I got this from a teacher for a graduation gift.

well, i need to restore it.

I powered this beuty up on the variac, and not to my surprise, the tubes lit with no audio or picture. needs new caps, and both seleniums.

Charlie, do you have the sams?

also, this thing has the so called "ballast tube" that needs replacing. a couple of those filiment resistors are burned open, and there are others that are intact. (shorted 'lytics i think).

also, anyone that has restored these in the past, is there any advice i need to watch out for?

i restored 2 other TVs, and one radio, but i always ran into a tricky problem.

also, how am I going to rebuild the ballast tube with modernized resistors.

Any ideas? sams would be usefull here.

lol.

Originally posted by mbates14

Charlie, do you have the sams?


I'm not at home right now. Currently on board ship docked in Philadelphia and won't be home till mid-late June. If you haven't found one by then, I'll look and see if I have it.

ill just order one

the ballast tube is bad, how do I rebuild?

Phil Nelson has a great article on his site about rebuilding the ballast.

http://antiqueradio.org/motvt73.htm

oops, its a ts-4d in a ts-4j cabnet.

go figure.

I contacted justradios, they are making me a capacitor kit, and going to send the sams.

I have one problem:

this chassis uses (5) .005 6000v capacitors.

they dont carry those, and I cannot find them at allied electronics.


any ideas?

You can use the .0047 mfd 6000 volt capacitors that Allied carries to replace the .005 mfd 6000 volt capacitors.

Ross

I did an analysis on the chassis, and I believe its the powersupply that is not working.

like phil nelson said on his site, that he replaced the filters and selenium, and up pop the picture.

well, i powered mine on through a variac, the resistor "wires" on the ballast tube glow red for a second or two before the tubes start to warm up. There is alot of heat on the ballast tube. but, on the other mica, the resistors were cold.

So I think, that someone "just plugged it in" sometime in the past, and the shorted lytics blew out the seleniums. so there is NO volts on any tubes period. except for filiments.

There have been a lot of discussions of these sets on the antiqueradios.com TV forum, including many that I have posted.

http://antiqueradios.com/cgi-bin/forums/forumdisplay.cgi?action=topics&forum=Antique+Television+Discussions&number=6&DaysPrune=20&LastLogin=

I'm travelling at the moment and unable to give detailed answers to your questions, but do a search at the link above and if you have further questions, feel free to email me. I have restored 3 recently and pretty much know them inside out (which may not necessarily be a good thing :).

As for the power supply problems, I would start by assuming that all rectifiers, filter caps, and ballast sections are bad, and replace everything before applying power again.

These are neat little sets, humble as they are, and my friends love to watch them in action. Good luck restoring it and again, contact me privately if you have questions.

This is the model I have. It sorta worked when I got it; being stupid, I pulled a tube while it was powered up and watched a couple elements in the ballast burn up. Anyway, I managed to fit new wirewrounds in the ballast can, it was tight and if they were all burnt out my method wouldn't have worked, but it has lasted many hours so I guess I didn't do too bad.

Somebody should buy a large quantity of those 6K caps to resell-Allied isn't the easiest place to deal with, at least not on such a small order.

It took me awhile to find the right schematic as the ones I found were for a different version. Somebody online sent me the correct one.

there are several several several different chassis.

On the 6000V capacitors, the ASC metalized polyester caps seem to work great. For the .001 cap, the ASC part # is X675-.0010-10-6000 and the Allied # is 225-6015. On the .0047 cap, ASC # is X675-.0047-10-6000 and the Allied # is 225-6075. They are around 2.50 each.

also, this thing has the so called "ballast tube" that needs replacing. a couple of those filiment resistors are burned open, and there are others that are intact.

Do all the tubes' heaters light up, or just one of the strings? In any event, if a string's voltage adds up to about 85V, you could use a diode (like an 1N4004) with no filter cap to run that string off the 120V powerline. Remember that it's V^2/R = power, and that a diode would cut that power by half. So (1/2)(120V^2)/R =~ (85V^2)/R Tubes generally perfer that their heaters are on average at more positive voltage than their cathodes, so connect the diode's cathode to the top of the string.

