PS51D550C1KXXU, Samsung X-SUS rebuild

[zen]

Not expecting a schematic but would be helpful if available.

PCB PART NO - LJ92-01763A

PBA REVISION - AA4

This board drives a full HD display.

[zen]

Re: PS51D550C1KXXU, Samsung X-SUS rebuild

First of many casualties, I'm sure.

Q4101 & Q4104, BOTH TYPE 30G124

D4103, TYPE SF10400H, replace as a precaution.

[zen]

Re: PS51D550C1KXXU, Samsung X-SUS rebuild

Q4301 & Q4302, BOTH TYPE RJP30H1, S/C

D4302, TYPE SF10A400H, replaced as a precaution.

[zen]

Re: PS51D550C1KXXU, Samsung X-SUS rebuild

Q4202 & Q4503 (30G124) also faulty

[zen]

Re: PS51D550C1KXXU, Samsung X-SUS rebuild

Replaced all the associated GATE drive chips for the blown FETS.

U4301, U4201, U4411, U4412.All type FAN73711

[zen]

Re: PS51D550C1KXXU, Samsung X-SUS rebuild

R4301, 15R

Measured correct, although looked like it had cooked.

[zen]

Re: PS51D550C1KXXU, Samsung X-SUS rebuild

After attending to many poor solder joints on X-SUS, Y-SUS & PSU, plus replacing thermal pads that had leaked out, I gradually applied power to TV using the variac.

Set now starts up, with VS & VA supplies spot on.

The VE according to screen label is high though, at 100V instead of 80V.

Adjustment on X-SUS has absolutely no effect.

Any ideas?

[zen]

Re: PS51D550C1KXXU, Samsung X-SUS rebuild

Been working ok for days.

Heatsinks on X-SUS, no warmer that Y-SUS.

Kicking it out like this.

Also noticed some sparkles at top end of display, especially on white screen.

Guessed weakness of display over time, therefore increase VS volts by 3V which cleared sparkles.

[nomoresonys]

Re: PS51D550C1KXXU, Samsung X-SUS rebuild

that looked like an excellent job to me, you were careful and methodical and didn't rush it and blow anything up or have to redo anything.

[zen]

Re: PS51D550C1KXXU, Samsung X-SUS rebuild

Very kind of you to mention, thanks.