Can someone confirm what should attach to the selenium rectifiers? Someone replaced mine but there are a lot of loose connections and I'm not sure what goes where. The schematics don't match the spare chassis I have (TS-4J as well).

Thanks,
Zach

I've restored several of these and the published schematics are correct. What differences are you seeing in your spare chassis ?

I've restored several of these and the published schematics are correct. What differences are you seeing in your spare chassis ?

Maybe I'm reading this wrong, but the positives of C2A and C1 should never touch right?
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This is the actual wiring of the spare. I realize this isn't in proper schematic form, but I didn't wanna confuse myself.

Right the positives do not touch - the rectifier goes in between. Your spare isn't wired right. Maybe someone was trying to fix it ?

We can only guess. The spare had numerous evident repairs. It blew both the diodes when I installed it in the main chassis, but hopefully all of the caps are still within tolerance.

We can only guess. The spare had numerous evident repairs. It blew both the diodes when I installed it in the main chassis, but hopefully all of the caps are still within tolerance.

If the caps you mention you hope are still good, then if they are original they won't be.

If the caps you mention you hope are still good, then if they are original they won't be.

Even if those caps are new if the wiring errors put reverse polarity or AC across any of those caps the ones that got it are done for.

Even if those caps are new if the wiring errors put reverse polarity or AC across any of those caps the ones that got it are done for.
And if you don't take that into consideration, you may have headaches in the future. I realise it is difficult to throw away a "new" capacitor. But they are really not that expensive and there is security in knowing that they are new, and not stressed.

Yeah, today I purchased new electrolytics for all but one of the caps.(The only two that tested good were either before the diodes, or not in the power circuit.) Since I elected to restuff, it should be fairly easy to replace them without unsoldering the whole can, just cutting and resoldering the leads. My parts store didn't have some of the values, so I'll have to make do with a few caps that are higher value (eg a 150uF instead of a 120uF) but it should be alright until I get permanent replacements.

Well this is intresting, the tubes failed to light, but then I found out that the grounds on the caps weren't connecting properly. After a quick fix, still no high voltage, but all of the tubes were once again lighting properly. When I test the Caps after a quick power on they test alright, but after sitting for some time they test way out of specs. What keeps blowing my caps? How do I troubleshoot this? Both of the diodes appear to have shorted once again as well.

Start from scratch with the schematic. There are 2 diodes, maybe one was put in backwards. The grounds go to different places so they cannot be tied together. IIRC one cathode end of one diode goes to the ballast, pin5 , and the other to pin 4 of the ballast provided you are using the correct ballast . The cathode end of the diode going to pin 5 now continues to the positive end of the second diode. Check that schematic it's all there as it could be a simple mistake or a wire in the wrong place. I have 7 of these sets and had my share of stupid mistakes. :smoke:

http://www.videokarma.org/attachment.php?attachmentid=197382&d=1531347472

I might have found the culprit. If C79 has failed that would be enough to short the circuit, right? Its capacitance is way off and it tests at 190ohms. What type of cap should I replace this with and with what voltage?

If C79 shorted the 200 ohm part of the ballast resistor should of burned up very quickly.

If C79 shorted the 200 ohm part of the ballast resistor should of burned up very quickly.

If that isn't the case, if anything at all had shorted, then the ballast should be blown right?

What should the voltage coming off of pin 4 and pin 3 be?

I don't find a c79 power supply cap on the ts4j schematic.

:scratch2:If that isn't the case, if anything at all had shorted, then the ballast should be blown right?

What should the voltage coming off of pin 4 and pin 3 be?
Almost full line voltage because of no load.
That set's a little trickier to troubleshoot because it uses a floating B- line instead of a hot chassis. :scratch2:

I don't find a c79 power supply cap on the ts4j schematic.
I think he meant C97.
I just spent a half hour trying to find the B+ source. It seems it's sourced from the cathode of the 12SN7, 2nd clipper.
Slightly harder schematic to understand! Even the Sams isn't much better.

