Samsung PS42-Q97HD, power supply: BN44-00161A clicking ON and OFF

**dick_barton** · 07-21-2016, 05:22 AM

Re: Samsung PS42-Q97HD, power supply: BN44-00161A clicking ON and OFF

So diode readings on both and when leads reversed no reading. That's fine.
Did you look at what the repair kit contained to give you an idea of what to check?

**jczarniak** · 07-21-2016, 05:31 AM

Re: Samsung PS42-Q97HD, power supply: BN44-00161A clicking ON and OFF

Originally posted by dick_barton

So diode readings on both and when leads reversed no reading. That's fine.
Did you look at what the repair kit contained to give you an idea of what to check?

Yes.
So in my case, mosfets looks alright, checked resistors, looks fine, checked surface mounted diodes, one looks doggy.
Can i replace the diodes with any similar diode, for example not surface mounted?

**jczarniak** · 07-21-2016, 05:37 AM

Re: Samsung PS42-Q97HD, power supply: BN44-00161A clicking ON and OFF

Originally posted by jczarniak

Yes.
So in my case, mosfets looks alright, checked resistors, looks fine, checked surface mounted diodes, one looks doggy.
Can i replace the diodes with any similar diode, for example not surface mounted?

Are these two surface mounted diodes: DX803, DX804 so important?
Is this the reason why power supply clicks on and off?

**ReeceyBurger123** · 07-21-2016, 05:38 AM

Re: Samsung PS42-Q97HD, power supply: BN44-00161A clicking ON and OFF

Possibly you if the board has space for through hole type of not it might be hard to bend the leads to solder that type. Also whats the Pn of the diode ?

**jczarniak** · 07-21-2016, 05:38 AM

Re: Samsung PS42-Q97HD, power supply: BN44-00161A clicking ON and OFF

Originally posted by jczarniak

Are these two surface mounted diodes: DX803, DX804 so important?
Is this the reason why power supply clicks on and off?

Diodes removed, still same.

**jczarniak** · 07-21-2016, 05:39 AM

Re: Samsung PS42-Q97HD, power supply: BN44-00161A clicking ON and OFF

Originally posted by ReeceyBurger123

Possibly you if the board has space for through hole type of not it might be hard to bend the leads to solder that type. Also whats the Pn of the diode ?

Diodes: KDS181 , according to schematics

**ReeceyBurger123** · 07-21-2016, 05:41 AM

Re: Samsung PS42-Q97HD, power supply: BN44-00161A clicking ON and OFF

Is it showing shorted across it diodes will almost neevr fail open ?

**dick_barton** · 07-21-2016, 05:45 AM

Re: Samsung PS42-Q97HD, power supply: BN44-00161A clicking ON and OFF

Originally posted by jczarniak

Are these two surface mounted diodes: DX803, DX804 so important?

Yes the diodes are important and are part of the repair kit.

**jczarniak** · 07-21-2016, 05:50 AM

Re: Samsung PS42-Q97HD, power supply: BN44-00161A clicking ON and OFF

Originally posted by ReeceyBurger123

Is it showing shorted across it diodes will almost neevr fail open ?

First one:
open in one direction, swap probes and some digits appears on the multimeter for a second and then no readings

Second one:
open in one direction, swap probes and 1.096

**jczarniak** · 07-21-2016, 06:10 AM

Re: Samsung PS42-Q97HD, power supply: BN44-00161A clicking ON and OFF

Originally posted by jczarniak

Diodes: KDS181 , according to schematics

Sorry, KDS184

**dick_barton** · 07-21-2016, 06:26 AM

Re: Samsung PS42-Q97HD, power supply: BN44-00161A clicking ON and OFF

Originally posted by jczarniak

First one:
open in one direction, swap probes and some digits appears on the multimeter for a second and then no readings

Second one:
open in one direction, swap probes and 1.096

Is your meter set to diode check or ohms?
Each diode should show something like 0.2 to 0.7 on the meter when set to diode mode and OL when leads reversed. If the diodes are the same type then the readings should match each other.

