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Search: Posts Made By: R_J
Forum: Troubleshooting TVs and Video Sources Yesterday, 07:05 PM
Replies: 55
Views: 696
Posted By R_J
Forum: Troubleshooting TVs and Video Sources Yesterday, 07:02 PM
Replies: 55
Views: 696
Posted By R_J
Forum: Troubleshooting TVs and Video Sources Yesterday, 04:24 PM
Replies: 55
Views: 696
Posted By R_J
Re: Samsung 50uhd8550 standby led pressing power button does not turn TV on

The 21 volts comes from that transformer, transformers produce A/C (in this case it is at around 30khz) then the diode rectifies it into DC. Did you check if that 21 volts stayed up when you shorted...
Forum: Troubleshooting TVs and Video Sources Yesterday, 11:48 AM
Replies: 55
Views: 696
Posted By R_J
Re: Samsung 50uhd8550 standby led pressing power button does not turn TV on

Check the diode, resistor etc. on that line from the standby transformer, that voltage should not be dropping, it is supplied by the standby transformer. Maybe check the voltage right at the diode...
Forum: Troubleshooting TVs and Video Sources Yesterday, 10:11 AM
Replies: 55
Views: 696
Posted By R_J
Re: Samsung 50uhd8550 standby led pressing power button does not turn TV on

Something is killing that 20 volts, Does the standby 5 volts stay up when you short pins 3 & 4 of the opto? or does it also drop
Forum: Troubleshooting TVs and Video Sources 12-03-2020, 08:25 PM
Replies: 55
Views: 696
Posted By R_J
Re: Samsung 50uhd8550 standby led pressing power button does not turn TV on

I think you have the pins on the opto coupler mixed up, The supply voltage that comes from the standby transformer connects to pin 4 of the opto, so there is no way for pin 3 to be higher than pin 4....
Forum: Troubleshooting TVs and Video Sources 12-03-2020, 06:18 PM
Replies: 14
Views: 523
Posted By R_J
Re: Samsung UA60H7000AW Power Supply

Is QP802C one of the fets that is driven by ICM801S? Did you check it before and it was ok?
Forum: Troubleshooting TVs and Video Sources 12-03-2020, 05:46 PM
Replies: 55
Views: 696
Posted By R_J
Re: Samsung 50uhd8550 standby led pressing power button does not turn TV on

The voltage on pin4 should be around 20v, when you short pin 4 to pin 3 what does this voltage do? Check if CS808 is shorted, something must be killing that voltage.
Forum: Troubleshooting TVs and Video Sources 12-03-2020, 05:21 PM
Replies: 55
Views: 696
Posted By R_J
Re: Samsung 50uhd8550 standby led pressing power button does not turn TV on

I guess it could be, but not likely, the opto should still supply close to the vcc supply voltage to the base. It could be something like a DXT651 (used on other boards)
Forum: Troubleshooting TVs and Video Sources 12-03-2020, 10:23 AM
Replies: 3
Views: 53
Posted By R_J
Re: Panasonic Dvd Vhs combi

Start by downloading the service manual and check the power supply voltages. Seems like it might be a communication issue between the mirco and eeprom. Try heating the eeprom ic7702
I also found...
Forum: Troubleshooting TVs and Video Sources 12-03-2020, 09:14 AM
Replies: 55
Views: 696
Posted By R_J
Re: Samsung 50uhd8550 standby led pressing power button does not turn TV on

What you can try is see if the opto PCS802S will turn on the VCC for the main ic, Monitor the voltage out of QS801 emitter (can be checked at JP1017 using JP1028 as hot ground) then using something...
Forum: Troubleshooting TVs and Video Sources 12-02-2020, 10:13 AM
Replies: 13
Views: 218
Posted By R_J
Forum: Troubleshooting TVs and Video Sources 12-01-2020, 01:22 PM
Replies: 55
Views: 696
Posted By R_J
Re: Samsung 50uhd8550 standby led pressing power button does not turn TV on

Check the cold side of the opto, This time use cold ground and check the voltage on pins 1 & 2 of PCS802S, In standby you should have voltage on pin 1 and aprox the same on pin 2, when forced on pin...
Forum: Troubleshooting TVs and Video Sources 12-01-2020, 11:18 AM
Replies: 35
Views: 299
Posted By R_J
Re: Vizio M65 C-1 power supply dead - NO standby voltage

