Goodmans GTVL37W24HD LCD TV

[budm]

Re: Goodmans GTVL37W24HD LCD TV

"DMM com lead to chassis ground."
When you work in the primary side (Hot/Line side) you do not use chassis as the primary circuit ground ref, you have to use the Negative leg of the that large 450VDC main filter cap as the circuit ground ref.
Chassis is the circuit ground ref for the secondary side (Cold side) of the circuit.

[notallbad]

Re: Goodmans GTVL37W24HD LCD TV

All pins on IC1001 - MC33262 are reading around 100v D.C.

Also when taking the reading I think its a transformer buzzing/humming, when the probe is making contact with the IC pin, stops buzzing when removed.

[notallbad]

Re: Goodmans GTVL37W24HD LCD TV

Measurements taken as per Test Points on PS schematics:
TP1001 - 243v a.c
TP1002 - 261v a.c
TP1003 - 715v a.c
TP1004 - 104v d.c
TP1005 - 100v d.c
TP1006 - 5v d.c
TP1007 - 23.7v d.c
TP1008 - 22.5v d.c

TP1001 - 3 ground main filter cap neg leg
TP1004 - 8 chassis ground

[notallbad]

Re: Goodmans GTVL37W24HD LCD TV

After reading Budm's guide I connected 2 x 12v car bulbs, 5w bulbs in this case as thats all I had spare, in series to the 24v rail outputs from the PS.
I am receiving the same results as if the inverters are still connected, the voltage rises gradually up to 22.5v roughly, causing the bulbs to strobe until full scale voltage is available.

Does this mean that there is a regulation problem? I still have a gut feeling its a cap issue but then I'm not that knowledgeable in this area.

[tom66]

Re: Goodmans GTVL37W24HD LCD TV

If you still had the inverters connected then the PSU may have been overloaded hence the pulsating output.
Your problem is not on the PSU because the backlight and main board are both working OK apart from being in test mode.

[notallbad]

Re: Goodmans GTVL37W24HD LCD TV

The bulb test was done with the inverters disconnected from the PIM, I think its called, its not the PS but this is what the PS connects to and what connects to the main board and the inverters.
The inverters 24v supply was disconnected from the PS, eliminating the PIM and the bulbs were still strobing.

I don't understand how you can say its not the PS, afterall the Main A/V board just provides a 3v signal which kick starts the PS 24v rail into action, I guess if I were to provide an external 3v supply to the PS for the BL_On signal it would eliminate the main A/V board, PIM and inverters.

[davie248]

Re: Goodmans GTVL37W24HD LCD TV

For anyone still looking for a solution to this. I had a Teknika set with the same problem managed to get TV working normally by pressing "menu" "input select" and "power" button simultaneously.
When switched back on, TV was fine.

[notallbad]

Re: Goodmans GTVL37W24HD LCD TV

Thanks, shall let you know if that works.

Though is that with the front/side panel buttons or the remote? Press and hold whilst powering up or hold, release then power up?
Shall have to try a combination.

[notallbad]

Re: Goodmans GTVL37W24HD LCD TV

Erm, no joy with that unfortunately.

[notallbad]

Re: Goodmans GTVL37W24HD LCD TV

I have obtained a Bush tv with a smashed screen, still turns on and shows a display, menu etc... and found the same eeprom on the a/v board, Atmel 24c64, so shall have a go at swapping it over.

What do you guys think?

I have read to flood all 4 pins on one side with solder then re-heat to lift that side of the eeprom, then the same to the other.
I have practiced this successfully on an old board with a couple of unknown 8 pin I.C's.

Is there any issues with heat on the I.C causing damage?

[tom66]

Re: Goodmans GTVL37W24HD LCD TV

No, that won't work... An EEPROM is a device which has a custom program on it (storing things like user settings.) It'll probably refuse to boot. Some TVs will boot with a blank EEPROM though, so try that.

[notallbad]

Re: Goodmans GTVL37W24HD LCD TV

Well, I have nothing to lose and it needs removing from the board anyway, so may just try it and if it doesn't work I shall order a couple of blank eeproms.

So powering up without an eeprom will have the same effect as powering up with an incorrectly programmed eeprom.

[notallbad]

Re: Goodmans GTVL37W24HD LCD TV

Anyone know how to enter Service Mode on this TV?
Need to reset to defaults.

[tom66]

Re: Goodmans GTVL37W24HD LCD TV

Powering on without an eeprom probably won't work at all.

[notallbad]

Re: Goodmans GTVL37W24HD LCD TV

Well I decided to just go ahead and swap it over, on power up it started fine but I need to enter service mode now to change settings, first trying to reset to default.
There are a couple of peculiar things happening perhaps due to the eeprom not having all the correct data needed.
It is a good sign as the tv does actually come on now and I have had an AV source and hdmi connected and get a good picture, menu osd shows too!

[tom66]

Re: Goodmans GTVL37W24HD LCD TV

I guess by chance that EEPROM does not have the "test mode" bit set, but probably every other setting is completely wrong!

[notallbad]

Re: Goodmans GTVL37W24HD LCD TV

Could be thats why I'm hoping to find the Service Mode to reset.

[notallbad]

Re: Goodmans GTVL37W24HD LCD TV

Tried Menu 4 7 2 5

Does not work, arghhhh!

[tom66]

Re: Goodmans GTVL37W24HD LCD TV

... it's not a Vestel is it?

[notallbad]

Re: Goodmans GTVL37W24HD LCD TV

not sure