If the string adds up to less than 85V, pad it up with a power resistor of appropiate size. using the heater string's rated current, and the amount of voltage you need to make it add up to 85V, R=V/I. And the power size needed: I^2*R =P This cuts waste heat down.

Ive gottten a schematic, and I tested all of the ballast resistors.

they are fine, except for one.

the 200ohm one is bad.

the others are fine, and ALL of the filiments light.

there is dead 0 volts. both seleniums are open, and the B+ supply resistor (200ohm) reads about 1 to 2 megohms.

one of the main filter caps checks for leakage.

All of the other caps test fine. no shorts.

the 200ohm one is bad.


the others are fine, and ALL of the filiments light.

there is dead 0 volts. both seleniums are open, and the B+ supply resistor (200ohm) reads about 1 to 2 megohms.




Better check for shorted electrolytic B+ filter caps. That might have blown up the 200 ohm resistance and the seleniums. I'd just install at some convenient and ventulated spot a new 220 ohm resistor and silicon diodes in place. The extra 20 ohms resistance is to drop the higher voltage the silicon diodes will deliver. But check for shorted caps first! Also all the wax caps will be bad and need to be replaced.

I know the caps need replacing, but I wouldnt necessarily say all the caps are bad.


I have an old 1950's silvertone, completely unrestored, and gives a beutifull picture. with the exception of one electrolytic.

I agree with mbates14. I have seen and own too many electronic devices with all or mostly original caps that work fine. There are probably a few variables besides age that determine caps life span and reliability. The popular idea of ripping all the caps out for new ones is ok if you have the money and time to rebuild television sets or if you wanted to put an old set to every day use. You can use a set with the old stuff but that way you will have to pull the chassis for repairs as they become necessary. There is something to be said for having a set that can be used for years without repair. Guess it all boils down to time and $$, or lack there of.....

the ballast resistor tube tests fine, except for the 200ohm resistor.

that sucker is reading in and along 1.8megohms. hmmmmmm..

need a new B+ supply resistor. all of the other resistors are all way well in tolerance. so thats why all the tubes are lighting.

anyway, the filtercaps have to be bad, because the seleniums were open, and that supply resistor is nearly open.

Guess what guys! my 7jp4 is toast! F**K

well, I recapped the whole set, replaced the seleniums, and the bad ballast resistor.

The set will turn on, filiments will glow. The sound is there, and the HV is there. I can see a slight blue glow, and the filiment lights on the rectifier tube. so my HV is there.

the filiment on the picture tube is on, and i can also see a slight blue glow on the neck of the tube. A spark jumped off of the tube to ground once, but i had to move the tube more away.

there is nothing on the CRT. no raster, nothing. My drive signals are ok on the tube acording the schematics. my volts are within tolerance. by like 1 or 2 volts.

The only thing i didnt do was change the 3 .005 6000vdc caps.

I did replace the .001 6000vdc caps. I had those. I cannot get the .005s No CC.

but, if those were bad, the HV wouldnt be there right? well my HV is there. my volts are on the tube. and the tube is glowing, and there is a slight blue ring around the clear glass on back of CRT.

but, nothing on phosphor. no raster, no pic.

Don't give up on the 7JP4 yet. Replace the .005s. That will probably get you a raster. You can buy those caps at Allied.

Steve

well, what are the purpose of the .005?

every online store I know takes credit card. I dont have a credit card.

I thought if the .005s were bad, there wouldnt be any HV. well, there is. becuase the filiment is glowing in the HV rect.

also to note, im sure it doenst matter, but I ordered the cap kit from justradios, and they didnt have any .005 6000vdc.

They had the .001 at 6000vdc, those are the blue ceramic. I put those in.

uh oh. it might not be the tube, but rather:


after inspecting the HV section, I noticed a (old looking, weird) brown plastic cap, that has 500mmf and rated 20KVDC.

