fixing for a friend, only had minor issue, needed a new vert lin pot, the sectional cap for the vert out k bypass was open, so I restuffed it (also had some screen caps in there), left the others alone (doubler and filter b+ filter).

would not lock vert sync, had a very high sync tube plate load resistor. Other than that it was fine. The IF audio tube was weak, and has an intermittant socket (guess that is it the tube has a sweet spot that make it work). I checked the HOT K current its in spec at 100 ma as long as the screen is set to the min to just fill out the width. The HOT had -35v on the grid, should have been -45v, tried swapping out the tubes little change.

checked the grid resistance it was high, SHB 700k was 1.2 meg. there are 3 resistors that make up the total. I decided to leave it alone since the only way to fix is to crush the resistors, and pig tail from the top. Its pretty tight where they are so 1st do no harm.

anyway I am giving it back to him for a long term burn in, if goes well he will get the cabinet repainted and some new grill cloth installed (he has the right stuff). Should be nice when all done, I just figured it should be watched for a month or two before getting the nice paint job on it. That way I will not have to worry about it if something goes wrong in the short term. Of course with all those old resistor still in it I suppose it will need service at some time in the forseeable future.

Just for fun I hooked up my VCR out to a pair of rabbit ears, and used the predicta antenna to pick up the signal, all of about 4 ft away. Broadcasting "Planet of Vampires" from the mid 60's.

What a total deja vu exp, I am watching a poor B&W pic, just the way I would hav seen an old sci fi off a UHF indepedant station back in the 60's snow and all, its GREAT!!!

2nd one now, this one is mine, I have had it for over a year but never touched it due to the horror stories of working on a Predicta (this is the 17" princess model, red with metal frong grill).

Started by removing the main chassis (left the tuner in place for now). Very easy well thought out engeerning to get it out.

It not that bad at all, infact the compact sturdy chassis make it easy to flop over on the bench to get at the pcb (well the parts that are exposed anyway).

cleaned it with a soft brush and compressed air. Then moved on to alchol and q tips on the pcb to get the schmutz off the top of the pcb (I like to see what I am working on).

Popped off the IF strip cover, same deal Air, brush, q tip.

Stuffed the smaller can cap, it was complety open, was a bypass cap (low volt hi cap) for the vert amp, and a couple screen bypass caps in there.

I like the fact that there are no resistors tied to the can lugs just wires (this is the case on all 3 cans). Much easier to remove wire with out other stuff in the way.

Check the single doubler, fine, checed one section of the remaining 3 section cap, it check fine, I have found that if one section is good the remaining ofter are as well. I will get around to checking later.

Next up I start replacing all the black beauties, the 1st 4 all tested bad, I stopped checking after that.

There were a few that were standing up, I was able to use radials on those for a neater apperance.

I was able to replace about 70% of the caps from under the board, solder wick is your friend her since the solder sucker cant always get in tight places.

I am assuming the pcb is not though plated on the holes so you hav to bend the leads down flush to the board when soldering (I did not notice this on the 1st one, but figued it out quickly, I had not worked on such a old pcb before).

On the ones that just had no access at all I clipped, cleaned, and pig tailed the replacement cap, careful to use hemostats as heat sinks and to make sure the wire remnant did not fall though.

there were a few resistors that were out of spec. same deal as with the caps was able to do some from below.

The biggest problem was a big 390 ohm resistor next to the HOT. It was reading 470 but had a 10% band on it so I went ahead and replace it with a sand resistor, it was tight and I had to work from above, but got it in.

there were a couple I did not have so will have to make a surplus store run today (or pick up at the hamfest tomorrow).

I check all the tube resistance reading, all good to go.

checked all the coils (tranny,fly,vert,audio) again good to go.

the 17" crt was very very weak (no emmisons at all)

put the CR70 sencore to work (rejuv and auto restore) worked like a charm, strong emmisons and good cut off, and surprize good life test!

lubed the trim pots (little rusty and stuck) they seem fine now, beside I have some spare JIC.

cleaned and lubed the other pots (they were kinda funky on the resistance checks, seem ok now)

I am going to sharpen up my pick and tighten up some of the tube sockets that seem a bit loose, then will clean sockets, check tubes, clean pins.

I am thinking of making up a replacement for the fusistor (its there and good).

the replacement will be a couple thermistors in series and a fast blow fuse. That should soft the start to the caps and tube on the B+ and provide a sensitive fuse (with the soft start I will be conservative with the fuse rating).

Will also put a thermistor on the primary side to take some load off the switch.