I think he meant C97.
I just spent a half hour trying to find the B+ source. It seems it's sourced from the cathode of the 12SN7, 2nd clipper.
Slightly harder schematic to understand! Even the Sams isn't much better.

The TS-4 family created the B+ rail by using several stages between B++ and B- as a voltage divider. You know how some makes used the audio output as a voltage dropper instead of a resistor...Moto took it a step farther by using several tubes in series-parallel to make a voltage divider. Crazy but it worked.

The TS-4 family created the B+ rail by using several stages between B++ and B- as a voltage divider. You know how some makes used the audio output as a voltage dropper instead of a resistor...Moto took it a step farther by using several tubes in series-parallel to make a voltage divider. Crazy but it worked.
And later with the ts18 they used half of the I think it was the audio amp for the verticle oscillator, well they had there ways back in the day. :yes:

I think he meant C97.
I just spent a half hour trying to find the B+ source. It seems it's sourced from the cathode of the 12SN7, 2nd clipper.
Slightly harder schematic to understand! Even the Sams isn't much better.

I was referring to C79 on the SAMs schematic(TS-4J Late). It's a little rf bypass connected to pin 3 on the ballast though it's located right behind the tuner.

The TS-4 family created the B+ rail by using several stages between B++ and B- as a voltage divider. You know how some makes used the audio output as a voltage dropper instead of a resistor...Moto took it a step farther by using several tubes in series-parallel to make a voltage divider. Crazy but it worked.
It only seemed to be the 12SN7 feed and I didn't explore the rest of the circuit to determine the rest of the voltage divider circuit. :scratch2:

So, does anyone have any good tips to keep troubleshooting? I've gone through the schematics up through the power supply, but haven't really checked much else.

What exactly is wrong tubes won't light, caps won't charge to proper voltage ?

Tubes light for about 30 sec and then they sorta flicker on and off and there's still something causing my caps to fry as well. The filament circuit problem is just caused by the faulty electrolytic caps, but I can't figure out what causes my electrolytics to fail in the first place. Some of the caps that were around 10-20uF are now testing in the hundreds range.

The filament circuit should not be affected for the caps. There are two series filament strings that connect directly to the AC line through a ballast resistor.

Sounds like there is a problem in the voltage double B++ supply that is shorting out the AC line.

Note that none of the negative leads of the electrolytics connect to the chassis. The chassis is floating in this set - it is not common. Also make sure your diodes are not installed backwards.

Also I'm wondering about the values of the caps you're using. There should be a 140, 120 and 100 uF cap in the B++ supply circuit - nothing in the 10-20 range.

There are 2 smaller caps in the circuit not the power supply so if they are going bad then it almost sounds like ac is getting into the DC circuit. I would stop and go over the schematic with a fine tooth comb and start at the diodes as bandersen noted that the b- does not go to the chassis at all. If the diodes were backwards you may get nothing but if one is backwards then you would have a problem, sort of maybe having DC on one side and ac on the other which should not be. The filiment string should not be dependant on an electrolytic cap the ac would distroy the cap . If it were then as soon as the cap takes a dump so does the filiment string, goes out. :yes:

I noticed that C-45 in the Sams schematic you posted does not match the Motorola factory issued schematic for a TS-4J late model. The ground end of C-45 should be connected to the floating B- line, not chassis ground. Also if you are using an original metal can ballast, make sure that it does not have any internal shorts. Remove the ballast if you have to, and check the pins for proper continuity and resistance. Your set is supposed to use the latter ballast, as shown in the schematic you posted. A ballast with internal shorts will cause all kinds of problems.
Ed

C-45 in the Sams is going to B-. B- is represented by the taper horizontal line symbol. Chassis is represented by the symbol with diagonal lines I circled at the top.

https://farm1.staticflickr.com/927/43419878742_f4ebd5321b_c.jpg (https://flic.kr/p/299See1)

Also I'm wondering about the values of the caps you're using. There should be a 140, 120 and 100 uF cap in the B++ supply circuit - nothing in the 10-20 range.

