E1, and the single stage E1. The original ratings were 80mf at 350v (I used 82mf at 450v), and the other two were both 200mf at 150v (I used a 220mf at 160v). Are these eletrolytic stages required to be exact, or will the ones I have listed work?

The caps you listed will work. The difference in value is probably equal to or less than the manufacturing tolerance, in any case.

It's generally OK to go somewhat higher in capacitance with electrolytics, but don't go nuts. Don't substitute 100mfd for 22mfd, for instance. There's no advantage to using the 100mfd cap and it will be larger/more expensive.

Ditto with voltage ratings.

Phil Nelson

The caps you listed will work. The difference in value is probably equal to or less than the manufacturing tolerance, in any case.

It's generally OK to go somewhat higher in capacitance with electrolytics, but don't go nuts. Don't substitute 100mfd for 22mfd, for instance. There's no advantage to using the 100mfd cap and it will be larger/more expensive.

Ditto with voltage ratings.

Phil Nelson

Thanks Phil. That's the procedure I normally follow with radios, but I had read somewhere that at least one section of these Predicta's requires exact value replacements. But I can't seem to find that website now, and I can't remember which section nor exactly which capacitors where involved. Dang!

If you just want to check operating voltages or eyeball things, a VCR signal is as good as any. To adjust things like linearity & centering, it's better to use a pattern generator that will give you a crosshatch pattern, cross, dots, etc. B & K made some Dynascan generators (1230, 1245, etc.) that are small enough to hold in your hand and often sell very cheap on eBay. Search for "color generator" or "pattern generator." For test gear like this, I'd generally avoid a vintage device, which will need the same kind of service as any old tube equipment and may also need calibration that you're not equipped for.

Phil

I found a post tonight where a guy described using a test pattern card that he printed, taped to a wall and shot with his video camera. He then fed his video camera into the television he was working on. Sounds like a pretty simple 'poor boy' solution. Not the perfect solution, but perhaps good enough?

If you just want to check operating voltages or eyeball things, a VCR signal is as good as any. To adjust things like linearity & centering, it's better to use a pattern generator that will give you a crosshatch pattern, cross, dots, etc. B & K made some Dynascan generators (1230, 1245, etc.) that are small enough to hold in your hand and often sell very cheap on eBay. Search for "color generator" or "pattern generator." For test gear like this, I'd generally avoid a vintage device, which will need the same kind of service as any old tube equipment and may also need calibration that you're not equipped for.

Phil

OK, I said the heck with it and bought a Dynascan 1245 from a guy on eBay for 10 bucks. I hope it actually works...

Sounds like a pretty simple 'poor boy' solution.
Caught red-handed! That was my po' boy solution when I did my Predicta 1,000 years ago and didn't own a pattern generator. I had forgotten all about that scheme until you mentioned it.

http://antiqueradio.org/philc12.htm

Phil

Caught red-handed! That was my po' boy solution when I did my Predicta 1,000 years ago and didn't own a pattern generator. I had forgotten all about that scheme until you mentioned it.

http://antiqueradio.org/philc12.htm

Phil

That is great Stuff! You're a legend, Phil (AKA Phil's Old Radios)
I love reading about your projects! I don't how many people you've helped, but you've sure helped me! Thanks. :thmbsp:

I'm trying to replicate the control labels on the back of the cabinet top. It dawned on me that someone here might know the font that Philco used on these sets? Here's what I've got, so far. It isn't exact, but I'm rapidly losing concern about it...

http://i523.photobucket.com/albums/w353/chemo64/Predicta/Text1.jpg
This is Haettenschweiler 24 font size with a 4 point character spacing.

half meg? geez there must have been a super critical adj. check check the tube resisitance on pin 9 of the 6dr7 vert out tube to ground. Should be around 450 ohms, give the meter a chance to settle in as there is a bypass cap across it. It must be set to nearly fully closed (min resistance).

It settled in to a steady 940 ohms. And when you say "It must be set to nearly fully closed" You are talking about the Vert Lin pot? If so, it made no difference to the reading, no matter where I set the pot.

C3 that bypasses it will most likely be open, it sets next to the Pwr tranny and gets baked, dries out, at least that was the case on two predictas I worked on.

