Re: Toshiba power supply 37LX96 repair
The next thing we're trying is putting a 4.7K resistor load on the 5V1 line.
MtnFrost
Member
Last Activity: 01-21-2015, 01:33 PM
Joined: 12-25-2014
Location: Colorado
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Re: Toshiba power supply 37LX96 repair
Still gone. I've gotten some sample readings around the board as we've been working through. I'll share them here. These are taken with 1K resistors from power and sig_power to ground on a workbench, out of the tv. When plugged in, after replacing Q840, the board takes about 10 seconds after the relay engages before the relay begins cycling.
Q840 pin 2 using pin 3 as hot ground: 21 VDC, cycling to 10 VDC with relay
Cathode of D842 - fluctuates between 167 and 162 VDC
Pin 5 of Q840 - fluctuates between 160-96 VDC...Leave a comment:
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Re: Toshiba power supply 37LX96 repair
Sorry bud for the delay - I am working with one of those online electricians to troubleshoot the board and accidentally blew out Q840 and a resistor. Had to wait forever since I have no local electronic parts supplier locally. After replacing those, we're back to square one, where the 5V relay is power cycling.Leave a comment:
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Re: Toshiba power supply 37LX96 repair
As it happens Radio Shack has nothing I need, so I have to wait until tomorrow to find a local electronic store. Let me know if you think I should get a different rated resistor for the load test. $#$ radio shack....Leave a comment:
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Re: Toshiba power supply 37LX96 repair
Okay, I'll remove them and put 10 Ohms 5W resistor on the 5V1 and GND. Thank you for the help. Have to run out to get one. Will report back. Thank you.Leave a comment:
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Re: Toshiba power supply 37LX96 repair
Checking voltage at C840, I'm getting 160-166 V DC. This seems to be in keeping with what we'd expect, based off that troubleshooting link posted further up. I'm also not getting 5V DC at the 5V-1 post at P809B - it fluctuates between nothing and .8 V, timed to the relay clicking....Last edited by MtnFrost; 12-28-2014, 01:12 PM.Leave a comment:
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Re: Toshiba power supply 37LX96 repair
So using my limited understanding of all things circuit board related, the clicking of the 5V relay is the relay closing, and then opening. So the driver circuit closes the relay, but the load side of the relay cannot sustain that closing, and the relay goes back to it's initial state. And then the driver circuit closes the relay again, and we keep repeating the process.
So the driver circuit is good, but the load side is not. Do I have that right? Thanks!Leave a comment:
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Re: Toshiba power supply 37LX96 repair
So I connected two 1K resistors from the power and power sig to ground, just to see what we'd get without any other board connected. Sure enough, the 5V relay is clicking on and off.Leave a comment:
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Re: Toshiba power supply 37LX96 repair
So I'm going to be using a resistor to connect the 5VSTBY to ground, right? I seem to remember someone posting a link to their test setup somewhere here.
Found the link - this setup?
[url]https://www.badcaps.net/forum/showthread.php?p=507565&highlight=Toshiba+42HL196#post507565[/url]
I take I don't need to hook up a 12v bulb for our testing purposes.Re: Toshiba power supply 37LX96 repa...member someoneLast edited by MtnFrost; 12-27-2014, 02:32 PM.Leave a comment:
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Re: Toshiba power supply 37LX96 repair
I read through the link - am I reading it right that there never was a solution?Leave a comment:
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Re: Toshiba power supply 37LX96 repair
Okay, definitely the 5V relay. I was able to visually confirm it.
Just a note on my background with electronics - I was a collector of pinball machines for several years, and that required I learn how to use a multimeter, solder and desolder, and learn core concepts of electronics to repair and troubleshoot the early solid state boards.
In short, I know I can repair this board, but greatly appreciate all help.Leave a comment:
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Re: Toshiba TV not powering on?
Started a separate thread here:
[url]https://www.badcaps.net/forum/showthread.php?p=514110#post514110[/url]Re: Toshiba TV not powering on?<br /...st514110[/url]Leave a comment:
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Re: Toshiba power supply 37LX96 repair
Thank you Bud for the SCH! I believe it's the 5V relay, though to be honest the two are so close to each other I'm having a hard time definitively telling which is clicking. I've included a pic of the board, front and back, for reference....Leave a comment:
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Toshiba power supply 37LX96 repair
Hi All, and hello!
I got a toshiba 37LX96 very cheap because the owners claimed it was good as long as it was kept plugged in, but if you unplugged it, they had to wait 3-4 days before they could plug it back in and have it work.
Starting from scratch, plugging it in revealed the three yellow flashes. So I replaced the three ICs normally associated with this issue - strz4479, strw6765, and srx2039. Visually checked the caps, nothing visibly bad.
Now plugging it back in and nothing flashes - the relays on the power board are cycling, click-click, click-click.... -
Re: Toshiba TV not powering on?
One last thing - anyone know where to unplug the seine board?Leave a comment:
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Re: Toshiba TV not powering on?
This is an old thread, but since I just acquired a Toshiba 37LX96 that won't turn on, but you can hear the relays on the power board cycling, I'd thought I'd resurrect it.
I have the exact same power board, and I replaced all three ICs normally suspect. strz4479, strw6765, and srx2039. Now I should say before I did this, the tv wouldn't come on, but would flash three yellow lights. After I replaced these ICs, no yellow lights, and now the relays click on off on off. The caps visually look alright.
I will test the caps properly....Leave a comment:
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