Yes, I recognise that the B++ power supply doesn't use any, however upstream in the audio circuit, the electrolytics are getting blown because they connect to the B++

I noticed that C-45 in the Sams schematic you posted does not match the Motorola factory issued schematic for a TS-4J late model. The ground end of C-45 should be connected to the floating B- line, not chassis ground. Also if you are using an original metal can ballast, make sure that it does not have any internal shorts. Remove the ballast if you have to, and check the pins for proper continuity and resistance. Your set is supposed to use the latter ballast, as shown in the schematic you posted. A ballast with internal shorts will cause all kinds of problems.
Ed
I'm using a glass ballast resistor that came with the spare chassis. It matches the pinouts of what I need. Which schematic would be the correct? I saw there was one on the ETF website that I think is more correct.

I can't check it today, (Adding a new rack to the workbench) but I'm almost positive I connected the output of the capacitors directly to the chassis. This whole floating chassis thing is a real pain in the neck.

Definitely do not connect anything to the chassis.

Yes, I recognise that the B++ power supply doesn't use any, however upstream in the audio circuit, the electrolytics are getting blown because they connect to the B++


Ah, that's weird. What caps do you mean exactly? There are two electrolytics in the audio circuit and neither goes to B++.

If you mean the 20uF cathode bypass on the audio output tube, it should only have about 9 volts across it. Perhaps that 25L6 has a short or is miss wired ?

The other is a 10uF in the FM ratio detector that should only have a few volts across it as well.

C-45 in the Sams is going to B-. B- is represented by the taper horizontal line symbol. Chassis is represented by the symbol with diagonal lines I circled at the top.

https://farm1.staticflickr.com/927/43419878742_f4ebd5321b_c.jpg (https://flic.kr/p/299See1)

Your right Bob, I didn't catch the top symbol you circled for ground, Sams' had their own notation. With the correction you noted, then leaves some of the filament bypass caps in the set incorrectly grounded. I'm using the Wallaces' Motorola book which show C-18,24,27,28,33,79 and 80 to chassis ground. I used sams folder 71-12 to cross check. Zsuttle should probably use the riders schematic from the ETF. It would probably be more accurate.
Ed
I did some more checking today, it seems the ETF Riders schematic for the TS-4J is for the early version. I added a picture of the schematic for the late version power and filament supply.

Added a schematic to the previous post.

Definitely do not connect anything to the chassis.




Ah, that's weird. What caps do you mean exactly? There are two electrolytics in the audio circuit and neither goes to B++.

If you mean the 20uF cathode bypass on the audio output tube, it should only have about 9 volts across it. Perhaps that 25L6 has a short or is miss wired ?

The other is a 10uF in the FM ratio detector that should only have a few volts across it as well.

Ah, my mistake, I glanced at the A and assumed it was from the power supply when I was looking things over.


Your right Bob, I didn't catch the top symbol you circled for ground, Sams' had their own notation. With the correction you noted, then leaves some of the filament bypass caps in the set incorrectly grounded. I'm using the Wallaces' Motorola book which show C-18,24,27,28,33,79 and 80 to chassis ground. I used sams folder 71-12 to cross check. Zsuttle should probably use the riders schematic from the ETF. It would probably be more accurate.
Ed
I did some more checking today, it seems the ETF Riders schematic for the TS-4J is for the early version. I added a picture of the schematic for the late version power and filament supply.

I see that the SAMs has a few mistakes. Where can I get the full schematic from? I'm still tracing out the power supply using the new schematics and all. Also, just wondering what's the difference between the Late and Early versions?

You can download Motorola service info from the Early TV Foundation here: http://www.earlytelevision.org/tv_schematic_diagrams_motorola.html

I belivebe the only mistake with the Sams is showing some of the filament bypass caps going to B- when they should be the chassis.

They changed the ballast tube and the contrast control circuit from the early to late TS-4J. There may be other very minor differences. The power supply circuit is the same.

Alright, I've gone over the schematic with a fine tooth comb and determined that every component is in its proper place. (I'll give it to Motorola to make things difficult) Both diodes were installed correctly and the same with all of the caps. Any advice?

