Samsung HPS5053 Relay Clicking

[midnightg35x]

I have an older Samsung HPS5053 with a continual relay click on power up. It does have a unique symptom though. I have gone through the service manual and the troubleshooting chart says replace the main board because I can remove all of the external cables and short pins 4 and 5 of the CN804-2 test connector with the relays no longer clicking. I am not convinced this is quite the reason though.

If I remove all of the external cables to the power supply, I can jump the PS-ON line to ground and the power supply will turn on with all correct voltages. However, judging by the pitch of the sound coming from the power supply, it is taking 3-4 seconds to stabilize. The next interesting point is that if I let the power supply stabilize, remove PS-ON, and then immediately reconnect all of the external cables, the TV will power on and act normal. If I keep everything hooked up this way and have the TV powered off for more than 5 minutes, it will go back to the constant relay clicking. So to me, it seems like something on the power supply is taking too long to power up and it causes an endless power cycling loop. It will do this loop if the main board is connected (the high voltage inverters don't make a difference either way). This would point to the switched D5.3V line or switched D12V line. The biggest rub here is that somebody else has tried repairing this power supply already. A bunch of the larger caps that fit, but are not stock are installed in certain places. My current theory is that these caps are too large (in capacitance) and when the power supply turns on it takes too long to charge the caps up before the internal fault timeout occurs. Meaning, the voltage rail takes too long to come up and the power supply shuts down and resets. What I need to know is what the original capacitors were so I can replace them with the same values. I cannot find the schematics for the power supply alone. The service manual does not have the power supply schematics and every picture I can find is just a top down view so I cannot see the values. I can tell that they are different caps than standard pictures though.

ShopJimmy picture of the board

Power Supply: PSPF501A01A (Samsung Part BN96-03735A)
Caps I think are non-stock: CM859, CM861, CM870 (UCC LXY 2200uF, 35V). CM866 (Nichicon UPW 470uF 35V). CM874, CM871, (UCC KMG 2200uF 25V that look to be transplants from CM859 and CM861).

Anybody have experience with this?

[R_J]

Re: Samsung HPS5053 Relay Clicking

It's more likely that one of small electolytics are bad, 4.7 - 100µf 25v - 50v These small caps are usually overlooked, and are usually in feedback or start circuits.

[midnightg35x]

Re: Samsung HPS5053 Relay Clicking

It's more likely that one of small electolytics are bad, 4.7 - 100µf 25v - 50v These small caps are usually overlooked, and are usually in feedback or start circuits.

I thought about that and checked the ones on the "cold" side of the transformer and they all looked fine when I pulled them out. I did not check ESR, but I did check capacitance.

[R_J]

Re: Samsung HPS5053 Relay Clicking

I'm talking about the ones on the primary side, Also check your PFC voltage (the voltage across the main caps) in standby it is usually around 160v but should rise to 380+ volts whith the power on command, Can be checked on F803 using hot ground [anode side of DB851] This diode is next to relay RL8025
Also check the supply voltage for the relay circuit, if it drops, the relay will not stay on either.

[midnightg35x]

Re: Samsung HPS5053 Relay Clicking

I'm talking about the ones on the primary side, Also check your PFC voltage (the voltage across the main caps) in standby it is usually around 160v but should rise to 380+ volts whith the power on command, Can be checked on F803 using hot ground [anode side of DB851] This diode is next to relay RL8025
Also check the supply voltage for the relay circuit, if it drops, the relay will not stay on either.

I ended up checking all polarized caps on the board. I did find one bad 47uF 50V cap (it measured 30uF) that was under that big metal shield in my pictures. I do not know if that was causing my issues or not. I did also replace CM871 and CM874 with 470uF 50V caps. These were the ones that looked like transplants to me compared to the shopjimmy pictures. The shopjimmy pictures in those locations look like the green 470uF 50V other places in the board, but I cannot tell exactly because there are 2 different green label caps. This is the reason I was hoping someone could confirm what capacitance those are supposed to be. It looks like using too large triggers a shutdown, but I do not want to go too small either.

With this configuration, the TV does turn on and appears to operate normally now. I will change out those two caps to the correct cap though if I can find out what the originals were.