Dead BN44-00458B

[speedypro]

Normally if few caps are faulty, I normally see the standby light, in most case.

This board is dead. No standby light. Fuses, caps and diodes are ok. AV board bad?

[ReeceyBurger123]

Re: Dead BN44-00458B

Why has the photo got things in Red ? You diagnosed it ? Checked voltages ?

[budm]

Re: Dead BN44-00458B

Is that your board? Any good clear straight shot picture of the bottom side of the board?
DCV between the two legs of the main filter cap?

[speedypro]

Re: Dead BN44-00458B

Sorry, guys. I've left work. Red circles are what I've replaced with new and still dead. I'll do those tests tomorrow.

[ReeceyBurger123]

Re: Dead BN44-00458B

Why did you replace them though ? Did the original diodes test bad ?

[speedypro]

Re: Dead BN44-00458B

Why did you replace them though ? Did the original diodes test bad ?

I thought they were short. But it turns out they are short when in circuit.

[ReeceyBurger123]

Re: Dead BN44-00458B

I thought they were short. But it turns out they are short when in circuit.

Ahh I see

[budm]

Re: Dead BN44-00458B

BTW, so you do not have A5V at pin 14 of the connector CNM803 when you do not have other boards connected to it?

[speedypro]

Re: Dead BN44-00458B

Is that your board? Any good clear straight shot picture of the bottom side of the board?
DCV between the two legs of the main filter cap?

No voltage on pins of caps where the red circle is on picture above.

Image of reverse:

[speedypro]

Re: Dead BN44-00458B

BTW, so you do not have A5V at pin 14 of the connector CNM803 when you do not have other boards connected to it?

No voltage on the 450v cap's pins.

[budm]

Re: Dead BN44-00458B

Do you have 240AC between the two inner pins of the bridge rectifier?
If you do, then what DCV you have on the two outer pins of the bridge rectifier?
I would also resolder the pins of the transformers, the bridge rectifier, the legs of the devices mounted on the heatsinks.

[speedypro]

Re: Dead BN44-00458B

Do you have 240AC between the two inner pins of the bridge rectifier?
If you do, then what DCV you have on the two outer pins of the bridge rectifier?
I would also resolder the pins of the transformers, the bridge rectifier, the legs of the devices mounted on the heatsinks.

Red: 338DCV
Yellow: 247ACV

Seems ok on the bridge rectifier. I have not seen any colder solder points. But can resolder. Anything else to check as 0v is going to the AV board?

[budm]

Re: Dead BN44-00458B

OK, now we have established that we do have main DC to run the SMPS, now we need to get the standby power supply up and running first.
ICS801S is the standby SMPS IC, we need to get the P/N to get the pin out to find out if we have VCC and the 338VDC to feed the standby transformer TS801S or not.

[speedypro]

Re: Dead BN44-00458B

OK, now we have established that we do have main DC to run the SMPS, now we need to get the standby power supply up and running first.
ICS801S is the standby SMPS IC, we need to get the P/N to get the pin out to find out if we have VCC and the 338VDC to feed the standby transformer TS801S or not.

Thanks. I'll investigate from here then let you know.

[vinceroger69]

Re: Dead BN44-00458B

might be worth checking all these parts in the repair kit for this board
http://www.ohmsupplies.co.uk/REPAIR-...01-FAULTY-DEAD

[speedypro]

Re: Dead BN44-00458B

Ok. Bought a used "working" board off eBay. Standby light comes on. Pressed to turn on, red light blinks then goes back solid red. Bad board or main board?

[dick_barton]

Re: Dead BN44-00458B

What voltages do you have or not have on connectors CNM803 and CNL802