VX922 with FSP035-1PI01 PSU

[PlainBill]

Re: VX922 with FSP035-1PI01 PSU

lol, well I was given that nickname years ago when I first started playing with electricity (I was 10 at the time) and blew a few fuses, melted a few wires, sent sparks flying...

The name stuck

Hmm, sounds like something I tried at about that age. The name I got was a lot less pleasant. Good thing it didn't stick.

PlainBill

[masiril85]

Re: VX922 with FSP035-1PI01 PSU

I have this same board with a similiar problem. I replaced a few bad caps and my voltage steady out but the monitor would only flash on and off.

[momaka]

Re: VX922 with FSP035-1PI01 PSU

Might be inverter/backlight issue. Post some pictures of the PSU board if possible. Also, if the original caps were CapXon KF, replace them all, not just a few (except for the big 400v one). Panasonic FM and Chemicon KZE would be good replacements, but Nichicon PW and HE, Chemicon KY, and Panasonic FC might also work.

[spiff59]

Re: VX922 with FSP035-1PI01 PSU

I have a VX710 flat panel with the exact same power supply.
It will power on for approximately a second then go black. The power indicator stays on green and steady, and correctly switches to amber if the input signal is lost.
While on, the screen looks fine, you can repeatedly display the screen for a (short) second by toggling the power, or holding menu button "2".

So, I popped it apart expecting to find barfing caps, but none appear faulty. Although there are a couple of the notorious Capxon's.
Closer inspection showed one (Q6) of the four transistors located on the bottom of the board, beneath the small output transformers for the backlight, is literally blown apart with a nice resulting scorch mark.

Do you think this is a problem?
Kidding!
Ahem... to the real question, were I to track down a replacement for the part (it's marked DKQF), can anyone peer into their crystal ball and give me an idea if I should expect other components of the PS to also require replacement?

Thank you.

[retiredcaps]

Re: VX922 with FSP035-1PI01 PSU

Ahem... to the real question, were I to track down a replacement for the part (it's marked DKQF), can anyone peer into their crystal ball and give me an idea if I should expect other components of the PS to also require replacement?

See

https://www.badcaps.net/forum/showpo...95&postcount=6

PlainBill wrote ...

"Those transistors are Rohm 2SC4672. DK is Rohm's designation for that transistor, Q specifies the high gain range (P would be the low gain parts). I believe the last letter is a lot or date designation. Of course, the part may be available from other manufacturers."

[jetadm123]

Re: VX922 with FSP035-1PI01 PSU

I have a VX710 flat panel with the exact same power supply.
Ahem... to the real question, were I to track down a replacement for the part (it's marked DKQF), can anyone peer into their crystal ball and give me an idea if I should expect other components of the PS to also require replacement?

Thank you.

The DKQF is a 2SC4672 transistor made by Rolm and is available from digikey.com. Review the data sheet to make sure.

Hah hah! Looks like retiredcaps beat me to it! Also, photos of your board would definitely help if you want additional info on parts replacement.

[jetadm123]

Re: VX922 with FSP035-1PI01 PSU

I should also mention that you should probably replace these transistors in pairs, since the hfe of the new part will probably be different from the old one. Also, measure some the other components around the shorted transistor to make sure they're ok. Buy some spares because another failed component may have caused the transistor to short out.

[PlainBill]

Re: VX922 with FSP035-1PI01 PSU

I should also mention that you should probably replace these transistors in pairs, since the hfe of the new part will probably be different from the old one. Also, measure some the other components around the shorted transistor to make sure they're ok. Buy some spares because another failed component may have caused the transistor to short out.

Well said. buy plenty. At $.83 each, they're cheap enough.

I repaired one monitor by replacing the shorted transistors, resoldering the transformers, and replacing a cap that had come unsoldered. It worked perfectly the first time and survived all tests. I currently have another (same circuit, different brand) that has gone through two sets of transistors. Caps have been replaced, transformer passes ring test, transformer leads have been resoldered, etc.

PlainBill

[Redion]

Re: VX922 with FSP035-1PI01 PSU

Hi everyone!

I got another problem with this power supply.

First it wont power on, Replaced the Caps>
Not flashing screen problem, replaced U3, W6, W7 >
Now its turning ON and shows the picture not problem, BUT PSU won't power down the back light when power button is pressed! So now the PSU is always ON!
I separated controller from the PSU and it still stays on, so it is not a logic board.

So far I tried replacing these bit still no luck: Q1, Q2, U1, U320, D9,

Any ideas?

[budm]

Re: VX922 with FSP035-1PI01 PSU

That means the BL_ON control line is stuck high, this control line is fed from the main board, but since the main board is not connected and the backlights still stay on, it means the transistor or IC that receive the BL_ON/OFF line is stuck on and cannot be controlled by the main board any more.
We need to see good clear pictures of both sides of this power supply/inverter board so we can give you the test points o check.

[Redion]

Re: VX922 with FSP035-1PI01 PSU

That means the BL_ON control line is stuck high, this control line is fed from the main board, but since the main board is not connected and the backlights still stay on, it means the transistor or IC that receive the BL_ON/OFF line is stuck on and cannot be controlled by the main board any more.
We need to see good clear pictures of both sides of this power supply/inverter board so we can give you the test points o check.

Please go here : https://www.badcaps.net/forum/showth...432#post278432