I'm not sure I understand you. I see C3 as a ceramic cap up on the video IF board. The only cap I see near the P.T. is C41, a .047 line bypass?

It settled in to a steady 940 ohms. And when you say "It must be set to nearly fully closed" You are talking about the Vert Lin pot? If so, it made no difference to the reading, no matter where I set the pot.

interesting, that pin is supposed to be connected to the pot, so I assumed it should have done something. See if you can trace the pot to a tube pin.

I'm not sure I understand you. I see C3 as a ceramic cap up on the video IF board. The only cap I see near the P.T. is C41, a .047 line bypass?

I am looking at the SAMs, C3 section A is one of the electros that bypasses the cathode of the 6DR7. The sams and the notes printed on the PC board do not match up. See if you can find a wire from the thin can (low volt 100mfd) going to the pin 9 of the 6DR7 (or to the pot that connects to that pin).

I am looking at the SAMs, C3 section A is one of the electros that bypasses the cathode of the 6DR7. The sams and the notes printed on the PC board do not match up. See if you can find a wire from the thin can (low volt 100mfd) going to the pin 9 of the 6DR7 (or to the pot that connects to that pin).

AH, OK got it. Its labeled as E1 section 3 (100 mfd at 50v) and yes it is right up against the P.T., and yes it is open! (and so are the other two sections). I already have all electrolytic and cap replacements on-hand. I'm not going to re-stuff this can, but mount the new e-caps on the board. Heck the wire that connects that cap to the vert lin post runs a full 3/4 length around the board!

interesting, that pin is supposed to be connected to the pot, so I assumed it should have done something. See if you can trace the pot to a tube pin.

I don't know what this pot is for now.
I traced the pot to a wire connected a lead for the 400v B+ that jumps over to the that same e-can, hooked to the 10 mfd 450v?

hmmm, maybe some kind of rigged up focus control. need more can you tell where each lead goes and I will see if I can find out whats going on. the Lin pot is a cathode bias pot, pin 9 to ground.

I'm trying to replicate the control labels on the back of the cabinet top. It dawned on me that someone here might know the font that Philco used on these sets? Here's what I've got, so far. It isn't exact, but I'm rapidly losing concern about it...

http://i523.photobucket.com/albums/w353/chemo64/Predicta/Text1.jpg
This is Haettenschweiler 24 font size with a 4 point character spacing.

Another close-fitting font is Alternate Gothic No. 2.

ok duh, its the height pot, schematic say 3 meg pot. Still dont get the big resistor, it should be connected to a 1.5 meg resistor that goes to the plate of the 6DR7

check the resistance of pin 6 to the 275v source should be around 3.9 meg

what is the value of that big sand resistor tacked on?

hmmm, maybe some kind of rigged up focus control. need more can you tell where each lead goes and I will see if I can find out whats going on. the Lin pot is a cathode bias pot, pin 9 to ground.

OK, I traced the two leads coming from the pot. Black goes to ground, red to the post marked "B+ 400 2" the orange and white wire jumps it to another post, then to the electrolytic as described previously. The circuit board path, I outlined with the red line, takes it to pin 9 on the audio out tube, 6BQ5.
Huh?
Tone control, maybe? I thought this might be an audio pot, at least it is similar to tone control pots I've seen in old tube amps.
I really don't know.
Let me know if this picture helps, or if you need me to take some other detailed shots.
http://i523.photobucket.com/albums/w353/chemo64/Predicta/trace1.jpg

Another close-fitting font is Alternate Gothic No. 2.

I don't have selection in Power Point. Could you send me an example?

what is the value of that big sand resistor tacked on?

Even though it is two 2K resistors connected in parallel, the resistance only measures at 939 ohms.

check the resistance of pin 6 to the 275v source should be around 3.9 meg

If you mean the 275 from the VOT, I can't get a good reading. It starts around 18M and climbs beyond what my VOM can handle. Or should I be checking from another location?

it looks like the lin pot was taken out of circuit and replaced with a fixed resistor (the big sand resistor). This would be confirmed by no change in resistance from pin 9 to ground when adjusting the Lin pot (not the big round one it sould be a little trim pot marked lin adj). So you would be stuck with what ever the lineaity is (no way to adj) which may be ok.

the big round pot looks like a height adj. you should see a 275 marked pin on the side of the board, I think I can make that out. But to be sure you can check the output from the filter choke, that is also 275v. see if the resistance is 0 at that 275 pin when comparing to the output side of the choke, then you know its the right one.