Lastly will finsh up with a replacement saftey cap (the orig was a BB and was gone but the remaings where in there).

one thing is for sure, yes the chassis make it hard to work on, but the upside is its very stiff (box section chassis) which would translate to no flex at all on the pcb. From what I have seen this model anyway is pretty well designed and amazing how much TV was squeezed into a small space.

I really like how easy it was to get out of the cabinet the plug in tuner power supply was a nice touch.

How was the area around the audio output tube? The pcb on mine was an issue there due to the heat of the 6BQ5. I was kinda surprised they used that tube with a relatively small speaker. Had to get creative making some connections there. That area of the board was a bit tricky being right next to the chassis. the only way to do it right is to remove the board... and I simply did not want to go that route.

not bad at all Charle, the tube socket is a bit loose but the pick should fix that. Maybe I have a low time one. I also thought the 6bq5 was overkill a
6AQ5 would have been plenty.

while checking over my work I noticed a couple caps that I "could" do from the bottom, so will re do those, and in what must have been a late nite frenzy I put a 500v cap in a 600v spot, I have the right one so will redo that.

I don't really mind as doing this is fun anyway. Something about getting it as "right" as possilbe is intriging as opposed to getting it close enough to work. I find that the solder wick and pencil iron can get into some pretty tight places. Looks like maybe only one of the caps will end up being totally inaccessable from the bottom.

I realy hope those k networks are going to be ok.

My buddy is really getting a kick out of his, I am glad I was able to help him out, its nice to see others get excited about old TV's.

I built one of those combination components from scratch... turned out pretty good being my first time. Cant say it was pretty... next time i will use a small pcb... but still worked great.

yep thats the plan if need be. I have pleny of copper clad perf board, cut grooves in it for paths and solde as need be. did the one you replace have any obvious visual defect's (broken cracked etc...).

No visual defects. I was advised by an uncle that i might as well do it while I had the set apart.

this one is in pretty good shape overall, it looks like it had a tube socked replaced (the sync tube socked) at some time, but other than that looks completly orignal. I amost hated to recap it, but its better that it works than be orig and set on the shelf never getting turned on.

pic of the now cleaned up pcb. lots of cleaner and Q tips.

Cap count about 13 so far, that .15 100v is next as is the .22 standing up.

there is a missing cap next to the vert out tube (c14 on the pcb but that is not what its called out as on sams) I could not locate on at the surplus store, its a .0015 1kv, in the plate circuit of the vert osc. I am going to a hamfest tomorrow, so hope to stock up on some caps there. If Not mouser will be next.

I have a .0022 orange drop 1600v and a .001 1kv but since its in the vert feed back circuit I would like to get close, I assume its somewhat critical for the correct frequency of the osc (although there is prob enough adj in the vert hold to get it close to the sync pulse).

I did go back and redo some of those over the top connections to below the board. I ended up with just 2 caps that I could not get. I replaced a few resistors, also under the board but for the big sand resistor (you can just see the white by the 6dq6 base).

I started off with a pcb that you could not see any of the print on the top, every spot you touched the q tip to came back filthy. After a couple hours work you have to try to find a spot that is not clean. Its nice being able to read the descriptions on the board.

did the socked tightening and cleaned the pins sockets with contact cleaaner.

I am hoping the networks are ok, if not I will be building replacements that are form and fit compatible using small copper clad perfboards and discreet parts.

Still need to do some tube testing mainly looking for shorts.

The fly looks pretty simple, I have a few small flys that I may play with to see if I can find one that at least matches the coil resistance. I wonder if anyone has tried to find a non listed sub?

single ended 6bq5? Fun, fun. Bet it has a great sound to it .

yep kind of a waste considering the speaker and enclouser.

Not being able to leave well enoung alone, I revisited one of he top mounted caps. I was able to bend my soldering gun (not my tool of choice for pcb work mind you) tip and get to the hard spot. little bit of solder wick to get all the solder out and some careful extraction yielded positive results. I now am down to two caps that vert osc plate and a single .22 upright cat bypass.

the vert osc should be no problem getting access to the bottom not easy but no harder than that last one. the upright one I may have to yell uncle on it.

Of course I could leave it for now. It tested fine with no leakage at all, even at 150v vs the 100v rating. Its a cathode bypass so I dont think it sees much in the way of voltage anyway. Of course if it did short it could possibly damage my vert out tranny so maybe a good idea to replace anyway.

Getting close to intial power up...

...

I will check them out, thanks Andy.

