Nicktronic
Badcaps Veteran
Last Activity: Yesterday, 07:49 PM
Joined: 03-05-2023
Location: Lower Sackville, NS
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I used isopropyl, a brush and a plastic spudger. All components tested good. Cathode of DM807 on power up was 5.45VDC slowly discharging at a rate of 0.01vdc/second... -
All the SMD resistors test fine as far as I can tell.Leave a comment:
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I can't see a resistor under the legs, only jumpers....
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Yes, it was shorted D to S. Where is the shunt resistor? Is it on the underside of the board, or under the heatsink?...Leave a comment:
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Just to be clear you are talking about QP801/802 and not QM801/802?
I've attached cleaned up pictures.
I tested all diodes and MOSFETs on the board and all are good, still no standby voltage....Leave a comment:
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QP801CS - source to neg - 0.24 ohms
QP802CS - source to neg - 0.24 ohms
QM802CS - source to neg - 0.22 ohms...Leave a comment:
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QP801CS (new) - 167vdc
QP802CS (new) - 167vdc
QM801CS - 125vdc
QM802CS - 8vdc...Leave a comment:
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No, I pulled it and tested it. Was like 93uF (it's 100uf rated). I suppose I could test it with DC supply and put 50VDC on it (it's a 63vdc cap)...Leave a comment:
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I'm at a loss....everything I've checked seems ok, but I'm having trouble following the circuit to understand exactly where the 10VDC (that should be 14-29) is sourced from. It appears to start tapped off that big transformer and through a diode, but how is the TXFMR producing V without any switching happening. Does anybody have a schematic close to BN44-00874F?? Can anybody confirm that this board should be fully on when on the bench (like other samsung power supply boards), or do I need to install it?Leave a comment:
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Rechecked, they are good and the same....Leave a comment:
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Checks out ok, no shorts...Leave a comment:
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Yes lotas, this is exactly what I did to start the repair. But I'm still having this issue. I will check again though......Leave a comment:
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With power applied on the bench, CM814 and CM815 have 10VDC, equal to the VCC of ICM801S, but CM810 reads 0VDC. Not sure what role it exactly plays, but there should be something right? Sure would love a schematic! 😬...
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They test good.
Which resistors? I've checked all the through ones and think they're ok....Leave a comment:
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Thank you all, I will check tomorrow.Leave a comment:
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I will. Is there any chance it could be the FA6B22N?? I was saying that there was 7 volts on the FB line, but am not sure if that is normal or possibly is keeping the IC from fully operating...Leave a comment:
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Did already, they are good....Leave a comment:
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Let me know if these are sufficient...
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