The 275v source is used in several of the pin resistance measurements (as well as ground of course).

again you dont want to make a lot of changes until after a base line run, I just ran into that when working on a color set. was working with a bit of snow, I pulled the chassis, cleaned the tuner, then checked tubes, replaced a couple out of spec parts and end up with no snow, but sync and color problems. turned out to be some of the new tubes as I put the old ones back in and problems went away. My hickok tube tester showed the old tubes as weak and the nos tubes as much better.

I would try to limit myself to just replacing the papers, and bad eletros, do a base line run to see where you are, then make one fix at a time.

Resistance and voltage measurements can be helpful but do not aways tell the whole problem.

OK, so I'll let this thread rest a bit while I work the board loose from the chassis and start swapping caps, electros and resistors, and nailing down cold solder joints. Its going to take me a bit since we've got some events coming up. I'll try to pop up a picture or two when I make some progress.

I did want to report that I have definately decided to pull the main board. I replaced 4 caps last night in and around the audio section, since they appeared to be 'low hanging fruit". But even these fairly accessible caps weren't "a snap".
I won't actually pull the board, just "loosen it up", meaning I'll free it from the grounding stakes, but leave the wires connected. I calculate that I'll be able to lift the board about 5-6 inches away from the chassis. That should allow me easier access to most everything.

BTW, I finally found some solder braid at a different hardware store yesterday, yippee! They even had the HCL I was needing to etch some PCBs I'm building, and the water-soluble temporary spray adhesive for neat decal -pressure transfer system I'm putting together (for the control text on the back of this cabinet, as well as a good looking substitution for the silk-screened, reverse painted dial scale which is broken from my 1936 Blaupunkt KW741!)

On a related topic, I see that the previous repairman did not concern himself with lead dress. The Philco Service Manual dedicated an entire page to lead dress, so I suppose it is important enough to follow thier recommendations. I'll re-do the ones that are suspect.

I do see why people recommend NOT choosing a Predicta for you first tv restoration. I am having a blast though, and suprising enough, my wife remains positive about the whole project.
So, for today: Life, 'tis good!

the key is not to rush it, hopefully you will only have to fix the predicta once, and I can tell you have the right attitude for it. I used to just enjoy getting a couple caps done. Its a big difference when you are in it for fun vs. profit.

I wasn't able to devote much time this weekend to the chassis, although I spent a little time on the grille and cabinet (just to get it out of the living room!). I stripped the cabinet down to bare metal using paint remover and a wire brush wheel on my drill. There was a bit more rust that I realized, so I dabbed on some rust remover, then more wire brush action. The grille came out pretty good, using the blue/silver/black metalized cloth (for some Fender amp) I bought from Mojo. Since I had the original cloth to use as a guide, cutting the replacement was simple.
Before:
http://i523.photobucket.com/albums/w353/chemo64/Predicta/grilleclothbefore.jpg

After:
http://i523.photobucket.com/albums/w353/chemo64/Predicta/grilleclothafter.jpg

I still have to clean up the corners...
I used fabric from a white linen napkin to cover the speaker hole prior to mounting the grill cloth and painted the masonite board a matte finish white. This made the hole invisible and the white brings out the silver threads very well.

Looking good :thmbsp:

One thing I noticed the first time I ever worked on a Predicta- all the point to point wiring is light gauge single strand wire which will break at the solder joint if it's moved too often. And who knows how much manipulation it had before you touched it ?

Pallophotophone

One thing I noticed the first time I ever worked on a Predicta- all the point to point wiring is light gauge single strand wire which will break at the solder joint if it's moved too often. And who knows how much manipulation it had before you touched it ?

Pallophotophone

Thank you for the tip. Just to get an idea, I tested one suspicious looking lead, and you are right on the money. It snapped right at the insulation after only two bends. I think I will go ahead a redo all of the 'iffy' ones, snipping the wire, and stripping out some 'fresh' wire for the lead dress.

