LC475 no video output, suddenly

[Plasticoat]

Hi,

yesterday my 475 froze midway through boot process, since then, I’m unable to get any video output.

the bong is strong at startup, however the

converter to vga does not process a signal

to turn on my monitor.

the battery is fine, however I’m stumped,

any ideas please, thanks in advance

 

[MrFahrenheit]

Has it been recapped ?

 

[Challenger 1983]

If you have already recapped the machine try cleaning the board again as sometimes cap goo can get underneath chips and components 

 

[Plasticoat]

Thanks for the advice, I’ll clean the board again, I’ll keep you posted.

 

[Plasticoat]

Hi again, this LC is fighting all the way !

i cannot reset the pram now, and I’m wondering if it’s become corrupted?

is there any tricks to resetting, the keyboard just is not working. Command option and p, r

on restart, no reply from board.

so I’m left with a 475 that does nothing other than bong.

thanks again

 

[MrFahrenheit]

The 475 should have a red on board button to reset in case of corruption. 
 

Unplugged, with no battery installed, press and hold down button for 10 full seconds. Wait a minute. Install battery. Wait a minute. Power up. 

 

[register]

Is the VRAM properly seated? It is possible to start a LC 475 with no VRAM installed, resulting in black 1-pixel graphics output. You get a black pixel in a screenshot that was created in such a setup. One possible use is a headless machine that is used as a print server or file server, resulting in a minimum of graphics processing.