Alright, I've gone over the schematic with a fine tooth comb and determined that every component is in its proper place. (I'll give it to Motorola to make things difficult) Both diodes were installed correctly and the same with all of the caps. Any advice?
If all you are saying that diodes and caps are correctly installed then it may be a good idea to trace the ac to find out if any part of the ac was moved in the filiment string to any of the b+ and or b++ by accident or simply a mistake. The only place in the DC circuit that will have ac would be on one side of the diodes to change ac to DC .

Another thing to beware is heater to cathode shorts...
Also, you are sure your diodes are installed correctly, right?... May want to double check with a DMM in DC volts mode connected between B++ and B- during power up...

It may also be worth checking to chassis ground because who knows what was done to the chassis already and what may have been bad or shorted out already like possibly the filiment caps to ground or maybe a carbonized .470 resistor to chassis. It is a stretch but being the problem is becoming a headache, why not.

Well I can definitely confirm that some of the caps going to chassis have shorted. Curious, because on my meter they still show the proper capacitance, however the resistance is just a few ohms. I think this could be the issue causing the diodes to blow. Still on vacation, once I return I’ll be able to tell if that’s been the only problem.

Cheers,
Zach

You have to lift one leg of the capacitor befor you check capacitance or ohms.

You have to lift one leg of the capacitor befor you check capacitance or ohms.

Yeah, I’ve made a habit of doing that or completely removing components to test them

Alright, well finally managed to get a HV up and running as well as isolate a short. I was able to get a decent picture as well, though it has a slight horizontal jitter. Any thoughts? What's the best way to isolate the source?

Besides the few size adjustments, not too bad.
198235

I have 6 of these Motorola sets and 2 of them are ts4j chassis and it don't matter early or late, there are Micas in the horizontal and verticle change them you may be surprised at the result as I was with my sets as all my sets but 2 I had to change the Micas in both horiz and vert , they were bad. I had jitters from both sides of deflection as well as verticle would not lock to the horizontal not being right. OH and also look into resistors around the verticle and horizontal circuits they will probably be out of tolerance .

The test pattern looks good.:thmbsp: Glad to see you stuck with it on the TS-4J. You may want to try swapping tubes for the horizontal oscillator and afc tube. Maybe corroded sockets and ground connections, rivets. Try the easy solutions first.
Ed

Tried swapping tubes and cleaning a little bit to no avail. I don't have many mica caps, so I'll have to order them. Hopefully that should work.

Thanks all,
Zach

You will see in the schematic the values of the Micas, IIRC there a couple of 100mmf and I think one 250mmf but check the schematic. What did you use for the hv defection caps.

You will see in the schematic the values of the Micas, IIRC there a couple of 100mmf and I think one 250mmf but check the schematic. What did you use for the hv defection caps.

I used .0047 and .001 film caps at 6kv (From JustRadios)



Well, got the new caps and replaced most of the components in both the vertical and horizontal sections. There's still a significant jitter, and the picture quality appears to be getting worse the longer I troubleshoot. Any ideas?

Hi,
What kind of jitter are you seeing, vertical or horizontal? Many of the tv's and radio equipment I repair have flaky potentiometers. They can be a source of erratic operation. A little electrical contact spray helps sometimes.
Ed

I've had Tin whisker issues in pots in TS-4 Motos before. Also the Mica caps in the sweep can be problematic.

I changed the value of the resistor on the wiper of the vertical lock form 3.3m to 4.7m and was able to get a lock on the vertical. However, by replacing other components, the image now looks like this and this.
198278
198279

I think it's something in the video sections affecting the sync signal before it gets stripped?

I've replaced most of the components in the vertical and horizontal sections, though that's made the video worse than what it was before.

There is also a mica under the 12sn7, horizontal sweep, don't know if you changed that one but if you didn't be careful when changing make sure it's the right value and don't make a mistake putting the legs back in the correct position otherwise the horiz won't run and it will burn up the horiz hold pot. At one point I had changed the resistor to get vert to lock only to realize that I missed a mica in the verticle section and once changed I put back the right resistor and it was fine. Look in the schematic at the vert and horiz section and write down all the caps that are marked MMF those are the ones to change. The one under the horiz tube looks like a dogbone. Although some look like dog bones and others look like a domino.