Last night, I freed all of the grounding points that hold the main board in place, and after removing the pots and freeing the V.O.T. from its mounting position, I was able to lift the board up plenty high enough to get to everything underneath with ease. I also was able to burn the snot out of my right hand ring finger with the soldering iron.
Its not a good idea for me to try left-handed soldering, I found out.

So replacing the remaining caps has become quite easy. Hopefully the resistors will arrive today or the next. We're gone for a week starting this weekend, so I'd like to make some headway before then.

Also, I am now a huge fan of Novus plastic polish (3,2 and 1). I was amazed at how many scratches on the CRT cover I was able to 'erase' using this system. I assume the 'smokey' tinting in the CRT cover is intentional, No?

And I tested a spot on the receiver frame using Simichrome paste. Wow, shined up in nothing flat. I'll finish up these cosmetics after I complete the board, or when I just need a break. I also find it simple to do these polishing tasks while watching a movie...

Patiently waiting for my "new" CRT tester and "new" pattern generator to arrive. And when I say patiently, I mean cussing the USPS and pacing a lot.

Not much time tonight, only replaced 5 caps and drew up my plans for decapitating the multi-stage electro can for re-stuffing. The wife just informed me that we'll be finishing her 'project' of cleaning out the basement tomorrow evening, so I don't expect much progress tomorrow either...

Also realized that Mouser short-changed me on a .047mF 400v and a .22mF 400v. Fortunately, I had both of those in stock already.

Finished off the last of the filter caps tonight, and will try to squeeze in some e-cap stuffing before we take off for a week. Tonight I also ordered a complete set of the J (or sometimes referred to a "K") networks from that guy at wadicta TV. A bit pricey, but I rahter pay for some good NOS ones than monkey around building replacements. I'll save that kind of work for when now replacements are available.

And Pallophotophone you were right, since I freed up the board and was wiggling it around so much, I managed to snap 3 different wires off. The connections were quite fragile, so I am glad they broke at this stage. They are secure now.

Since E3 is such a slender multi-stage, I decided to see what mounting the replacements directly to the MB would look like. They are in place. I hate it.
So, I am looking for alternative solutions/locations. (still no resistors yet)

http://i523.photobucket.com/albums/w353/chemo64/Predicta/recappedmainboard.jpg

Also, my "new" BK 465 arrived yesterday. With schoolboy haste I tore it out of the box, ran up stairs, gave it the once-over, looked up the settings for a 17DAP4, connected the appropriate adapter and fired it up. It powered on, allowed me to set the heater voltage, but nothing else registered. So, I calmed down, disconnected everything and gave it a closer inspection. While it appeared almost new, I now saw that the main connector had a chunk missing and that the red wire that should be connected to pin 1 was snipped away close to the outer insulation jacket. One small piece of solid core wire, a little heat shrink and solder, and the 465 was back in business.
http://i523.photobucket.com/albums/w353/chemo64/Predicta/BK465.jpg


Now that everthing was working correctly, I ran through the tests. No shorts, but low emissions. OK, so I give the rejuve feature a try. A *POP* sound that nearly made me piss my pants. I'm thinking, "OH NO!", What the...?" But, all is well as the tube now reads very good in the emissions test. PHEW! It showed on the low side of the cutoff voltage, but within the listed parameters (28v)

So, now I think it will sit and wait for the resistors to arrive. We are off this weekend to watch the Passion Play in Oberammergau. :banana:

Your board looks good. On mine, I pulled the whole thing, replaced every single cap and resistor (which is excessive, I know) hooked it all back up, and powered it up. The set ran like new!

I probably would not have rejuvinated that tube-I typically set the heater voltage a little higher, about 8 volts, and then let the tester cook away at the tube for a few hours. The emission almost always goes up. Rejuvination is very hard on crts (on all but the most expensive testers, it is usually just a fat cap discharging itself into the crt gun) and in some cases will totally trash a perfectly fine crt.

I restuffed my slender Ecap, just like to keep the lead dress as orig as possible.

Your board looks good. On mine, I pulled the whole thing, replaced every single cap and resistor (which is excessive, I know) hooked it all back up, and powered it up. The set ran like new!