What the?? and ideas?

thats just one.

There is also a large aluminum can cap right near the 25l6 H out.

YES!!, well kinda.

I replaced those 2 oddballs, with the correct ones that were in the schematic (those were actually the .001 6000vdc, with the wrong type installed from in the past).

now i got a raster, but its just a very intense dot in the center of the screen, so I killed hte power almost immediatly.

Those .005@6000V are in the sweep circut, and are known for going bad, even early in the life if these sets, they were usually the cause for their failure, and instead of getting the set fixed, most people wanted a bigger TV now available, so they were put into the attic, with almost no life on the other parts or CRT.
When those caps go leaky, there will be no deflection, horizonal or vertical, so you get the dot in the center of the screen. Since this is an electrostatic deflection set (no yolk), these caps are needed, though I'm sure somebody out there can explain why much better than I could. Sometimes, the caps will cause beam to be deflected off the screen, giving the impression that the CRT is bad.
I would also try to avoid the blue ceramic caps, espically in the deflection circuts, since they are known for causing jittering pictures that you can't get to stand still.

ok.


I missed a cap in the corner by the 25l6.

I replaced both .001 with blue ceramic.

the 3 other .005s i havent replaced.

The set now powers on with no vertical sweep. only horizontal.

the .005 caps are in the vertical section, so im guessing those are at fault.

Slowly, but surely, the set is awakening! :)

justradios (or somebody else convenient) really should stock those hv caps. They could just buy a bunch of them from Allied and resell them at a profit. Maybe its just me, but dealing with Allied was a pain in the neck.

Originally posted by bgadow
justradios (or somebody else convenient) really should stock those hv caps. They could just buy a bunch of them from Allied and resell them at a profit. Maybe its just me, but dealing with Allied was a pain in the neck.

Maybe even somebody on the group could buy a bunch of them, then when somebody needs a few they could go to them and get just a small amount, instead of having to go through Allied and their minimum order, which is a real pain if you are only planning to do one set.
You could sell them at a small profit, it would still would be cheaper if you just need a few, and you could save on shipping, probably less than 1.00 for first class, caps don't weigh very much.
Just a thought...:)

you got that right. its 25.00 no matter what.

Originally posted by maxm
Maybe even somebody on the group could buy a bunch of them,

Actually, I did that the last time I ordered, with the idea of selling some of the surplus.
If I actually got around to recapping all my electrostatic sets I wouldn't have any surplus :p:

However since that's probably not going to happen soon I would be willing to part with 3 of the .0047@6000 for $3 each (what they cost me basically after tax&shipping) and I'll pay the shipping.

I'll throw in a couple .001@10,000v Ceramics that work great for the Horiz circuits.

Eric

actually, 2 of the .005s at 20kv I had are hermetically seald, and I reinstalled those. I now a full raster. its a gray raster with retrace lines.

for some reason, there is no picture, and no audio. (dead audio).

just a full raster. thats it. entire set was recapped. Also, it looks like the vertical linerity is bad.

I have volts going to all my tubes.
my tubes test ok.

also to note, the focus isnt that great, and the contrast control has absolute no effect.

i wonder what the issue is.

I know there is a bad problem somewhere, because when I pull out the 6au6 video amp tube, the raster doesnt change at all, except fade, because the string of tubes are knocked out.


I have a scope, but I have no idea what to look for.

well crap, it had very week sound for a little bit, and I was hooking cable up, I got a station, and then something happened and the sound went back out again.


as always, nothing on the raster.

If anyone would aide me into an area of the circuit thats causing the trouble, let me know.

I tested the audio stage, by injecting a tone into the volume control. it came out loud and clear. Im leaning more and more to the IF stage.

Im not sure exactly how to test the video. I know audio works, by injecting a signal to it, right after the limiter.

anyway, I have a good calibrated oscilliscope, but I have no idea where to probe it, and no idea what waveforms to look for.

Help! Thanks!

