Toshiba 42HL196 - Clicking relay, Power Board

[abdekader]

Re: Toshiba 42HL196 - Clicking relay, Power Board

change all capacitors after it's working , i repaired it

if not working change PFC STR

[MEB]

Re: Toshiba 42HL196 - Clicking relay, Power Board

Hello, hey budm. I have been busy with this board and will update what I have done. Since we were having intermitttent activity involving the 5V always on portion of the power supply, I took a little magnifier and examined every component and solder joint. I resoldered everything that looked marginal, but nothing changed. I went ahead and replaced all the rest of the capacitors on the board, even the big ones with Rubycons and Panasonics. Still the same.

This is the current state of the board. It is on the table, I have 2-100 ohm resistors in parallel for the 12V load. I have a 10 ohm, 7W resistor for the 5V load. I have removed the force-on resistors as I can not obtain a steady 5V1. At one time I did have 5.091 steady at 5V1, but never since the soldering and capacitor change. The 5V1 standby voltage fluctuates from 0 - 4 volts or so which was causing the 5V relay to click on and off. I have removed R8310 to keep the relay from clicking.

It seems as though the board is trying to achieve 5V but continuously cycles. This continues for a period of minutes until it eventually stays at 0V. Removing AC for 10 minutes or so is required before the cycling resumes as if maybe heat related? I am currently looking at page 4 of the schematic and trying to understand Q840 and T840 as to what role they might have in this problem but do not have enough circuit knowledge. I have begun writing down some measurements when 0V and cycling V and will try to organize those to assist. Thanks in advance.

[MEB]

Re: Toshiba 42HL196 - Clicking relay, Power Board

Looking at page 4 of the schematic, which is where I am currently snooping around, there is a Q840 (STR-A6169) which I believe is involved to allow T840(TPW3565AS) to provide 5V. Yes, I am grasping at straws, but I don't know what else to do. Below are some voltage measuremnts at these 2 devices, which I am hoping will provide some insight to someone.

When I have the cycling 5V (0-4) up and down, I read:

Q840
Pin 2 (Vcc) fluctuating 10-16V
Pin 7,8 fluctuating 157-358 V
T840
Pin 2 fluctuating 157-358V

After I lose 5V, I read:

Q840
Pin 2 (Vcc) fluctuating 10-16V
Pin 7,8 stable 157.3V
T840
Pin 2 stable 157.5V

From Q840 data sheet, Vcc Turns on/off around the fluctuating 10-16 volt limits I receive so maybe if this was steady, I might not get the cycling 5V? I wish I understood more, but I could use some direction. Please comment if you will.

[CapLeaker]

Re: Toshiba 42HL196 - Clicking relay, Power Board

Just some stupid brain fart I got. By any chance you wouldn't have the power supply plugged into a light bulb in series as for protection in case of a short? What would happen is that when you turn on the power supply, the light bulb would light up and then the power supply shuts down and the process starts again.
I wonder if the two 100 Ohm resistors in parallel are still hocked up?

[budm]

Re: Toshiba 42HL196 - Clicking relay, Power Board

https://www.badcaps.net/forum/showpo...7&postcount=23
I look at the diagram again and see that 5V is rated at only 250mA not 1/2A as I thought so 10 Ohms loading is too much, it should be able to handle 20 Ohms load.

[MEB]

Re: Toshiba 42HL196 - Clicking relay, Power Board

Nope, no lightbulb and yes 100 ohms still hooked up. Thanks for the thought.

OK budm, thanks a million. Thought maybe you were tired of this old board. I will go get another 10 ohm resistor and report back in a little bit. I knew being too cheap to buy more than one would be a mistake.

[CapLeaker]

Re: Toshiba 42HL196 - Clicking relay, Power Board

remove those two 100 Ohm resistors and put a fuse in. I don't think you had blown fuses to start with?

[MEB]

Re: Toshiba 42HL196 - Clicking relay, Power Board

Capleaker, I must have confused you. All fuses are in. The parralelled 100 ohm resistors are in there to make an equivalent 50 Ohm load for the 12V circuit. They are still in there for now.

budm - things have changed as shown after adding another 10 ohms to the 5V load.

Q840
Pin 2 (Vcc) stable 28.59V
Pin 7,8 stable 421V
T840
Pin 2 solid 424V

5V1 to ground is now 4.987V

She is staying on thus far.

[CapLeaker]

Re: Toshiba 42HL196 - Clicking relay, Power Board

Yep, got confused with those resistors location... I hope you get it to work though after all this work!

[MEB]

Re: Toshiba 42HL196 - Clicking relay, Power Board

Thank you.