I probably would not have rejuvinated that tube-I typically set the heater voltage a little higher, about 8 volts, and then let the tester cook away at the tube for a few hours. The emission almost always goes up. Rejuvination is very hard on crts (on all but the most expensive testers, it is usually just a fat cap discharging itself into the crt gun) and in some cases will totally trash a perfectly fine crt.

I guess I should count myself as fortunate. I won't be so hasty in the future. That "pop" made me come to my senses, and I won't soon forget it.

I restuffed my slender Ecap, just like to keep the lead dress as orig as possible.

I think I'm going to yank those 3 e-caps, replace the leads and stuff the can too.
It just looks messy. I may have to buy some different caps as I don't think these 3 will all fit inside the can. We'll see...

I always get radials, beside cheaper they fit better. Nichecon make some very slim ones that make for an easy fit.

I probably would not have rejuvinated that tube-I typically set the heater voltage a little higher, about 8 volts, and then let the tester cook away at the tube for a few hours. The emission almost always goes up. Rejuvination is very hard on crts (on all but the most expensive testers, it is usually just a fat cap discharging itself into the crt gun) and in some cases will totally trash a perfectly fine crt.

I second that, but these CRTs only run on 2.68 volts, so maybe 4-5 volts would be better ?

So, I went with a compromise. I moved the electrolytic replacements for E3 off of the MB.
http://i523.photobucket.com/albums/w353/chemo64/Predicta/removed.jpg

But instead of trying to re-stuff that slender can, I mounted them to a bus bar.

http://i523.photobucket.com/albums/w353/chemo64/Predicta/electrobus.jpg

I'll give this a try, and if I decide I just can't live with it, I'll order some radials and restuff the can.
I am re-stuffing the larger 4-stage E1 can.

I did score a set of the decorative arms and a new replacement cord.
http://i523.photobucket.com/albums/w353/chemo64/Predicta/armsandcord.jpg

The arms have two small posts intended to lock them in place on the base.
http://i523.photobucket.com/albums/w353/chemo64/Predicta/arm.jpg


So, now I'll have to drill a pair of small notched holes on the CRT mounting base.
http://i523.photobucket.com/albums/w353/chemo64/Predicta/armhole.jpg

Just a thought, its your set, but adding arms to a set that did not have them originally may make it less collectable.

Just a thought, its your set, but adding arms to a set that did not have them originally may make it less collectable.

Yes, that occurred to me as well. Two factors swayed my decision: 1) I found several precedence of the same model with these arms, leading me to to believe you could purchase this option. 2) Greatly enhances the WAF :D

I'm already completely unfaithful to the paint and grille cloth, and since I've no intention of parting with it for the foreseeable future, I'm OK with it.

Eh, I've been thinking about what you said about the arms for most of the evening. I believe I'll hold off on the drilling. Maybe I'll hang onto the arms for my next Predicta.

I was able the replace the antenna using an original mount (with only one remaining antenna section) and a replacement antenna of similar size. I really had to man-handle the mount to get it open so I could remove the ball and single section, and replace it with the donor. It took a bit of sanding and soft scrub to remove the chrome (so the gold plating would 'stick'). The first session of gold plating turned out about 75%. Once we get back home later in the week I'll attack it again and see if I can get more plating to adhere. Its looking really good so far.

Hopefully the resistors will be here too...

nice with the antenna, most I have seen (including mine) are pretty rusty around teh base, but the rest of my antenna is good.

Yes holding on to the arms for the next one is a good idea, as most have very rusty arms, and lots of pitting.

Granted this has absolutely nothing to do with this thread (or the entire forum, for that matter) but this is why I am on pause with the Predicta project:
http://i523.photobucket.com/albums/w353/chemo64/Germany/Oberammergau.jpg

View from our gasthaus window, Gasthaus zum Fischerwirt. We're here to see the Oberammergau Passionspiele (Passion Play) that's been acted out here more or less regularly since 1633. The play starts in 4 hours, so I'd better get going!