Just for the heck of it run the set and turn the horiz hold pot all the way to one end then start back to get the best pic because you can get a pic but will have distortion if turned to much in the opposite position, it's happened to me .

Ive recapped my VT71 and it has a case of slight horizontal and vertical jitters. then again, every tv where i use the dvd plaver has the same jitter issue. i wish i had ann over the air signal to use. maybe it the video source causing the jitters

Ive recapped my VT71 and it has a case of slight horizontal and vertical jitters. then again, every tv where i use the dvd plaver has the same jitter issue. i wish i had ann over the air signal to use. maybe it the video source causing the jittersdid you try one of those 75-300 ohm transformers where it has the threads on one end and the 2 wires on the other, that's what I use and it's perfect.

Well, I had replaced all of the caps in the sweep circuits. Later today I'll try injecting a composite signal and seeing where that gets me.

~Zach

Well, I had replaced all of the caps in the sweep circuits. Later today I'll try injecting a composite signal and seeing where that gets me.

~Zach
It may be possible that the alignment is out just a little, if you check the schematic you can very slightly move the channel 3 adjustment on top of the chassis, but do make sure you have a good signal to start with.

Well, tried injecting a signal, couldn't get it to go through the way I wanted. I've combed over the horizontal, vertical, and sync and cannot seem to locate the problem. Is it possible that it's emanating from earlier in the circuit in one of the video sections? The picture appears darkened and has the horizontal jitter. The frame is not centered all of the way, with a little black bar at the bottom.

More pics.. You said the pic is on the dark side and Alittle jittery, have you checked the contrast/ agc adjustment on the front right. There may be 2 caps off that pot, maybe check them.

May want to scope the sync separator...if it is letting video or noise through that could be freaking out the sweep.

More pics.. You said the pic is on the dark side and Alittle jittery, have you checked the contrast/ agc adjustment on the front right. There may be 2 caps off that pot, maybe check them.

It could be, the when the contrast is all of the way up, the picture goes out of control. I'll replace the three that are there. EDIT: I was able to successfully get the picture back to normal by replacing the three capacitors around the contrast control. However, the slight shudder is still there along with the uncontrollableness created by turning the contrast or brightness to full.

May want to scope the sync separator...if it is letting video or noise through that could be freaking out the sweep.

Not entirely sure what to look for, however, here's the output of the plate on the sync. Hopefully that helps.

198290


I've also purchased a TV analyst for troubleshooting, seems like a useful tool. WOn't be here for another week

Did you check resistors around each IF tube because my sets had several bad resistors around that area. Especially if you think it may be a signal problem.

Did you check resistors around each IF tube because my sets had several bad resistors around that area. Especially if you think it may be a signal problem.

Yeah, I'd already replaced a few that were double their resistance. Is there a specific way to figure out what section this is emanating from? I've noticed that the power supply has a decent ripple in it, how much is acceptable for a power supply like this?

It could be, the when the contrast is all of the way up, the picture goes out of control. I'll replace the three that are there. EDIT: I was able to successfully get the picture back to normal by replacing the three capacitors around the contrast control. However, the slight shudder is still there along with the uncontrollableness created by turning the contrast or brightness to full.



Not entirely sure what to look for, however, here's the output of the plate on the sync. Hopefully that helps.

198290


I've also purchased a TV analyst for troubleshooting, seems like a useful tool. WOn't be here for another week

That waveform looks pretty messy and weak...See if sams has a waveform and compare. If your sync pulses are messy you will trigger retrace mid line and other troublesome things like that.

