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Sony KDL-22BX200 - no inverter

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ocf:
Any idea if the computer CCFL inverter will be powerful enough to test the lamps in the tv? CFL tubes that are usually connected to this inverter are 12" coloured ones. Input to inverter is 12v

ocf:
Update and some progress finally!

I received a generic LCD inverter model number AVT4029, I have included an image below, it takes 10-30v DC input and powers 4 lamps up to 22"



I decided to test this on a Bush tv that has an backlight issue, the input for the original inverter in the TV is identical to the above generic one. Both use a 6 pin connector, 2 pins each for ground and 12v and one pin each for Von/off and brightness adjustment.

The generic inverter powered the Lamps perfectly and the TV looks good!

Next step was to test the Sony with the inverter, unfortunately it does not have a 6 pin output as the bush did, in this case the inverter is combined on to the main power PCB.

I jury rigged the inverter to use the 6pin power from the bush tv and connected the lamps from the Sony. THEY ALL WORK!! The Sony turns on and picture is clear as day with the generic inverter so no lamp issue there.

Problem must be with the power circuitry of the inverter on the mainboard I am still only seeing 6v on the primary coils of the inverter this clearly should be 12v. I replaced the only capacitor that was on the inverter side of the power board but this made no difference. What could be making that 12v signal drop by half? When I put my multimeter probes on the primary side I see an initial 6v when the TV starts but this steadily drops and does not rise again as if a cap is is discharging.

The V on/off pin on the inverter connector that tells the inverter to turn on and off, does anyone know how this is triggered? I am thinking to jury rig the generic inverter inside the TV and hook it up to a 12V source on the power PCB but the inverter wont turn on unless it sees that V ON signal.

Any advice welcome guys!

Turnip:
Hi ocf,

Had the issue maybe twice, both times transformer with shorted turns. My first one had a bulgy supply cap C2006(1000/16) so replaced it and noted the inverter supply voltage was 14v rather than your 6v and with a duff transformer.

Was initially confused as checked tranny secondary windings with an Avo and couldn't notice any difference - With a digital meter it was obvious - Chris.

ocf:
Are you referring to the inverter transformer or the transformer that takes the AC input from wall and makes the DC for all the boards?

I have already replaced the inverter transformer and this has made no difference, also replaced all caps except 2 680uf ones that I didn't replacements for. C2006 has been replaced

ocf:
I can get the generic inverter to power the sony's lamps if I give it 5v on the V on/off pin. I tested it with an external 12v and 5v transformer. If I could internalise this generic inverter and find a place to draw 12 and 5v on the mainboard then this could work.

I have found a 12v and 5v source but they are still live when power is off and the inverter needs to power down when the TV is turned off.

Any suggestions?

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