BTW, I got the .001s and the .005s replaced. I have full raster. no pic.

UH OH. I ran into a mindboggler, which would cause this trouble.

I was looking at the sams, and it has all the volt measurements from ground point.

Everything looked good, until I ran into the 12AT7 Osc/mixer.

it has a problem. The mixer plate, grid, and cathode volts are fine.

BUT> here comes the problem

the tuner osc plate voltage is normal, the tuner osc grid volts is supposed to be at -3.2vdc, I get about 141vdc.

the cathode is supposed to be 0v (ground somehow). it reads about 130vdc.

Thats my problem I think.

Whats going on here? the resistors in this area test fine.

Im studying the schematic, but Im comming up with nothing.

here comes the funny thing, it doesnt happen till the tubes warm up.

I changed it, and it still does it.

its solid state PS so the voltage immidiately shows at power on.

I pulled the tube, and the volts dissapear off of the cathode pin.

i plug it back in, it begins to climb as the tube warms.

ALAS!! The set has awakened!

I found out that someone in the past has f**ked with it, and the RF Choke to the oscillator for the tuner, has been wired to B+

Well, I took it to ground like it was suppoesed to be, and up popped the picture!! I can now pull in local stations.

Its not fully awakened yet. The sound is still dead, and there is a problem with the vertical.

even though the caps have been replaced, the top half of the vertical is streteched, and the bottom half collapses to a line. You cant see the bottom of the pic. its a line. the top half works.

Any ideas? it looks like bad vertical linerity on steroids.

Originally posted by mbates14

Any ideas? it looks like bad vertical linerity on steroids.

Did you try adjusting the verticle height/linerity controls? I had a set once that I thought had a faulty part in the vert circuits, and after going thru everything, it turned out that the controls were simply turned all the way to one side. I felt pretty stupid after making that discovery, but I bet it happens often.

it doesnt have a vertical linerity control, at least I cant spot it.

Also, the sync/clipper circuits arnt functioning either.

I can lock the vertical and horizontal to one scene, but if the scene changes, or the brightness of teh picture changes in the scene or if the picture starts to move like in a commercial, it will loose lock. horiz lock is worse than the vert.

I think that clipper circuit failed, because I pulled out the clipper tube, before the string of tubes started to fade out (wired in series). no change in picture. The sync circuit has problems. and the sound is absent.

I know ive kinda been running on and on and on with this thread, and it is probably misleading.


I am sorta treating it like my blog. But, go ahead and ignore everything above this point:

The set is in now working order, the sync is locked, the sound is preasent, and the picture is on the CRT.

The problem I cannot seem to be able to figure out is the focus is sorta bad, and the linerity is very very bad.

The tuner happened to be on CSPAN lastnight, and dick cheney had a very bad case of the coneheads.

Also, I checked the (2) 4.7megohm resistors between the two .005s at the vertical output plates, they check fine, but I replaced them anyway. The two 1megohm resistors off of the focus pot test within tolerance.

The 2.2meg series resistors on the focus pot test fine also.

I dunno what the deal is.

I checked the (4) 10megohm resistors around the vertical output section, they all test perfect.

I dunno what to do now. Its weird. Unless one of my HV .005s are already bad. I dunno. I can center the picture. but the linerity is horrible, and the focus is somewhat bad.

Help. I may need a new batch of .005s

On those electrostatic sets I often replace a lot of the resistors over 1 meg especially in the sweep and HV circuits. Your vertical problems could be caused by one of the mmf caps being bad. Also, recheck the caps that you replaced, it is not hard to put in a .001 when it should be a .01 or something like that.

Steve

I have no idea how to test an MMF cap.

I have a Capacitor checker on my DMM. thats it.

Don't test capacitors, just cut or unsolder one end and solder tack a new one in if you do not want to replace it right away. I'll have to dig out a schematic of your set to let you know which ones might be causing your problem.
Steve

I have the schematics of my set as a jpg file.

Its a TS-4D

If you want me to post them, or email them to you, I will do so.