I finished replacing all remaining components tonight. Here's a photo of the finished main board:
http://i523.photobucket.com/albums/w353/chemo64/Predicta/FinishedMB.jpg

Nice job :thmbsp: I notice you left the old couplates in. I've heard some guys rebuild them. I just picked up a Predicta and it's running fine with the originals. I wonder how prone they are to failure :scratch2:

So, I plugged it in, said a prayer, turned it on, held my breath, and it slowly started coming to life....
sort of.

All I got was a single white horizontal line across the screen. And after about 30 seconds or so, I saw and heard a static discharge coming from the cheesy crimp connector on the HV wire, arcing to the chassis. It scared the crap out of me, so I turned it off.
Since its a vertical field problem, I'm thinking I've got a bad solder joint. Not sure what to do about that HV wire connector though...

Nice job :thmbsp: I notice you left the old couplates in. I've heard some guys rebuild them. I just picked up a Predicta and it's running fine with the originals. I wonder how prone they are to failure :scratch2:

I bought a complete set of good used ones from Ross Marshall, just in case.

1st turn the brightness all the way down, and check the 220k resistor that goes to the brightness grid on the CRT to make sure it is not open.

Predictas are known for bad tube sockets, if the vert tube is lighting up, then try it while wiggling the tube around.

Check the primary of the vert out transformer.

check the pin resistance of the 6DR7 tube to the sams values

425 to the 275v
2.1 meg to ground
2.1 meg to ground
.1 to ground
0 to ground
3.5 meg to the 275v will vary depend on control setting
68k to ground
50k to ground will vary depne on control setting
450 to ground will vary depending on setting
1000 to ground



Check voltages at the tube pins, this is where a socket extender comes in handy.

I wonder how prone they are to failure
I think the answer is "sort of." My understanding is that the capacitors inside are paper. I replaced one (K4) preemptively on my Predicta, having been told it was a troublemaker. The others are working fine, 10-odd years later.

Some folks replace all of 'em, some folks replace none. I guess I would consider [A] how well your set's working now, [B] whether you plan to do other work requiring removal of the big PC board, and [C] how much you hate the idea of possibly removing the board only to replace a failed couplate.

How's that for not really answering your question :)

Phil

...

If they're all ceramic, maybe I should change my thinking. How did you check the resistors before digging them out? (Asked another way, would it have been less work to make a new one?)

Phil

I think I need to address the electrical discharge issue before I go any further. In my best estimate, it appears to be emitting from the crimp connector on the HV. It arcs to wherever on the chassis with a loud 'pop' starting about 30 seconds after power up, then pops about ever 5 - 10 seconds. I'm not sticking my hand in there until I can fix this. I got struck by lightening in 1986, and I don't care to relive the experience.
Does this problem sound familiar to anyone? (the discharge problem, not the getting struck by lightening problem)

not sure where the crimp connector is, but have nver had a pop sound.

you could try backing off on the horz width control/and checking the hot cathode current.

I was going to ask what you mean by "crimp connector," but Dave beat me to it. Perhaps you could call it out on one of the pictures you have posted.

If you power it up with all the room lights off and watch carefully, can you see the arc?

Phil

Its here:
http://i523.photobucket.com/albums/w353/chemo64/Predicta/crimp.jpg

I'll try it in the dark and let you know about the spark.

most have been a way to make leaving the anode to the pic left and just disconnect there when removing the head.

good idea if it works. I would clean around that connector and wire, and dress it differently and see if that does it. my gess is the connector is getting close to the cage and the plastic is not rated for HV.

Maybe a cardboard doughnut near that to make sure it does not get next to the cage?

Now it behaves differently, and I suspect I was incorrect at where the pop was coming from. This time when I turned it on, I made note that each and every tube was glowing. None of them were going nuts, but they were definitely glowing, including the 6DR7. Wiggling the tube made no difference. I heard a little sizzling going on, and I tracked it to the underside of the board under the damper socket (6DA4) either under pin 2 or 3. It was just a small white spark dancing on top of that solder joint. I'll have to pull the board again to get a better look as that area is covered and difficult to see.
This time there was no activity on the CRT until I turned it off, and the line would appear for a second and disolve to a single point, center screen for 10 seconds or so.

check the pin voltages at the crt pin 2,3 and 7 if the CRT

sounds like it is cutoff.

