17PW20.1 blows fuse right away

[dick_barton]

Re: 17PW20.1 blows fuse right away

So are you saying the reading from the fuse to hot ground of the capacitor was 0.733K ohms = 733 ohms. You need to check the bridge rectifier. Plenty of youtube video's online to show how.

[wylcot]

Re: 17PW20.1 blows fuse right away

I'm sorry but....
I can't find any BR.
I'm used to what they look like on pinball machines, but even on the manual, i can't spot a BR....

[diif]

Re: 17PW20.1 blows fuse right away

It's black and rectangular with a sloping corner. Just down from the power connector to the left of one of the two big coils.

[wylcot]

Re: 17PW20.1 blows fuse right away

Oh, Ok !
Thanks Diif !
So it's D800, then... a GBU4M...
That's the one i was eyeing on, as it has 4 pins.

Ok. I'll try to check it...

[wylcot]

Re: 17PW20.1 blows fuse right away

Alright.
So I tested the BR according to techniques seen on Youtube...

So, between + and AC, I get 532
Between + and 2nd AC, I get 540

But then... between + and -, I should get the double, right?
And I only get 522.

Does that mean it's faulty?

Do you think I should unsolder it from the board to be sure to check it correctly ?

[dick_barton]

Re: 17PW20.1 blows fuse right away

Test as if single diodes
AC1 to DC+
AC1 to DC -
AC2 to DC+
AC2 to DC-

[wylcot]

Re: 17PW20.1 blows fuse right away

Well then I get between 420 and 460...
four times.

[dick_barton]

Re: 17PW20.1 blows fuse right away

That sounds OK
Can you measure the resistance from D824 to negative leg of that large capacitor (post #8) for each side of that diode. You will need to wait a few minutes after powering off the set to let the voltage on that capacito drain away.

[budm]

Re: 17PW20.1 blows fuse right away

What resistance reading do you get when you measure between the two legs of the main filter cap in both directions? The meter should show low resistance first the the resistance should rise as the cap charged up.
https://www.badcaps.net/forum/attach...4&d=1607373901
Btw, you did check the PFC MOSFET and the PFC Diode mounted on the heatsink right next to the main filter cap, correct?

[wylcot]

Re: 17PW20.1 blows fuse right away

Well it seems fine.

I'm giving up on this one.
It'll go for spare parts.

Thanks for the help, guys ! I learnt a lot !