I sent you a PM.
Steve

you also have a PM

Pictures are worth a 1000 words! See for yourself what my problem was.

The sync issue was a bad 25mmf cap.

I noticed most of the MMF caps are wax/plastic caps.

and #2 :puke:

and last but not least, picture #3.

That is the actual picture you see. Actual focus.

The picture looks almost exactly the same on the face of the CRT, but its not to scale ;)


the two 4.7megohms on the plates of the vertical circuit have been replaced, but they didnt make a difference. all the high megohm resistors are well within tolerance. couple of them read exactly 10megohms.

Did you use Ceramic disc caps to replace the 6000v in the vertical circuit? That will cause this type of problem in these sets. They seem to work OK in the horiz position tho.

Check the vertical pots for continuity from end to end also, not sure how they are used in this set but I had a Hallicrafters with that problem and it was an open pot.

Steve K told me that the reason I dont have a vertical linerity control, because each plate has the exact same waveform, but its inverse from each other, and for some reason its not the same on mine.

No, I dont have ceramic caps on the vertical stage. just the horizontal stage.

I have big brown caps on the vertical stage. There old, they were already in the set, and they test fine with no leakage. So, I used them. I dont have the money to purchase anything from allied, and they can shove that minimum fee up thier a**.

First, I thought one of those are bad, but I removed each one from circuit, and left the other in. Vice Versa, they both affected the picture when either one was removed. If i remove them both, there isnt any sweep.

So the caps are good, and I did a capacitor check on them through my DMM, and they test alright. There isnt any leakage.

I'm still suspicious of those caps, they could be breaking down under high voltage.

PM me with your address and I'll send you a couple new ones.

Eric


Originally posted by mbates14


So the caps are good, and I did a capacitor check on them through my DMM, and they test alright. There isnt any leakage.

Look at the waveforms on the two grids of the 6SL7. Do they look the same, but inverted (same amplitude, slope)?

The second half of the 6SL7 gets its signal from the plate of the first half, through C57, C142, R117, R58, C58 and R57. If any of these parts is bad it will result in an improper waveform on the grid of the second section, and therefore bad linearity.

you do have a point there.

ill get right on it.


Eric also mentioned that the HV caps could be breaking down under load. He probably is right.

These are NOS caps.

OK. I took pictures of the Oscilloscope.

The first picture here is the probe clipped to grid on pin 1:

This is the Oscilloscope picture of the probe clipped to grid pin 4.

I dont know if its my eyes, but the P-P isnt too great as the first one.

The first one looks mighty strong and healthy. The second one, its hard to tell.

Dont ask about my oscilloscope, and why it looks that way.

I took the faceplate and scale off, because the CRT is weak, and you can hardly see the trace through it.

If you didn't change the scope sensitivity between pictures, then it looks like the amplitude of the second trace is about 1/2 of the first. Check or replace the components I mentioned in my last post. You should have the same amplitude on each grid.

I didnt do anything to the scope.

I adjusted it according to the first wave, and just removed the wire, and put it on the second one. Didnt touch any controls.

well, the 100k resistor reads about 114k.

the 220k resistors reads about 264k.

the 100mmf cap is a huge one, and I dunno where to get one like that. its dark in the middle from heat.

How about the .004? Have you changed it? Any 100 mmf 600 v cap should work for C57. The resistors are close enough.

the .004 has been changed, and I changed the 220k to be sure, it didnt hardly make a difference, so the only thing left is the heat scorched looking 100mmf. Its a long cap that looks like a resistor.

the cap tests at 170pf on the DMM

MMF means PF I think

where am I going to find a 100pf at 600vdc?

wait........


you know what, After close inspection to the schematic and the actual point to point wiring, the .1mf between the .05, and the pin 6, or the cathod of the second side. IS MISSING.

its not in the chassis.

I wonder if its supposed to be there, or its just plain missing. That might cause this.

other words. C-56 isnt in the chassis.

DOH!