I used an electrostatic rust removal process to attack the deepest rust spots, using a 6-volt power supply
I meant to ask this question when you posted the photos, but better late than never.

What did you use as a power supply? I have an old trickle charger that I used to recharge my motorcycle battery each spring. Maybe that would work.

Those pieces looked so good after the electrolytic process was done, I'm wondering why you then went on to paint them. Did they still have pitting where rust used to be?

Phil Nelson

I meant to ask this question when you posted the photos, but better late than never.

What did you use as a power supply? I have an old trickle charger that I used to recharge my motorcycle battery each spring. Maybe that would work.

Those pieces looked so good after the electrolytic process was done, I'm wondering why you then went on to paint them. Did they still have pitting where rust used to be?

Phil Nelson

That is exactly what I used, a 6-volt trickle charger; hooked the leads to a short length of wire attached to some super-cheap copper alligator clips (since they get destroyed in the process). I went ahead and primed and painted the pieces because I've found that even though the rust is removed/replaced, the 'aged' spots will quickly rust again with a vengeance. There was some pitting, but that was there before the process. Typically, whatever is present stays in place and will be replaced by the ferrous compounds. If the rust has left pits, it will remain pitted.

On an aside, years ago I found an 18th century toy gun outside of a castle in Rhineland-Pfalz. It was a rusted ball, that I thought was an actual gun. I worked on that thing for weeks, electro-bath, dental pick, again and again. After a few days, it was clean enough to recognize as a toy gun. Finally, I was able to free up the firing mechanism. I've been a believer in this process ever since.

OK, so its time for a break. I need to walk away from this thing for a few days before I hurl it out the third floor window. I have not been able to track down exactly where the problem(s) is (are). I think a breather will do me good.

We're driving over to the Normandy region of France on Monday for the D-Day remembrance activities. Last year I had the honor of buying an honest-to-goodness 82nd Airborne paratrooper veteran a beer in the square of St Mere Egliese. Right smack in front of the church with the replica of PVT John Steele suspended from the steeple from a parachute. If you've every seen "The Longest Day", you know the one I'm talking about. I hope to re-live this feat again this year. And I'll be buying myself a few of those beers as well. My wife also took a picture of me looking out of the observation port of the same bunker the German officer who first spots the invasion fleet was looking out from in the movie. Might try that again, but a little more in the exact spot this time.
I'm bringing along a uniform in case I have the opportunity to 'strap hang' with the 173rd ABN BDE and get to jump into Normandy. Granted, its been 15 years since my last jump and my wife will probably kill me, but who could pass up an opportunity like this, if it presents itself? Who knows?
Anywho, see you all in 8 days or so.
Bob

I don't have selection in Power Point. Could you send me an example?


I'll have to get my portable hard drive and post an example.

Bob and progress, it has been more than 8 days...

Realizing this is an old thread, I'll just pile on to say that having just gone over a similar Predicta, I found exactly the same modification. The wire to the Vert Lin pot had been cut and an oversized 300 ohm 25 watt sand resistor hacked in it's place. Vertical linearity and height were horrible, but a few minutes with the sub box produced a much improved image with about 900 ohms. I assume this pot is prone to failure, and the 300 ohm value was deemed correct at some point.

Bob

I had to try this method of removing rust from a tuner shield from a kenwood kw-1100u amp..interesting as within 3.5 hrs it has dissolved part of the SS spoon off completely..LOL, i find it entertaining.. and interesting..and the rust spots are almost gone.. :)

OP seems to have dropped off the planet.

I had to try this method of removing rust from a tuner shield from a kenwood kw-1100u amp..interesting as within 3.5 hrs it has dissolved part of the SS spoon off completely..LOL, i find it entertaining.. and interesting..and the rust spots are almost gone.. :)

That's a real nice power supply you've got there!

OP seems to have dropped off the planet.

Maybe he never made it back from Normandy ?

The Power supply shot is to Show The voltage and current of the "part" in the bowl was drawing and it's setting..(which was 6 volts).. interesting as soon as you lower the rusty metal part into the salt and water mixture it really draws some power during this process..:)... this why I am glad I don't have a Wife to get upset at me for using silverware from the kitchen drawer for this ...

hello....

hi........