Toshiba 42HL196 - Clicking relay, Power Board

[MEB]

Got one of these from the recycle center. The back cover had a hole in it and one of the boards was broken, but it was cheap. I didn't hear any glass rattling around so what the heck. I took the back off and the only real damage so far was the broken board. It was the Low B from the manual. I found 1 for 13 bucks on ebay. When I got the board, I replaced it and fired her up. I had the 3 red blinks which everyone here seemed to get so I broke down and bought and replaced Q820, Q860 and Q880 like most posts seemed to suggest. Now when I tried it out after replacing those parts, I get no red LED, but I get the relay clicking like budm described in his post. So I think I will attempt to remove the board and do what he suggested in his post to troubleshoot the board. I am going to take some pictures and will be back, but if anyone wants to chime in with the limited information I have given so far, be my guest. I haven't worked on many TVs, but this one is better than I have at home so I have high hopes.
OK, I hooked up the board like budm showed and it is trying to run. I don't know much about electronics but am trying to follow page 3 of the schematics for the PE0071 power supply board.

I believe it is relay SR80 on the board that is doing the clicking. It does so repeatedly every .5 seconds. If I put the meter on the 5V and Gnd at PB809B where budm had me put in those resistors, the meter cycles between 0V and 5V DC correlating to the clicks of the relay. He checked PFC voltage booster circuit. If I am on the right spot (across C821) I only get 160 VDC. At Q820 which I had replaced I get 0V at pin7 and a cycling 0-2.1 VDC at pin6going up and down in sync with the relay clicking.

I will be going back in to try to do more, but I really could use some guidance at this point. This is where I normally get into trouble as I don't know what I am doing.

[MEB]

Re: Toshiba 42HL196 - Clicking relay, Power Board

Still have the PE0071 power board problem. Board is out and jumpered on for troubleshooting. I am really at a dead end. Been snooping around but don't know what else to do. Anxious for any help.

[MEB]

Re: Toshiba 42HL196 - Clicking relay, Power Board

Hello BadCaps,
I need guidance. I am confident this problem involves simple electronic theory, but since I have not received any for over 4 decades, please cut me some slack.
From my original posts I have a Toshiba 42HL196 I am trying to fix. As previously stated I have replaced the 3 common parts which eliminated the 3 blinks, but didn't rectify the situation.
Today I spent an enormous amount of time to reveal the following information. I believe the answer is here, but I need help. Please see the attached drawings for details.
On the PE0071 Power Board, the 5 Volt relay clicks on/off every ½ second. If measured the 5 volts goes between 0 and 5 VDC in sync with the relay clicks. With the board in its original configuration, see details on attached Cond. 1.. I do have the board on the table and it is jumpered on as budm showed me to do.
I removed both the 5V and 12V relay as I couldn't tell what was clicking and tested them both with a Power Supply. Both appeared to function normally and cycled my ohm meter attached in sync with the clicks. I put the coil side only of the 5V relay back in its holes. See new details on attached Cond. 2..
Finally, I removed the 5V relay completely from the board. See attached Cond. 3..
This is over my head, and I could use some direction please.

[MEB]

Re: Toshiba 42HL196 - Clicking relay, Power Board

I guess I will replace the coil. Don't see how that could be it, but will find out.

[MEB]

Re: Toshiba 42HL196 - Clicking relay, Power Board

Still need advice, but in the meantime I ordered a replacement relay. Don't really think that is it but will learn something for next time.

[mmartell]

Re: Toshiba 42HL196 - Clicking relay, Power Board

The power supply is likely seeing something it doesn't like and is restarting. Probably not the relay. Maybe this little bump will help you though

[MEB]

Re: Toshiba 42HL196 - Clicking relay, Power Board

thanks for the idea. I will start snooping around the 5v circuit to see if I can find anything. thanks again.

