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Grundig GU15WDT inverter bodge needed
ProDave:
15" freeview LCD tv.
Inverter shuts down after about 5 to 10 minutes. I suspect aged backlight tubes out of spec.
So I need to disable, or modify the inverter's shutdown parameters.
It's an all in one PSU / inverter board:
Proview Technology Inc
PI-XXXXTLTX VERSION:A
200-001-XXXXTLTX-AH
DTAE:2007/08/10
The main chip is a TL494C
Anyone know how to make it a bit more forgiving of aged ccfl tubes?
watteau:
Hi,
Here's a list of overides I have, can't remember where I got them from.
Inverter Protection Circuit Over-Ride.
By AMIT
For Test Purposes ONLY!!!!!!
A few tips to cancel protection :
IC TYPE: CONNECTION:
BIT3105 CONNECT 5.6V ZENER TO PIN 2
OZ9925 CONNECT GROUND TO PIN 12
494 2.4V ZENER TO PIN 3
BD9983 2.4V ZENER TO PIN8
0Z960 LED TO PIN10
Regards,
John
Turnip:
Hi Pro-Dave and thanks John,
Had similar prob, and duff tubes quickly get worse - change them if tube checker cuts out. Think PS/Inverter is a Vestel IPS (under that Proview label) but such problems point to backlight CCFL, esp with an initial pink piccy - Chris.
ProDave:
I did come up with a fix bodge.
I sumised it might be over voltage, so I fitted an extra load in the form of a 4.7 megohm resister across each inverter output.
That initially worked and the set ran for a whole evening.
But soon the problem was back.
Yes the tubes do start up with a distinct pink hue, and I opened up the panel and had a look and the ends of the tubes are severely black.
So yes the correct repair is new tubes, but frankly on this particular set it's not worth it.
So it's one to be dismantled, the main board and PSU / inverter to be sold on ebay and the screen kept just in case I get another one with a smashed screen (but good tubes) in the future.
sparky:
hi
i have a gu16wb2 no dtv had any probs or how to get into
service menu seems to work ok thro scart
thanks dave
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