Foehm & Hirsch FH-37LMH 37" lcd no picture sound or backlight

[homerclone]

Hi
Need your valuable help again.
I have this tv it powers on and then goes into stand by mode (no picture sound or backlight).I have done a bit of trouble shooting.
1. all voltages ok coming from power board (no bad caps)
2. I can get the backlight to work if I disconnect the on/off and adj plug from the main board to the inverter.( with this disconnected screen will light up but will shut down again into stand by mode)
3. With this lead disconnected I get 0 volts on main board from the pin on/off and adj pin. And with this still un plugged if I test the on/off and adj pin on inverter in getting 2.5v on adj and 3.8v on on/off
Do you think main board or inverter board ?
Thanks for your help
Mark
ps can post pics if this helps

[homerclone]

Re: Foehm & Hirsch FH-37LMH 37" lcd no picture sound or backlight

Hope this picture helps explain it for me.

[homerclone]

Re: Foehm & Hirsch FH-37LMH 37" lcd no picture sound or backlight

Anyone shed any light please?

[selldoor]

Re: Foehm & Hirsch FH-37LMH 37" lcd no picture sound or backlight

Have you got a known signal/source going in - dvd is good.
You may have to toggle through the sources to pick it up.
when the panel is on can you see any menus of any description.
Are you using a remote to switch on and off.

EDIT
Can you monitor the on/off pin on the inverter board while the screen is going form off to on and back to off

[homerclone]

Re: Foehm & Hirsch FH-37LMH 37" lcd no picture sound or backlight

Have you got a known signal/source going in - dvd is good.
You may have to toggle through the sources to pick it up.
when the panel is on can you see any menus of any description.
Are you using a remote to switch on and off.

EDIT
Can you monitor the on/off pin on the inverter board while the screen is going form off to on and back to off

Hi Selldoor
Thanks a lot for your reply. I cant get any picture or sound or menu etc have tried your idea of connecting dvd player and changing source but still no joy have connected xbox as well with no joy.
I have monitored the on/off pin and the adj pin.
in stand by the on/off pin has 0 volts off stand by 0 volts back to stand by 0 volts.
in stand by the adj pin has 0 volts off stanb by 0 volts back to stand by 5 volts but quickly drops to 0 volts.
Looks like main board not giving inverter signal to turn on
Im thinking main board what do you think?
Thanks
Mark

[selldoor]

Re: Foehm & Hirsch FH-37LMH 37" lcd no picture sound or backlight

I know very little about tvs - it does look like main board is the problem but others may suggest more tests. Could even be both as even when the lights come on they shut off again which could be inverter or the bulbs.
Perhaps try it all together but with the cable from the mainboard unplugged in case there is a problem on the tcon causing the main to shut down.
perhaps post pictures - one showing the whole set with the back off and one of each board. Someone may spot something.

[homerclone]

Re: Foehm & Hirsch FH-37LMH 37" lcd no picture sound or backlight

Hi tried connecting it all back together then disconnecting cable from main to t-con board but still get the same result

Also attached are pics of back of tv and pics of the boards

Hope it will help

[homerclone]

Re: Foehm & Hirsch FH-37LMH 37" lcd no picture sound or backlight

more pics

[homerclone]

Re: Foehm & Hirsch FH-37LMH 37" lcd no picture sound or backlight

Last pic :-)

[selldoor]

Re: Foehm & Hirsch FH-37LMH 37" lcd no picture sound or backlight

Another test is to unplug all the bulbs except one and power up - see if it flashes then unplug that and plug in bulb 2 and see if that flashes and so on. They will never stay on but it may show up a totally broken bulb it will not flash at all or may flash dimmer than the others.

[homerclone]

Re: Foehm & Hirsch FH-37LMH 37" lcd no picture sound or backlight

Hi
Just an update and a request for some help ref this post.
I could only purchase a main av board from a 42" set and have fitted it.
The good news is the tv now displays a picture. However the colour images are bad see pic.
I think it has something to do with the firmware as its a board from a 42" and not the 37". I cant get into service menu (as I don't know how).
Could I remove the chip that stores the firmware from the 37" board and attach it to the 42"?
If so what chip holds this info (attached is picture of board).
Has anyone tried this before?
Thanks for your help
Mark

[selldoor]

Re: Foehm & Hirsch FH-37LMH 37" lcd no picture sound or backlight

could be the 2 atml chips top right in your pic but not certain

[budm]

Re: Foehm & Hirsch FH-37LMH 37" lcd no picture sound or backlight

That is solarized picture which is due to bad GAMMA Voltages on the T-CON board, was it like that before the TV went out? U500 on the T-CON is the GAMMA Vref IC.