Severly distorded LCD display

[WTP Pepper]

Hi
I have a Logitech SB radio with a colour LCD display (not 16x2 but graphical).

On switch on it displays characters slightly blurred then after about 2 mins, it goes completely white.
The radio still works underneath but I cannot read anything on the LCD.

Does anyone know what the likely mode of failure is that is fixable? Logitech have no idea and want to sell me another. It's only two years old. It was expensive and out of warranty but still seems a shame to throw it away.

I have opened it and there is nothing obvious. All connectors seat correctly.

TIA

 

[ericgibbs]

hi,
One possible failure cause could be the LCD's Back Plane oscillator, typically around 100Hz.

This BP osc is usually an integral part of the controller.

One point to check is that the LCD, if in a socket, is firmly seated in the connector.

 

[Nigel Goodwin]

Most likely it's a poor connection to the actual LCD 'glass', these are either 'bonded' or made via some type of conductive rubber, neither seem very reliable.

 

[Mr RB]

All characters slightly blurred, then all character completey gone, might be symptoms of a focus voltage fault.

Some LCDs need a -ve focus or bias voltage that comes from a tiny inverter circuit. Replacing caps in that circuit might fix it, if it is that type of display.

 

[WTP Pepper]

All characters slightly blurred, then all character completey gone, might be symptoms of a focus voltage fault.

Some LCDs need a -ve focus or bias voltage that comes from a tiny inverter circuit. Replacing caps in that circuit might fix it, if it is that type of display.

Will give this a go and report back. Thanks.