dual rectifier

[tom66]

Re: dual rectifier

toshiba regza 42 inch.

As good as saying "My car won't start, it's a blue car, what's the problem..." What is the actual model number on the back panel? My 42" Toshiba I fixed had an entirely different PSU to yours.

[timwebb22]

Re: dual rectifier

toshiba regza 42 inch.

[timwebb22]

Re: dual rectifier

that dark spot must be from the factory. i seen it a few other power supplies online.

[selldoor]

Re: dual rectifier

ok. it looks like im missing the 12-24v for the inverter.

Was the main board connected when testing?
and please can we have a picture of the bottom of the board.

Also can you state the make and model of the TV.

[tom66]

Re: dual rectifier

Can you post a top-down picture of the PSU?

[timwebb22]

Re: dual rectifier

ok. it looks like im missing the 12-24v for the inverter.

[tom66]

Re: dual rectifier

ok i was trying different grounding points while testing. i used the heatsink on the big ic as a grounding point and i see 28v on the 12-24v pin for the inverter and i get 19.6 volts on the pins on the inverter.

You should use the metal case for ground, not the primary side.

[timwebb22]

Re: dual rectifier

ok i was trying different grounding points while testing. i used the heatsink on the big ic as a grounding point and i see 28v on the 12-24v pin for the inverter and i get 19.6 volts on the pins on the inverter.

[timwebb22]

Re: dual rectifier

yeah i have a fluke 75 and a leader 15mhz scope.

these are the voltages
12v- 11.68
6v- 6.4
24v-0
5v-5
power sig 3.28

[tom66]

Re: dual rectifier

i normally repair audio amps and such. im trying tv's now. different ball game now.
i tried google but didnt come up with anything. i did the steps they are good.
i found a bad zener diode over by the big ic now the relay click.

the problem was it was in a pawn shop on display and they left it on all the time until it went out if it helps any.

Yeah, sounds like it just wore out.

Zeners are difficult to test with a meter, but they most commonly fail shorted or open. If you test one way and get a reading around 500mV, it is probably okay. But if you test nearly zero or open both ways then it's failed.

Are you getting any power indication from the TV? Any LED?

Do you have a multimeter?

If so:

- Is the mains fuse OK?
- Does it give a standby voltage (usually 5V)?
- If it turns on does 12/24V come up?

[timwebb22]

Re: dual rectifier

i normally repair audio amps and such. im trying tv's now. different ball game now.
i tried google but didnt come up with anything. i did the steps they are good.
i found a bad zener diode over by the big ic now the relay click.

the problem was it was in a pawn shop on display and they left it on all the time until it went out if it helps any.

[selldoor]

Re: dual rectifier

Common Cathode with Isolated tab, we ran into this problem before with the person did not order the Isolated tab version.

I remember that its here https://www.badcaps.net/forum/showth...987#post237987.

But the datasheet retiredcaps and I have given is for the TO-220F package
which is fully insulated, though it doesnt say so in the sheet other than by the package type.

[budm]

Re: dual rectifier

Common Cathode with Isolated tab, we ran into this problem before with the person did not order the Isolated tab version.

[selldoor]

Re: dual rectifier

Data sheet?

[retiredcaps]

Re: dual rectifier

im looking for the data sheet for this part. part name is en220a it is from a ps to power the inverter.

"en220a rectifier" leads to

[multimeter]

Re: dual rectifier

are they not dual shottky diodes?

set your meter if dmm to 200 ohm,or 10k ohm anologue, pin 1 and 2 should show reading one way ,pins 2 and 3 should show reading one way

[tom66]

Re: dual rectifier

That sounds fine, but to confirm -

Number pins 1-3 left to right.

Labelled (pos/red) (neg/black) respectively (use diode test.)

Test 1-2 should read ~150 - 700.

Test 2-1 should read single "1" or "OL".

Test 2-3 should read single "1" or "OL".

Test 3-2 should read ~150 - 700.

Test 1-3 should read single "1" or "OL".

That looks a lot like a Toshiba PSU.

The power module clamped to the heatsink (the one with lots of pins) can sometimes go faulty, though this usually blows the fuse.

[multimeter]

Re: dual rectifier

the part go right behind the yellow and black transformer. it traces back to the plugs for the inverter. it reads 1.83 in diode check. and 70k in ohms. which seems very low.

are they not dual shottky diodes?

[timwebb22]

Re: dual rectifier

the part go right behind the yellow and black transformer. it traces back to the plugs for the inverter. it reads 1.83 in diode check. and 70k in ohms. which seems very low.

[tom66]

Re: dual rectifier

Do you have a picture of the part, and the area of the PSU it comes from?

If the device is failed (usually shorted), then it may be possible to use an alternative compatible device.