I found it. its between the plate of the OSC tube, and the ground.

sheesh.

It should be there. Try putting it in. That could solve your problem.

I said I found it. I found it over at the osc stage.


so, the only thing left is the 100mmf cap.

its an oblong cap that is crusty and almost black in the middle from age and use. its the long cap that sits right under the VO tube socket.

it reads as follows: .170 nf

on the dmm. is it bad? Thats the only thing left. the paperwax caps have been replaced the resistors have been checked and replaced.

oops forgot picture:

BTW. Disreguard the paper caps. Theyve all been replaced. along with the black ones you see.

I suspect that the 100 pf is OK, so before you mess with it, try this:

Take out the 1B3 so you have no high voltage. Then you can look at the waveforms directly on the the deflection plates of the CRT. See if they are about the same amplitude. If they are, I'm stumped. Maybe the CRT has something wrong with it.

If they are not the same aplitude, remove the two .005 coupling capacitors from the plates of the 6SL7 and swap them. See if the distortion changes. It is possible that you have a bad capacitor from Allied.

As I understood it the 6000v caps are NOS but still quite old, Is that correct?

Mike, I will send you a couple of fresh .005@6000v caps to try.

Meanwhile you could do as Steve suggests and switch those caps around and see what happens.

A word of to the wise Mike, if you have to choose between my advice and Steve McVoys go with his :p:

I am just a humble parts changer for the most part while he is the wizard.

Eric

...

He's already changed those caps, scroll back up to the post with the photo and read it again.

Hurry up and fix this thing already, this is like watching a soap opera! LOL

Anthony

LOL. it is. Its driving me nutso.

ALL OF THE PAPER CAPS have been replaced. ALL OF THEM.


Yes, there NOS. There not from allied, I DO NOT want to buy from allied, they can shove thier 25 dolla minimum up thier a**

That 100pf has to be good, becuase it has no deflection at all, when I pull it out of circuit.

If the vertical stage would just work already, I would close this project with a job well done, and it be over.

But thats not how the wheel turns.

uhhh.

I cant check the waveform if there is no HV

there is none. Heres why:

The vert output gets its B+ from the HV supply.

Any ideas?

id say the .005 are breaking down under HV.

I did switch them, the picture didnt change.

There is also a big huge aluminum can that is rated .005 at 6000vdc I havent changed yet, because I dont have a replacement for it yet.

according to the schematic, it looks like a bypass cap, it has to work or there wouldnt be any HV.

I replaced some out of tolerance 4.7meg resistors on the deflection plates.


one of the 4.7meg resistors was around 8.6meg in the vertical stage. I replaced that.

another 4.7megohm in the horizontal stage was about 30megohms. Does that look out of tolerance? LOL

that solved the focus problem, and the picture is better centered. but no result on the linerity.

after replacing some bad resistors

I have a question, What actually inverts the waveform? I know that the waveform on the first plate is acutally not inverted. It gets inverted by the time it hits the second grid.

What inverts it? whatever part is responsible for inverting it may be a little bit weak.

Imma going to head over to ratshak to pick up packs of 5, anything greater than 1megohm. that way if I run into somethi8ng, I will have the resistors on hand.


I might just go ahead and replace those 10 megohm resistors anyway.

After that, there wont be any resistors left to replace in the vertical section, other than caps.

When you supply an ac waveform to a grid of a triode, as the voltage goes more positive the output on the plate goes more negative. So as the output of one section of the vertical output triode is fed back into the grid of the second section, its output on the plate is the inverse.

no no no.

Its inverted before it gets or at the grid.

The 100pf cap and a resistor network connectes the plate of the first triode to the grid of the second.

The grid of the second already has an inverse signal.

If you look VERY VERY closely, between the first and second inverted wave, the wave of course, isnt very strong as the first one, BUT you notice the ramp on the sawtooth wave for the first one is streight. Its slightly curved on the inverted one.

Any ideas?

scope set on dual trace, both channels set exact same.