I may just plug in the CRT and use a .002 for the time being on the vert plate cap. I can at least see if I get a raster, and know the fly is ok.

runing out of time though since the hamfest is today so may not get to it tonight.

The cabinet is red and looks pretty good, but the inside is covered in surface rust, the outside has one or two spots of rust (not bad just enough to mess up the paint), overall the paint looks very nice.

So If I get it running I will have to decide if I want to keep the orig paint or get it stripped, get rid of the surface rust on the inside, and then repained.

The bright work is the same not bad not pefect. I will get some pics later.

Not that I am trying to make this thing an investment, but I dont want to do something dumb like refinish it if that is big mistake. any comments on this please. For me if I get it working I would like it to be finished so it would look the way it did when new.

we got HV, we got raster, we got intermittant damper tube socket and intermentant vert osc tube socket.

At least I know the fly is working, 17kv on the anode :banana:

I just laid the crt on the side and hooked it up.

I am hoping its just loose pin contacts, when I tested the resistance I did it with the tube out so its possible they are just not quite touching the pins with the tube in.

Breaking out the pick for some more work. I hope the damper tube socket is not covered, I know the HOT is but not sure if the damper was.

checked the tube socket solder reflowed but it looked ok before, same deal, I think the problem maybe some other part that is being affected by the movement of the tube (it takes quite a bit of force to get it to work) causing the pcb to flex. I will turn the brightness all the way down and get a wood chop stick to it and see if I can prob some other parts on the board to find the problem. Damper seems ok now that I have tightned up the filament pin sockets.

Dave, I remember having the same problem with my damper tube socket. In fact, i don't think I ever fixed it.... just wedged an empty tube box between the damper and the HV cage. I remember getting fed up with it and finally said screw it! It's been a while since last time I turned mine on... but I remember that was the deal... make sure the empty tube box was wedged in there just right to make it play. Once that's done, it plays really nice. :D

found it, the vert tube socket had a micro fracture at the pin socket, I tested ok for resistance since I would touch the prob to the pin socket, which in turn pushed it down and closed the fracture. With the tube installed the push was gone and the fracture would open up.

I found it by using my tube test socket, and cliipping on to the test point rather than pushing it with the prob, bingo it opens right up.

I think I have a pcb mount 9 pin mini AND this is an easy to get at one, so I plan to just remove the socket. I tried to bridge over the fractrue, I may try that again I just have to get a small file in there to clean the metal so the solder will stick. the damper seems ok for now.

I am not sure if its a socket or pcb issue with the damper, I will play with it some more, but like Charlie says I may just move it to the sweet spot and be done with it.

I need to check the HOT current next to see how that is doing.

I have a buddy that does vacuum forming I may get him to mold up a new cover for the CRT, mine is ok but I would like a crystal clear one it I get this working right.

well there were two fractured pins, looks like a design flaw in the socket there is a stress riser right at joint from the pin socket to the down leg that is soldered to the board. I am sure I will replace this now rather than just tacking on a quick fix since even if I did get it working there is a good chance of another fracture. Charlie the damper is acting up again....

I think I have a technique the fix the fractured pin joints. Good thing to since after fixing two on the vert osc, another on its filament opened up. I will keep at it regardless, I would like to see how durable my fix is, before resorting to socket replacement. Dog gone damper is still fighting me. I tried tightening up the pins again, I will see if I can inspect the bottom.

Good thing I checked the HOT K current, 200ma, range should be 100-140.

I adj the screen voltage to get the current down to 110ma, of course I lost some HV and screen brightness but better that than the fly.

My guess is the higher line voltage translates into more voltage at the B+ (duh I did not check that yet) in which case the screen dropping resistor in series with the screen pot (width) is simply too low a value, that is I would think that if the pot was set to zero thee dropping resistor would set the max at no more than say 160v. Of course perhaps the idea is this is supposed to be set at the factory and hopefully the owner would not mess with it (but it is exposed at the back).

Well 1st things 1st, I will go back and check that B+ if its high I may up the resistance of the fusistor to try and compensate for the higher line voltage, then go back and check that screen/K current.

On the damper... is the bad connection in the socket or the pcb trace itself? Perhaps you follow the trace to the previous point, solder a wire there, then run the other end to the bottom of the socket of the damper.

Thats what I did Charlie, it was the trace for the ground pin (looks like someone had already done it for the 6v trace). I was able to get some wire in there and follow the trace with a bent up solder gun tip.

I think I got it licked, going to see if I can get it to go out now by wiggling.

progress...

1st screen shot off tuner input.

still a long way to go, Pretty sure it needs some new tuner/IF tubes, maybe a video amp tube.

