Motorola TS-4J
 

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 ?

Maybe I'm reading this wrong, but the positives of C2A and C1 should never touch right?
Attachment 197382

Attachment 197383
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.

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.

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...2&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 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: 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 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.

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 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.

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/927/4...ebd5321b_c.jpg

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'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.


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.

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.

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


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_sc..._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?

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.