I'm sure the photos of the two traces are from the two grids. The first section of the tube has the grid connected to the oscillator. The waveform is amplified and inverted in the first section. A portion of the signal from the first plate (inverted as compared to the grid of that section) is fed to the grid of the second section. That is the purpose of the C57, C142, R117, etc. Those components attenuate the signal from the plate of the first section by an amount equal to the gain of the first section, so thr proper amplitude is fed to the grid of the second section.

The second section of the tube amplifies and inverts that waveform. So, the waveforms supplied to the CRT defectin plates are inverted.

The inversion process take place as Steve K describes it.

Thanks Steve!

I wonder whats causing the bottom inverted wave to be distorted like that.

Take a look at the slope, and the peaks.

Are you sure about this? could it be an electrolytic?
I haven't seen any 6000v caps in metal cans.

BTW, your new caps are on their way as of today.

Originally posted by mbates14


There is also a big huge aluminum can that is rated .005 at 6000vdc I havent changed yet, because I dont have a replacement for it yet.

according to the schematic, it looks like a bypass cap, it has to work or there wouldnt be any HV.

you havent?

well. Look at this:

BTW Thanks Eric!

Are you talking about this one?

It still looks like silver colored paper to me but...
I think that is the HV filter cap, doubt it would affect the vertical.

ok.

its metal. definatly metal. Its probably good then. It works.

couldnt one of those vertical .005 caps cause the circuit to produce a distorted waveform? Im not sure, but you never know.

oops. I did some math calculations. I think I know the problem.

You did say you sent those off right? ok.

well. The NOS caps I have are 500mmf at 20kvdc. someone said that they would work in the .005 6000vdc circuits. I said ok. I got them.

well, if im not mistaken .005 is 5,000pf or MMF right?

well these are 500mmf. so its .0005uf hmmmmmmmmmmmm.

that may be the problems.

That's the problem. That would explain the poor linearity.

i will dig up some new ones i know will work.
i got a bunch off ebay and they work fine in all the electrostats i put em in.

hey!! Eric, those caps came in the mail today.

Im giving you a BIG HUGE thank you!


That was the problem. The set is now fixed to operational order, and I now can conclude this project as closed, and a complete success

Cool, glad I could help :D

Originally posted by mbates14
hey!! Eric, those caps came in the mail today.

Im giving you a BIG HUGE thank you!


That was the problem. The set is now fixed to operational order, and I now can conclude this project as closed, and a complete success

YAY! Am glad you got it working....now how about a pic with it operating?

Anthony

I second that one. After all the head scratching and frustration you had with the Motorola...it would be cool to see the finished result of all your hard work.
-Tony

With as much as you have changed in that set, it oughta have a damn good picture! Lookin forward to seeing it! :)

yea, it works, except for it has a black bar on the left side now. I dunno why, but overall, the picture works.

when I get new batterys for my digicam, ill take a picture.

well crap, Just when I thought it was fixed, it conked out again.

both 12sn7 tubes died out, and the 6sl7 got super super super bright.


crap. I pulled one 12sn7. it didnt make a difference, altho it used to. So immidiatly, i thought of a short on the filiment strings.

i put the 12sn7 back in, and pulled out the other 12sn7. The string finally went out.

i switched the 2 12sn7s around.

this time, the filiment string didnt light at all, until i stuck that one culprit tube in. the 6sl7 started to glow really fast again.

i pulled it out, and just stuck the filiment windings in, and the entire string finally lit, and the hv and picture came back up, except there was no vertical.

but as soon as i stuck the tube back in, all the way the string would start to glow on that one side super bright again.

so, i have concluded that one of my 12sn7 tubes (the 1st clipper/vert osc) tubes have developed an h-k short.

im assuming, one of the filiment windings opened up, and then shorted over to cathode.

I put it in my tube tester, and it wouldnt light. the short bulb lit. so the tube is gone.

I dont have another 12sn7 to stick in there and try, I only have 2 6sn7s.

the question is, Why did this tube die like that? I have no idea. maybe it was age. I dunno. Ive never had it happen.