[audiofreak19]

Re: Toshiba 42HL196 - Clicking relay, Power Board

Yea these tv's are a pain in the ass to work on. I had one with same issue. To be able to still profit on the tv I ended up buying a power supply. Keep at it I wanna see how this turns out

[MEB]

Re: Toshiba 42HL196 - Clicking relay, Power Board

Thanks for the encouragement audiofreak19, I won't give up.

I got called back in to work so I didn't get to work with the board any more, but tomorrow I hope to have more information. I will solder R8310 back in, force on the board and see if that darn relay quits clicking. Thanks again budm.

[MEB]

Re: Toshiba 42HL196 - Clicking relay, Power Board

Couldn't stay away. Went to solder in that resistor and with magnifying glass in one hand, soldering iron in the other and dental pick in the 3rd, I shot that resistor off into space and can't find it. I know it is 22K SMD, but I don't have a clue what to order and know absolutely nothing about SMD. If someone reads this, would you please give me a part number from Mouser or Digi-Key? The schematic says CHIP, 1/20W 22K OHM J and I think it had 223 printed on it. Sorry, I'm an idiot.

[mmartell]

Re: Toshiba 42HL196 - Clicking relay, Power Board

I know it's small but i believe you can use a standard 22k 1/8w resistor in its place if you have one.

[MEB]

Re: Toshiba 42HL196 - Clicking relay, Power Board

Thanks mmartell. I don't have any and I don't think I want to solder 22 1Ks together as that is as close as I can get. I will run out and find one but I still would like to get a replacement SMD. I will read up and see if I can figure what to get. So this will be a temporary delay in the progress, but I will be back. Thanks to all.

[CapLeaker]

Re: Toshiba 42HL196 - Clicking relay, Power Board

Couldn't stay away. Went to solder in that resistor and with magnifying glass in one hand, soldering iron in the other and dental pick in the 3rd, I shot that resistor off into space and can't find it. I know it is 22K SMD, but I don't have a clue what to order and know absolutely nothing about SMD. If someone reads this, would you please give me a part number from Mouser or Digi-Key? The schematic says CHIP, 1/20W 22K OHM J and I think it had 223 printed on it. Sorry, I'm an idiot.

Digikey part number: RHM22KCBCT-ND
or this one : 541-22.0KAABCT-ND Vishay Dale CRCW020122K0FKED

Do one of these look similar?

[MEB]

Re: Toshiba 42HL196 - Clicking relay, Power Board

Thanks for the info, but I already ordered 100 each of CRCW060322K0FKEA and ERJ-3EKF2202V for a whopping $1.80. I did some reading and think those match the original case size and have a pretty good probability that I can get 1 out of 200 on the board. Man they are little. I am off to the local parts house to see if I can find a through hole to stick in there so I don't have to wait for those to arrive. Thanks again and maybe I will have more to report later this evening.

[MEB]

Re: Toshiba 42HL196 - Clicking relay, Power Board

OK, closest I could find at this time to 22K is a 25K which measures about 24.5K. I hope that is close enough and I soldered it in. Firing up the board I still have 5V standby, but as soon as I force on, the relay starts it rhythmic clicking. Assuming it is not the value of the resistor I added, it seems the board is still up to its old tricks. But I do now have 5V standby which is one good thing. I shut it down for now and am going to think about what to do. Please share any thoughts. Thanks.

[MEB]

Re: Toshiba 42HL196 - Clicking relay, Power Board

Alright, I decided it best to repeat all the steps budm had me do before we ran into the 5V standby cutting out. Now I have 20 ohm load in the 5V circuit, 50 ohms load in the 12V circuit and the force on resistors in. Repeating everything in the previous posts, when I get to post 29 and pull the D826 while monitoring 5V1 to Gnd, the 5V is now stable at 4.978 VDC. So now that will make sense to him. I think he was having me do that to show that removing Vcc to that Q820 might mean that something in that PFC circuit was causing trouble. Wish I knew what that means, but I will start by trying to find a datasheet for that SRX2039. I'll be back.

[MEB]

Re: Toshiba 42HL196 - Clicking relay, Power Board

Wish everyone was here right now, but especially budm cause I'd be buying beer for everyone. God, I love this place. Seriously, my life has changed for the better finding you guys. I'm hooked. I really don't know shit, but hanging out here makes me feel like I do.

Well anyway, I believe this board has been fixed. Yipee!! I started this by replacing the 3 ICs everyone suggested with this Toshiba and with bud steering, I finally suspected it must be Q820 which was one of the 3 I bought from ebay and replaced originally. Luckily I saved the original and ended up putting him back in tonight, and what the hell, it worked! Everything works, I have all voltages I should have and I am so fucking excited. Thanks to budm and all of you for providing the spark and audiofreak19 for keeping the fire going.

I'll let you know how the rest of the TV turns out.