samsung ps42q97hd clicking

[xmandarkx]

just picked up this tv and was told it just clicks and nothing else but was given a replacement board with it. i opened it up and he has mangled the power board, broken tracks and under rated caps been used to replace the blown ones. the other board looks ok other than 3 blown caps.

when you plug it in it starts to buzz and just get relay click. theres a blue/white light that comes on on the front but that is it.

vs voltage starts at 0 and rises to 7.4v
va voltage is 63v
any help where to start would be great, thanks

[freakaftr8]

Re: samsung ps42q97hd clicking

First get rid of that power board .If it's mangled beyond all recognition it's not worth trying to repair

[xmandarkx]

Re: samsung ps42q97hd clicking

sorry i should have said that board is out and wont go near a tv again, the one i was supplied looks ok other than the caps and thats the one that clicks. the mangled one did nothind at all when i plugged it inm

[selldoor]

Re: samsung ps42q97hd clicking

Replace the caps? along with any of the same make/series except for the BIG
cap.

[xmandarkx]

Re: samsung ps42q97hd clicking

just replaced 2 but last one i dont have the correct uf rating for, thats the next step. i took the caps off the other board (the new ones he tried to solder in but failed) anything else i can test while i source another cap. the one i need is 35v 1500uf dont suppose there common in any other electronics? i got a shed full of crap that might have one in.

[selldoor]

Re: samsung ps42q97hd clicking

You should be using good quality low esr caps panasonic FR FM or FC or Rubycon Nichicon equivalents.

You could use 1800 or 2000uf 35v if they will fit in the space

[tom66]

Re: samsung ps42q97hd clicking

Really not a good idea to borrow caps for many reasons (voltage forming, dried lytics, etc), CPC have free delivery on any order right now, put some Panasonics in it!!

Also have you tried isolating X- and Y-main? Standard stuff as discussed in many other threads.

[xmandarkx]

Re: samsung ps42q97hd clicking

i have used samwha caps. can i get it working with any cap with the correct rating then replace when i know it works?

[xmandarkx]

Re: samsung ps42q97hd clicking

yes i have tried powering on with every board isolated at some point but makes no difference.

[tom66]

Re: samsung ps42q97hd clicking

No, because you cannot be sure that capacitor will work properly unless you have a complete capacitor analyser (ESR, leakage vs voltage, capacitance), and even then it's hardly worth the risk of causing problems, soldering old caps in and pulling them back out... how much is your time worth to save a few quid on capacitors?

Check if PSU VS, VA are good with and without X-main/Y-main board

[xmandarkx]

Re: samsung ps42q97hd clicking

right i will get some ordered tonight. i will test the voltages now.

[xmandarkx]

Re: samsung ps42q97hd clicking

both connected vs 7v
x connected vs 7v
y connected vs 7v
both disconnected vs only gets to 3v then slowly drops.
va is constant 63v

[tom66]

Re: samsung ps42q97hd clicking

Try adjusting VS control, any change? Check for cold solder joints on power board.

[xmandarkx]

Re: samsung ps42q97hd clicking

no change adjusting vs. it clicks then the voltage builds then clicks and drops a but then click and rise then click and drop till it hits 7v
i resoldered the mosfets last night.
from testing it seems like the fault is in the vs corner of the board as all other voltages check out.
i will take the board off and look for bad joints.

[freakaftr8]

Re: samsung ps42q97hd clicking

I usually on this case look at shorted diodes and opto isolators.