I was watching it, then all of a sudden a bunch of lines and garbled sound with hum just wrecked into the TV, and then the horiz clapsed, and the vert collapsed. so I look back there, seen half the filiment strings gone, and the other tube super super bright. I killed the power then.

...

I had a NEW 35L6 audio out tube develop a short like that after only being in the radio for a week. Being that the heaters were in a string, they lit up like a 60 watt light bulb! The sound from the radio made me think it was about to explode!

I brought the tube back to the store and they gladly gave me a new one.

Mike, I found a 12SN7 in the garage earlier... i'll send it to ya, but it won't go out till Monday.

ok. Thanks!

I wonder why it just all of a sudden did that.


hmm.

thanks for the tube charlie! i got it. but.

OUt to the beep trash this peice of beep TV goes.

now its even more fucked up. The sound is so hard to describe, there is no audio. just fuz popping in and out (oscillating fuz). there is HV, and the osc circuits are working. but now there is no raster.


Im so fucking pissed i cant see streight. Ive NEVER had this many problems with a TV before in my life.

sorry for the language, if you havent noticed already, I have a short fuse, and it blows alot.


that last .005 all the way at the end by the flyback may have gone south (that metal can one). I heard momentary arcing for a sec or to, and it stopped.

now there isnt a raster, and no sound, but static in the speaker popping in and out like a clock.

OMG.

I pull it all out of the cabnet. it works.


go figure. maybe something got shorted.

Sweet Jesus! I've been on the edge of my seat thru this whole ordeal and fell off of it when you said you had tossed the set.......now I'm back on the chair with my butt firmly planted.

YAY! Am glad that you were able to cool off and discover this latest thing, it's similar to when I'm repairing a car......I'll get frustrated and pissed causing me to cuss up a blue streak and toss tools around. Then I'll storm away only to cool off while the entire time I've got it in the back of my mind, allowing the subconscious to figure it out.

Sometimes I'll leave it be to the next day and actually dream of the fix! No foolin, guess I'm channeling Edgar Cayce LOL!

Anthony

Does this set have the metal plate covering the bottom?
If so something might be arcing to it.

nope.

I was darn tempted to toss it out the window.

but, it works outside the cabinet. maybe something was shorting when it was cramped into the cabnet. I dunno.

Oh, these little Motorolas are cute but infuriating. I have one with a typically shot 7JP4, and to add to the fun, it randomly dead shorts or blows out rectifier diodes in the PS. No rhyme/reason to it. It's not an HK short on the CRT, I once put a transformer supply to the heater and gave it about 15V and got a respectable picture.

I'd say next to the Predictas, these things have to be the worst sets out there to get going, but they're so darn cute....

Vertyical lin troubles got me, too. So I'm getting some ideas here on what to look into when I decide to tackle mine again.

Not working when you put it in its cabinet... With it on the bench working, try carefully twisting the chassis a little, and various portions of the chassis up top (being careful of voltages and hot tubes). You might be able to find a bad connection or loose tube or such. This can be agravating.....:mad:

thanks to all that helped! you requested it, so here ya go!

Hot damn! He's cookin' with gas now!

Congrats, Mike! I know you're glad it's finally over! So what turned out to be the problem when you would put it back in the cabinet?

I've always wanted one of those Motors. I like that one over the "suitcase" model.

Drinkin a beer for ya dude!

:yippy: :banana: :banana: :grnbounce :banana: :banana: :yippy:
:boink: :bigok: :banana: :bigok: :boink::bigok: :banana: :bigok:

That's fantabulous! Now if you could only get the color working. :uzi: :p:

Anthony

What would be wrong with the color?

oh yea. its NOT A COLOR CRT. lol hehe.

and no color circuitry.

I dunno, it worked outside the cabinet. I put it back into the cabinet, and it works. so o well. maybe a wire was touching. hel, I cant reproduce it, and ill be dammed if I want to. lol.