Awesome! :thmbsp:

Looks like that CRT has some good life to it! :yes:

Cleaned the tuner, much better contrast now, better sync lock, volume is still a bit lower than expected, but I have not tried a new preamp tube.

has this odd whitesh line in the vert, I can tune it out, but at the expense of not as sharp a pic. IIRC an earlier poster said this may be a part of the color signal.

I have not yet hooked up the IF sweep gen to take a look at the band pass. I will prob do that just to see what it looks like.

that darn damper is acting up again, Geez I see what you mean Charlie, it's a real PITA...

think I finally really really got the damper figured out, I could not understand why it was still not grounding even with the wire along the track, then I realized the stake that pops up though the pcb and is then bent over and soldered to the stake that is part fo the chassis was moving, the joint was not solid. I cleaned it up fluxed and got out big beartha to resolder that stake. Now I cant wiggle the damper off no matter what, whew, that was getting to be a pita.

there is a lot of little tricks on these predicta's...

Are you using the coxial connection straight from an old VCR/DVD combo? Or does your source go thru a seperate 20 dollar RF modulator?

whoo hoo...

dinked around with it a bit more (touched up the audio IF) the damper is fixed :banana:

no way I could get it to go out. the only slightly sensive tube now is the vert osc. I "may" go back to it but really its pretty solid, you have to move it around on purpose to make it go out. I will go thru my tube socket stash and see what I have. It is an easy one to replace (completly exposed) so I guess it makes since that I should do it while I have it out.

a few other things I did to help the overall pic

cleaned the tuner RF conncection (both the female on the tuner and the male from the IF strip) and polished up the surfaces with very fine sand paper. There was a good bit of oxidation. Same with the CRT cathode connecting pin, both the pin on the board and the female connector from the CRT head. Again lots of corrosion there. The biggest gain was cleaning the tuner, it was not so much noisey as just low signal strength. I did not bother to check the resistors in the tuner, not sure if I should bother with that.

I am going to let it burn in for a while on the bench, if all goes well I will reinstall into the cabinet for a longer term burn in, then decide about stuff like repainting.

does anyone know if the finish on decorative bars that go up the sides of the CRT head are painted or plated? Mine are pretty messed up with surface rust. I was thinking of stripping them and redoing but not sure if its paint or plate.

same question on the base, it looks like steel that was maybe plated.

replaced the vert out socket, should have done that in the 1st place, very easy. I 1st solder wicked 90% of the solder from around the pins, then busted up the plastic from the top so the pins were no longer locked together. then using a solder iron I just put light pressure from the bottom one each pin one at a time, they just popped out, clear of the board.

The replacement socket was an exact match pin and size, but better built.

I used a round tool to ream the holes clean (just enough pressure to clean the remnants out of the way) and the new socket pops into place, the pins expand once its thru so it holds itself in. Use the solder iron again an its done. Nice a tight. I retest all the resistance measurements (this time with the tube in place and using very light pressure so as simulate actual use), all test good. I tap the chassis on the bench some to shake it up and knock any loose debris off, then go over it once more looking for bit of solder or any other stuff (trying avoid any FOD) plus that should be a good stress test.

hook up the crt/tuner, plug in and voila works and all the damper and vert can be messed with with no problems at all. I need to check over on last tube a little 7 pin job, that is also easy to get at. If it is even slightly intermitant I will not hesitate to replace it as well.

I hope to work on cleaning up the metal chassis this weekend, will prob use some navel jelly to get the surface rust out (the inside is rusty the outside is pretty good, not perfect), then have to figure out if I should try to paint the inside or just leave it bare. I figure it should not rust given it will be inside.

Still pondering taking it to a paint buddy to strip and repaint the red cabinet, and what to do about the rusty brass plated uprights.

Most likely will just reassemble and enjoy as is (well after getting the dirt dobber nest out).

...Still pondering taking it to a paint buddy to strip and repaint the red cabinet, and what to do about the rusty brass plated uprights.

Most likely will just reassemble and enjoy as is (well after getting the dirt dobber nest out).

I used rust remover on mine, then just sanded down the existing paint rather than strip it. A couple coats of primer, wet sanding then a couple finish coats.

I have rusty metal arms too. I got as far as sanding down the pitted brass plating, but that's it. I might just use some metallic paint. It should prevent rust and can always be stripped and replated down the road.

Here's some pictures if you're interested. http://www.flickr.com/photos/70039806@N00/sets/72157614533585480/detail/

That's inspirational, was that a particular brand/color paint?