**jczarniak** · 07-21-2016, 06:32 AM

Re: Samsung PS42-Q97HD, power supply: BN44-00161A clicking ON and OFF

Originally posted by dick_barton

Is your meter set to diode check or ohms?
Each diode should show something like 0.2 to 0.7 on the meter when set to diode mode and OL when leads reversed. If the diodes are the same type then the readings should match each other.

Readings doesn't mach,so I thing at least one must be faulty.

**syaoran123** · 07-21-2016, 06:43 AM

Re: Samsung PS42-Q97HD, power supply: BN44-00161A clicking ON and OFF

Repaired alot of these.

First, test the y-sus board. On connector CN5004 check for shorts between pin 2/3 or 4/5. If theres no short, move on to the power supply.

On the power supply...QX801 and 802 can blow and become open circuit between the legs. In or out of the circuit, what is the reading for each of these transistors between the outside legs. It should be around 10 ohm.

**dick_barton** · 07-21-2016, 06:50 AM

Re: Samsung PS42-Q97HD, power supply: BN44-00161A clicking ON and OFF

KDS181 is a double diode package which you can check with your meter set to diode mode.

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**jczarniak** · 07-21-2016, 06:53 AM

Re: Samsung PS42-Q97HD, power supply: BN44-00161A clicking ON and OFF

Y-sus and everything else disconnected.
I've got 11 Ohm between external legs on the bigger mosfets (QS801 and 802)
10 kOhm between external legs QX801 and 802.
Surface mounted diides DX803, DX804 removed, looks broken, same resistors.

**jczarniak** · 07-21-2016, 06:54 AM

Re: Samsung PS42-Q97HD, power supply: BN44-00161A clicking ON and OFF

Originally posted by syaoran123

Repaired alot of these.

First, test the y-sus board. On connector CN5004 check for shorts between pin 2/3 or 4/5. If theres no short, move on to the power supply.

On the power supply...QX801 and 802 can blow and become open circuit between the legs. In or out of the circuit, what is the reading for each of these transistors between the outside legs. It should be around 10 ohm.

Y-sus and everything else disconnected.
I've got 11 Ohm between external legs on the bigger mosfets (QS801 and 802)
10 kOhm between external legs QX801 and 802.
Surface mounted diides DX803, DX804 removed, looks broken, same resistors.

**syaoran123** · 07-21-2016, 06:57 AM

Re: Samsung PS42-Q97HD, power supply: BN44-00161A clicking ON and OFF

10kohm sounds abnormal. should be low ohms

what number does it say on the resistors RX802 833 832 and 803?

**jczarniak** · 07-21-2016, 07:00 AM

Re: Samsung PS42-Q97HD, power supply: BN44-00161A clicking ON and OFF

Originally posted by syaoran123

10kohm sounds abnormal. should be low ohms

what number does it say on the resistors RX802 833 832 and 803?

Yes, resistors removed are: RX802 833 832 and 803.
Measured outside of the board not showing any resistance.

**syaoran123** · 07-21-2016, 07:03 AM

Re: Samsung PS42-Q97HD, power supply: BN44-00161A clicking ON and OFF

Thats the problem. You have open circuit resistors which may look fine visually.

Different version boards can use different resistor values. I would like to know the number on the resistors?

**jczarniak** · 07-21-2016, 07:11 AM

Re: Samsung PS42-Q97HD, power supply: BN44-00161A clicking ON and OFF

Originally posted by syaoran123

Thats the problem. You have open circuit resistors which may look fine visually.

Different version boards can use different resistor values. I would like to know the number on the resistors?

Cant's read the numbers on the resistors, sorry.
According to schematics they should be 100 Ohm each.

Samsung PS42-Q97HD, power supply: BN44-00161A clicking ON and OFF

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