Samsung PS-50Q97HD powersupply problem

[flocko]

Re: Samsung PS-50Q97HD powersupply problem

varies with model. solid colours. horizontal and vertical coloured strips, its just a check for PDP faults and Sus board functions

[mjharrisuk]

Re: Samsung PS-50Q97HD powersupply problem

With all connections to plug/sockets reinstated except for the LVDS cable disconnected at the Logic Board, I have fitted a link across 3 & 4 pins on the Logic Board to try and run the test pattern. On applying the AC supply I get no display at all on the screen. When I power down and remove the link to 3 & 4 and reinsert the LVDS cable at the Logic Board and reapply the AC supply I am back to having the display on the screen and the cycling of the relay starting again. Any further thoughts by anyone on what I can test? What are the implications of applying the grounding connection onto the PS on pin connection of CN801 on the Main Power Board to see if it will stop the relay cycling on/off?

[mjharrisuk]

Re: Samsung PS-50Q97HD powersupply problem

I have now found out that the link on the test plug on the Logic Board should be across pins 5 & 6. On trying this with the LVDS cable disconnected from the Main Board the test patterns operate correctly on the screen. The clicking of the relay still occurs after several minutes. So now that the Power Board has been proved to operate satisfactory and solidly without the Main Board connection to CN801 and by grounding the PSon connection does this now signify that the problem lies with the Main Board? Are there any tests that can be done on the Main Board to fully firm up this theory?

[flocko]

Re: Samsung PS-50Q97HD powersupply problem

If you had read my post correctly you would have the main board disconnected from CN801 with PSon grounded, then run logic test if it runs as it should without the relay clicking then the main board is at fault.And as for the implications of grounding PSon with the main board connected, you are back-feeding a (low)0v signal to (high) 2-3v supply signal that is coming from the main board when in standby(not good). the main board switches (low) 0v to PSon when turning on the power board on

[mjharrisuk]

Re: Samsung PS-50Q97HD powersupply problem

Thanks for the clarification flocko. I was reading between two seperate posts that gave differing details for wiring connections confirming the test patterns. I have now aligned the connections for the Logic Board as you describe (except the test pattern links are across 5 and 6) and the test patterns are running continuously with the CN801 Plug removed and a link fitted on the CN801 Socket giving Vson to ground. There is no clicking of the relay on the Power Board. Based on your last post this would confirm the problem lies with the Main Board. Are you aware of anything that can be done to remedy/resolve or further investigate the Main Board problem?

[flocko]

Re: Samsung PS-50Q97HD powersupply problem

Please post board number BN94-xxxxx and photo if you can , you can also disconnect the wire to the PSon pin from the main then replug CN801 but use a ground link to PSon (pin) to fire the power board up that will show any other faults with the main, (the set will run when the AC is applied from wall socket)

[mjharrisuk]

Re: Samsung PS-50Q97HD powersupply problem

Main Board is marked as BN94-01177B. On removal of the PSon connection from the Plug/Socket CN801 and replacing it with a grounding connection the TV comes on but the picture is still cycling on/off with no sound of relay operation on Power Board. Measuring the voltage on the removed PSon cable connection from the Main Board gives the following volts:-
0.686VDC TV is stable in operation. Elevated 3.407VDC for @ 4 seconds picture/TV operation is lost. (Attached image of Main Power Board)

[flocko]

Re: Samsung PS-50Q97HD powersupply problem

A fault is known with this board when they had a heat sink cover fitted , looking at the board you will see a white box screen printed just above the card slot,if you look you will see two 10v 1000uf SMD caps inside the said box (the larger ones ) try replacing these, you can use any 10v 1000uf caps you might have laying around, just make sure to fit them the correct way round. These caps were known to fail on these boards when they had a metal cover over the IC as a heat sink and would give rise to this kind of fault with PSon and sound problems, the heat would build up under the cover and dry out the caps Give it a go worth a shot

[mjharrisuk]

Re: Samsung PS-50Q97HD powersupply problem

Those two capacitors C1110 & C1177 sit on what appears to be a plastic base with solder connections on two sides of the plastic base. Before I do irreperable damage by my ignorance could I just clarify that the removal of these capacitors is by desoldering those connections? or as there are slots between the base of the plastic and the capacitor do they lever directly off the plastic base i.e. plug in. I would rather declare my ignorance than cause damage.

[vinceroger69]

Re: Samsung PS-50Q97HD powersupply problem

these desolder of the board usually pretty easily if not try adding some flux/fresh solder then should come of ok

[mjharrisuk]

Re: Samsung PS-50Q97HD powersupply problem

Thanks! I will take some instruction via Youtube before I have a go. I will need to order up some capacitors as well.

[vinceroger69]

Re: Samsung PS-50Q97HD powersupply problem

for capacitors try cpc as free delivery but its £5.00 minimum order i tend to use panasonic fc fm fr range myself
http://cpc.farnell.com/
or this ebay shop as he sells genuine parts
http://www.ebay.co.uk/itm/Panasonic-...pFYC0lUmNtpYdg

[syaoran123]

Re: Samsung PS-50Q97HD powersupply problem

Would be easier to get some pliers, grip them and twist them gently in each direction. The cylinder and plastic will usually come off leaving the legs behind. You can then finish the job and desolder the legs off using the soldering iron.

[flocko]

Re: Samsung PS-50Q97HD powersupply problem

use a radial capacitor a Panasonic EEUFC1A or the like.there is no need to fit a Alu elec SMD type, just heat the side tabs to remove them with your iron but keep a check on the polarity

[mjharrisuk]

Re: Samsung PS-50Q97HD powersupply problem

I have managed to obtain replacement Panasonic SMD Capacitors of the same values. I have changed out like for like and the problem of clicking is still occuring. I read on another thread that when the Power Board goes faulty it is possible to corrupt EEPROMs on the Main Board. With that in mind I think I will investigate obtaining a replacement Main Board. It would have been interesting to nail down the actual problem, but not having access to all the necessary equipment and firmware make it impossible.

[syaoran123]

Re: Samsung PS-50Q97HD powersupply problem

Faulty eeproms dont cause issues as it warms up. The effect is immediate.

[flocko]

Re: Samsung PS-50Q97HD powersupply problem

It was worth a try , sorry it did not work, make sure to match the BN94-01177 number the code letter is not important when you look for a replacement