That waveform looks pretty messy and weak...See if sams has a waveform and compare. If your sync pulses are messy you will trigger retrace mid line and other troublesome things like that.

http://www.earlytelevision.org/pdf/motorola_vt71_rider_tv1.pdf

ETF has the riders which has the waveforms in it on page 30. It's interesting to see that there's a 60hz signal on the sync output, that might explain the jittering. How much of a waveform should I realistically be getting on the power supply? I would have thought that the filter caps being as big as they are would have taken care of it.

http://www.earlytelevision.org/pdf/motorola_vt71_rider_tv1.pdf

ETF has the riders which has the waveforms in it on page 30. It's interesting to see that there's a 60hz signal on the sync output, that might explain the jittering.

There should be 60Hz in the synch output. Vertical sweep IS 60Hz* and it needs 60Hz sync pulses.

*Granted color changed it to 59.9Hz, but rounding is a thing.

There is a resistor at v1 it's a 1k with b+ at the one end, just from my troubles with my sets double check that resistors value because I have had that resistor bad and even burned up.

Checked that, however I just realised that some of the caps that I installed in the horizontal are 500v mica caps when it calls for 2kv caps. That might explain a little of that. The two caps are C71 and C72 680pf and 900pf respectively. Do those need to be mica caps or can i use ceramic discs?

No don't use ceramic, and as for the voltage yes the cap may show 2k volts but the 500 volt works fine since all the Micas even the ones in the sweep section are 500 volts that I put in my sets and my sets work great with them. I don't think 2 k Micas are available anymore. To answer your question yes Micas belong in that section, the schematic shows mmf , that would be the Micas.

Do you have the high voltage cover in place? It can cause issues if it's not installed.

Do you have the high voltage cover in place? It can cause issues if it's not installed.

Yes, it's in place, I messed with it and the picture got worse so I think it's making a good connection to chassis.

Does the distortion of the picture slowly move vertically with respect to the picture? If it does, the source is likely 60hz power related, which is not quite in sync with the vertical frame rate.

jr

There is a high voltage filter capacitor to chassis ground which is a .001 6kv , was that one changed. It may or may not effect the quality of the picture but you never know. Can you at all figure out weather or not it's verticle or horizontal, it would help things a lot at this point. Just a crap shoot but there is a mica that is usually mounted under the terminal strip where the .01 caps are for the verticle and if it's under there it is well hidden and that one should be changed as I had lots of problems and found that one hiding under there and that cured the headache I had with one set I have. Just trying to toss things out there.

I'm thinking it's more some sort of external signal. For now I've put it back in the cabinet and I'll recheck it. One question though. Since this is a transformerless set, I assume the chassis is hot during operation right? and would justify a polarized power cord?

I'm thinking it's more some sort of external signal. For now I've put it back in the cabinet and I'll recheck it. One question though. Since this is a transformerless set, I assume the chassis is hot during operation right? and would justify a polarized power cord?
It wouldn't matter...

Oh, ok, nevermind then, I wasn't sure because I had measured line voltage from chassis to wall ground. Any reason for that?

Some of the crazy things they did back in the day would be illegal today, lol. Or UL wouldn't pass them as safe.

Oh, ok, nevermind then, I wasn't sure because I had measured line voltage from chassis to wall ground. Any reason for that?

The chassis is floating. Neither side of the AC line connects directly to it. One side does via a 470K resistor in parallel with a 0.05 uF cap if memory serves. I believe that is to provide a return path for RF.

Yes it is the RF return path but even though there is a.05 and 470k resistor, depending on what you may touch and the chassis there would be shock though, it has happened to me, not shocking, lol lol. I myself did measure line voltage from chassis to other areas of the set.

It could be, the when the contrast is all of the way up, the picture goes out of control. I'll replace the three that are there. EDIT: I was able to successfully get the picture back to normal by replacing the three capacitors around the contrast control. However, the slight shudder is still there along with the uncontrollableness created by turning the contrast or brightness to full.



Not entirely sure what to look for, however, here's the output of the plate on the sync. Hopefully that helps.

198290


I've also purchased a TV analyst for troubleshooting, seems like a useful tool. WOn't be here for another week

Does this screenshot of the manual help? I had the same problem with my set and discovered that I replaced the cap that parallels the primary side of that transformer with a higher value and it filtered out the horizontal sync pulse to almost nothing.