I don't have a dud, I wonder if hawkeye has one so I dont have to spend extra just to find and send one. My crt is fine, but I also would like a spare.

How the heck to you reattache the anode to the crt? right now I just have an extenstion wire up to it for testing, I could not see how to get it back on without removing the shell (and is that difficult?).

That's inspirational, was that a particular brand/color paint?

I don't have a dud, I wonder if hawkeye has one so I dont have to spend extra just to find and send one. My crt is fine, but I also would like a spare.

How the heck to you reattache the anode to the crt? right now I just have an extenstion wire up to it for testing, I could not see how to get it back on without removing the shell (and is that difficult?).

Thanks, but it doesn't work - not even close :tears: I gave up on it about a year ago. Since then I've picked up a spare chassis and CRT. I'll get back to it someday.

I used Rustoleum protective gloss enamel #7762 'sunrise red'. I don't think it's quite right though - maybe a touch darker like #7765 'regal red' :scratch2:

I did remove the shell. The only thing I had trouble with is removing the two little screws that hold the brass cover plate on. I've heard folks often have trouble with the spring that's underneath too.

That's a NOS 17DAP4 I picked up (my original CRT is fine too). I'm pretty sure it's a very good substitute for the original 17DRP4. You can get either one here (http://vdc.mybisi.com/products/all-categories_0/?page364&s=).

hmmm mine has a 17DAP4 installed with a philco sticker and all. I wonder why the schematic calls out a 17DRP4?

hmmm mine has a 17DAP4 installed with a philco sticker and all. I wonder why the schematic calls out a 17DRP4?

Dunno - mine has the Philco sticker too, but it's a 17DRP4 (10L43 chassis). I think the specs on the two CRTs are virtually identical.

Speaker was shot to heck, found a donor from an old zenith. got the speaker back installed in the front grill, will bolt it all back together this weekend.

got it all back together, looks great, a little sync buzz that is some what tuneable. I prob should have checked the alignment curve while it was out but I just wanted to get it back togehter. I picked up some new feet for it, the orig were long gone. I could not get the anode back on, no way, so I decided to pop the shell off. Wow, what a pita... no problem getting it off but putting the retaining spring back on almost got the best of me.

At least while it was off I cleaned the CRT face and the back side of the plastic mask. Lotsa brown gunk came off the CRT screen.

Anybody have exp with polishing up plastic? this has some fine scratches that make it less than perfectly clear.

Overall it has a very decent pic, good lineairity, interlace, and focus. The CRT is a little brighter on the bottom 1/3 so dark scenes are more grey toward the bottom. Also if bold bright print is on the screen the horz before and after the print is darker.

Also if bold bright print is on the screen the horz before and after the print is darker.

AGC maybe? :dunno:

I dont know Charlie. Maybe I should clamp it and see if that makes any difference.

I used Novus plastic polish to spruce up my CRT cover on my predicta. I was amazed at the job it did. I have enjoyed this thread, nice job.

Thanks Dan I will look for it. Is that a on line purchase?


here is a pic it looks a lot better than this, those interference lines are not real, must be the camera.

Lookin' good. Turning off the flash on your camera will give better screen shots (might need to put the camera on a tripod).

I'll second the vote for using Novus plastic polish #2 on the cover. Available from http://www.tubesandmore.com/ and probably lots of other sources. Don't bother with #3 (too abrasive) and #1 (too feeble, almost like water). #2 will bring just about any plastic to a great shine all on its own.

Phil Nelson

sounds good, I will order the big bottle Monday.

Is there a way to hook up the anode with out removing the shell, just for future work?

couple more pics. I put on new feet with some felt pads on the bottoms to protect what it sits on. Got the feet (several styles) at skycraft surplus.

used the novus polish, very nice.

Still on the fence about how to get the arms re brassed, not any luck with local plating companies.

I touched up the vert height and lin, looking good.

I prob should go back in and restuf that multican cap just for relialbilty sake.

Also still want to replace the fusistor with a fuse/resistor/thermistor combo.

I will prob do that when I restuff the cap.

used the novus polish, very nice.

Still on the fence about how to get the arms re brassed, not any luck with local plating companies.

I touched up the vert height and lin, looking good.

I prob should go back in and restuf that multican cap just for relialbilty sake.

Also still want to replace the fusistor with a fuse/resistor/thermistor combo.

I will prob do that when I restuff the cap.

I'm in the same situation with my set's arms. I haven't had much luck finding any place to do it either :(
I saw a set on ebay where they had all the brass bits replated and it looked fantastic.