I drew out the path on YOUR board, If you take a piece of wire and measure 0 volts on each end and 164 volts in the middle, where would that voltage come from? it can't be there so something was...
Forum: Troubleshooting TVs and Video Sources 12-01-2020, 11:05 AM
Replies: 11
Views: 184
Posted By R_J
Re: Hisense 55P6 - No power no standby

Check the resistors and diode in the gate drive of that mosfet, hopefully they are ok and it is only a bad fet.
Forum: Troubleshooting TVs and Video Sources 11-30-2020, 10:19 PM
Replies: 11
Views: 184
Posted By R_J
Re: Hisense 55P6 - No power no standby

VCC of 20v is normal, so the ic should at least be in burst mode, which would give some voltage on the secondary, It could be that the ic is bad and not driving the mosfets.
Forum: Troubleshooting TVs and Video Sources 11-30-2020, 10:00 PM
Replies: 55
Views: 696
Posted By R_J
Re: Samsung 50uhd8550 standby led pressing power button does not turn TV on

Yes it could be the opto, You could try swapping PCM801S and PCS802S, I believe they are the same. PCM801S I believe is for the backlights
Don't swap PCS801S as it is the feedback opto for the...
Forum: Troubleshooting TVs and Video Sources 11-30-2020, 09:45 PM
Replies: 35
Views: 299
Posted By R_J
Re: Vizio M65 C-1 power supply dead - NO standby voltage

Then how do you explain 164v on J952? If R9139 was open then one side would measure higher than 18v. I suspect you could have a short between J934 and hot ground?
Forum: Troubleshooting TVs and Video Sources 11-30-2020, 09:41 PM
Replies: 35
Views: 299
Posted By R_J
Re: Vizio M65 C-1 power supply dead - NO standby voltage

Your meter probes can't be getting a good connection, there is no way you can have 164v on J952 and 0 on J934. Look at the board, J952 connects to J934 and J934 connects to R9139 which you said had...
Forum: Troubleshooting TVs and Video Sources 11-30-2020, 09:31 PM
Replies: 55
Views: 696
Posted By R_J
Re: Samsung 50uhd8550 standby led pressing power button does not turn TV on

Well it could be that the zener is bad and zenering at about 10v or the optocoupler which when turned on should have the same voltage on pins 3 & 4.
The markings on the zener will tell you what the...
Forum: Troubleshooting TVs and Video Sources 11-30-2020, 09:18 PM
Replies: 35
Views: 299
Posted By R_J
Re: Vizio M65 C-1 power supply dead - NO standby voltage

The board should be the same, If you have 18.4v on R9139, then you should have it on J934, J952, J958, C9109+ and R9113
Forum: Troubleshooting TVs and Video Sources 11-30-2020, 09:06 PM
Replies: 35
Views: 299
Posted By R_J
Re: Vizio M65 C-1 power supply dead - NO standby voltage

ok, check at the next resistor in the string, R9138, then R9139, this voltage should be around 15vdc at R9139, this is the vcc start voltage for the ic9101. The voltage should drop after each resistor
Forum: Troubleshooting TVs and Video Sources 11-30-2020, 08:52 PM
Replies: 35
Views: 299
Posted By R_J
Re: Vizio M65 C-1 power supply dead - NO standby voltage

Turn the board so you can read ATTENTION: LIVE PARTS and J958 is below LIVE PARTS. (Top View) I point it out because sometimes people can't locate the jumper wires.

If you have 0 volts on J958,...
Forum: Troubleshooting TVs and Video Sources 11-30-2020, 08:28 PM
Replies: 35
Views: 299
Posted By R_J
Re: Vizio M65 C-1 power supply dead - NO standby voltage

So you are measuring ACROSS the resistor. this is not how to check this voltage. You must place the negative lead of your meter on hot ground, You can use the heatsink of DB9101 (HS9901) as hot...
Forum: Troubleshooting TVs and Video Sources 11-30-2020, 08:18 PM
Replies: 55
Views: 696
Posted By R_J
Re: Samsung 50uhd8550 standby led pressing power button does not turn TV on

It could be bad, How does DS811 check? It could be that the zener diode is bad. what are the markings on the zener?
Showing results 1 to 25 of 500

 
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