Asda Onn 32" LCD TV startup issues

[Jimmy Jangle]

Hi, recently our TV in our bedroom has developed a fault where it stays in standby; any attempts to turn on by remote, or by pressing ch -/+ on the set, makes it come on, but then goes back to standby after 2-5 seconds.

Rather than buying a new TV (as it's only our bedroom one) or paying for a repair, I though I'd come on here, as I'm fairly competent with a soldering iron.

It's an Asda Onn model - I've opened the chassis and lo and behold, it's a Vestel 17PW20.2 (at least that's what I believe as the pics online are virtually the same). Most of the caps look OK, barring one (which I've highlighted, this is actually a pic from elsewhere as I'm in work so can't take pic atm), which is black on top - could this be the cause?

My question is, as I'm going to go in myself to do it, am I better off ordering a new PSU board altogether, or should I order replacement caps?

[tom66]

Re: Asda Onn 32" LCD TV startup issues

You may have a bad electrolytic capacitor, but it is more likely you have the bad poly capacitors on the primary or bad PFC section. Very common. For inexperienced users, I always suggest a simple swap of the 17PW20 and 17PW15 supplies. A 17PW20.2 can usually be replaced with a 17PW15-8 with no issues.

[Jimmy Jangle]

Re: Asda Onn 32" LCD TV startup issues

Fair enough - how easy are we talking for a straight swap?

Does it involve just a simple disconnect/reconnect, screw job?

I'm still half-in/half-out over seeing posts about capacitors zapping you, etc. Will I need to discharge them, and if so, how? I'm probably going to need to invest in some tools, as all I have is a soldering iron (and even that's MIA at the moment as lent to sister-in-law!)

I'll put a pic up later of the PSU to remove any doubt, thanks Tom!

[tom66]

Re: Asda Onn 32" LCD TV startup issues

Simply disconnect & unscrew.
These PSU are generally safe if left for a few minutes to self discharge.

[Jimmy Jangle]

Re: Asda Onn 32" LCD TV startup issues

Finally got round to this. Got a kit off eBay, board turned out to be a 17PW20-1. Replaced C877, C878, IC829, C817, C801, C901, and C892.

But still nothing, just the flashing LED.

Noticed that the caps on C818 and one next to it (same size as C818) have a bulge on top of them, and another at C838 has a black top.

Should I replace these too, as they didn't come in the kit?

[Jimmy Jangle]

Re: Asda Onn 32" LCD TV startup issues

--UPDATE--

Ordered 2 Panasonic 4700 uF 6.3v caps - came yesterday.

Got home from work, removed C818 and C857, replaced with the new caps.

Put back together, plugged in, pressed power button, solid blue led.

Pressed CH+ button, TV came on - Happy as Larry

[tom66]

Re: Asda Onn 32" LCD TV startup issues

Nice one. Glad to hear. Another TV saved from the dump.
As a general rule if I ever see a bad (bulging) cap I'll replace it.

[DaveM62]

Re: Asda Onn 32" LCD TV startup issues

Just a reply to confirm my findings. Sympton: FST won't come out of standby.
5V present. Bottom left of pcb, white multiplug on right, right hand end, red wire. Voltmeter between red wire and chassis. I think this is PL805.
Black multiplug (PL802?) left side. O volts between red wire and chassis. This goes to 24V when the channel button is pressed, but immediately goes back to zero.
(See video on youtube -Matsui MAT32LW507 Power supply repair 17PW20-1)
I replaced 2 bulging capacitors, C818 and C857 (4700uF, anything above 6.3V - I found some 10V caps in my spares box) 24V stays high and set powers up. Well chuffed!

[vinceroger69]

Re: Asda Onn 32" LCD TV startup issues

cool another tv fixed and saved from land fill its a good job there are sites like this badcaps and others like youtube really helps us in doing repairs.