[MEB]

Re: Toshiba 42HL196 - Clicking relay, Power Board

OK, I am agreeing with mmartell and believe the 5V relay is not the problem. I guess I will have some spares when they get here. With the relay in, I get repeated clicking, with the relay out, I get solid 5V DC, but if I measure current in the circuit with the relay removed, the current is fluctuating from 0 - 62 mA in sync with the interval of time as the relay clicked when in circuit. So in layman thinking, the 5V circuitry is trying to achieve a constant 5V output, but something is shutting it down due to the current reaching a limit or which is too high for one of the other components in the circuit which starts the whole scenario over again. If that thinking is at all correct, what could be causing that and where would one start to look?

[KevinCro]

Re: Toshiba 42HL196 - Clicking relay, Power Board

Are you testing the board while it is connected to other parts of the television?

[budm]

Re: Toshiba 42HL196 - Clicking relay, Power Board

OK, remove those two force on resistors (5V and POWER, 5V and Power_signal), then put 10 Ohms 5W resistor on the 5V1 and GND to see if the 5V1 will be stable or not. SCH page 20 for STBY 5V1 power supply.
If it is not stable, then you need to check the startup caps C845 (22uF 50V), C8403 (47uF 50V). C840 (47uF 450V) should also be checked.
https://www.badcaps.net/forum/showth...196#post507565

[MEB]

Re: Toshiba 42HL196 - Clicking relay, Power Board

Thanks KevinCro and budm - board is out as per thread by budm, see "Toshiba 42HL196 repair" sorry I don't know how to link it here.

budm - I will do exactly as you say and post results back. Thank you. Probably won't get it done till later today.

[MEB]

Re: Toshiba 42HL196 - Clicking relay, Power Board

OK, I think I must be doing something wrong. I had the 12V and 5V relays out, so I put them back in. I removed the 2 force on resistors like you said. I found a 10 ohm, 7W resistor at a part's house and connected it to 5V1 and GND like you said. I connected it at P809B. AC is still hardwired in directly on the board as before and the board is still on the table. Upon plugging into AC, I get 0V DC where I expected to get 5. I went ahead and checked C845, C8403 and C840 in circuit and they seemed fine. I had some spares so I went ahead and installed new Panasonics in C845 and C8403. I had no big one so I removed C840 and ESR = .63 and value was 42.5uF. I put it back in and still 0V DC. I was going to remove the 10 ohm resistor and re-attach the force on ones to make sure nothing changed but I figured it best to await further instruction.

[budm]

Re: Toshiba 42HL196 - Clicking relay, Power Board

That 5V1 should be there all the time, that is an always on power supply.
What voltage do you get at the two legs of C840 (47UF 450V)?

[MEB]

Re: Toshiba 42HL196 - Clicking relay, Power Board

I get 159-160V DC. Thank you.

[budm]

Re: Toshiba 42HL196 - Clicking relay, Power Board

OK, so it has Voltage for it to run but it is not working. I do not know what went out, I will have to look at the diagram to see what is going on.

[MEB]

Re: Toshiba 42HL196 - Clicking relay, Power Board

Thank you. In the meantime I will go look around to make sure I don't see anything I may have created.

[MEB]

Re: Toshiba 42HL196 - Clicking relay, Power Board

I turned the board over and checked my soldering and polarity,etc of the new caps and found nothing wrong. I powered up the board again and I have 5.091V DC very steady at P809B. So maybe an intermittant or I goofed! Sorry.

[MEB]

Re: Toshiba 42HL196 - Clicking relay, Power Board

OK, I watched my meter, unplugged and plugged in AC many times, turned the board over and back many times, tapped on every component on the board many times and everything I could get away with and the voltage never fluctuated off of 5.091V DC when AC was on. I have let it run for about half an hour and it is still steady. Either I did something stupid or I'll see this again, but I want to let this run over night and if I don't hear back any different, I will try to force on the board again and see what the relay sounds like again. Sorry if I sent you on a wild goose chase.

[budm]

Re: Toshiba 42HL196 - Clicking relay, Power Board

I would put on the resistor load and see if it can handle 0.5A of load current again.

[MEB]

Re: Toshiba 42HL196 - Clicking relay, Power Board

The 10 ohm resistor is still on there. Is that the load you mean or do you mean to force the board on again?