BUSH-LED22982FHD-No STB-Fluctuating Voltage.

[AlbertRoss]

Hi, have this BUSH 22" TV that has no standby light, no image or sound. Have replaced bad diodes - D9, D25, D12 and D10 using UF5408, all new from same batch. Have 240.00 VDC coming in, fuse ok, 96.0 VDC across both sides of V1 (14N511K) Voltages stable (11.28 VDC) on D25, D12 and D10, voltage fluctuates on D9 - 24 VDC to 28 VDC? Checked caps in circuit with ESR, all seem ok?

Not sure what to check next?

[ReeceyBurger123]

Re: BUSH-LED22982FHD-No STB-Fluctuating Voltage.

Hmm so you still have no standby ? But you have 24v and 12v in out from the diodes ? Sounds like mobo problem to me.

[AlbertRoss]

Re: BUSH-LED22982FHD-No STB-Fluctuating Voltage.

Mobo, would that be the main board?

[stj]

Re: BUSH-LED22982FHD-No STB-Fluctuating Voltage.

check all the voltages first,
i think they are printed under the board.

[AlbertRoss]

Re: BUSH-LED22982FHD-No STB-Fluctuating Voltage.

No numbers underneath any of the boards, I'll check some voltages.

[steviewonder]

Re: BUSH-LED22982FHD-No STB-Fluctuating Voltage.

These power supplies are in a always-on state,So as reecyburger suggests,your mainboard is at fault.

[multimeter]

Re: BUSH-LED22982FHD-No STB-Fluctuating Voltage.

does PS-ON signal fluctuate?,might indicate main board problem,as that signal is generated at the main board,disconnect main board ,voltage still fluctuating on psu?

[AlbertRoss]

Re: BUSH-LED22982FHD-No STB-Fluctuating Voltage.

So unless I can source a main board at a decent price, average on e-bay around £30.00, it's not viable. I presume if I was able to find a board, it would have to be exactly the same, i.e. numbers, screen size, make and model etc?

[ReeceyBurger123]

Re: BUSH-LED22982FHD-No STB-Fluctuating Voltage.

Dam I have a board but its for the 24" version of your set and you cant just replace it with any old 17MB82 you need the EXACT one which matches your panel if not it wont work.

[AlbertRoss]

Re: BUSH-LED22982FHD-No STB-Fluctuating Voltage.

Thanks for looking Reecey, love watching your videos.

Have disconnected the main board and voltages seem to have stabilized?

[vinceroger69]

Re: BUSH-LED22982FHD-No STB-Fluctuating Voltage.

could it be a faulty eeprom? can you get a pre programmed one or a copy of the firmware?

[ReeceyBurger123]

Re: BUSH-LED22982FHD-No STB-Fluctuating Voltage.

Thanks for looking Reecey, love watching your videos.

Have disconnected the main board and voltages seem to have stabilized?

Haha no worries, deffo a mainboard fault. As Vince says my bet is probably firmware but again finding the exact flash is very hard.

[ReeceyBurger123]

Re: BUSH-LED22982FHD-No STB-Fluctuating Voltage.

There is a bloke on here called Michael Dranfeild he has alot of Vestel firmwsre send him a Pm

[AlbertRoss]

Re: BUSH-LED22982FHD-No STB-Fluctuating Voltage.

Will do, thanks.

[vinceroger69]

Re: BUSH-LED22982FHD-No STB-Fluctuating Voltage.

There is a bloke on here called Michael Dranfeild he has alot of Vestel firmwsre send him a Pm

Also worth emailing ohms supplies and see if they have a pre programmed chip the downside is if it does not work its a waste of money, you could i guess wait for a cheap matching mainboard from ebay etc then copy the data to your old board and if works ok sell one board on to get some money back.