Sony GDM-FW900 not turning on, any idea what the problem is?

[jrodefeld]

Hi everyone,

I have a vintage Sony GDM-FW900 crt monitor that I really enjoy using, but it has developed a problem and won't start up.

This unit was completely serviced a few years ago by Unkle Vito in Los Angeles and it fully passed all tests, was factory calibrated, etc. There was a faulty part (can't remember exactly which one) that was replaced at another repair shop about a year ago. Other than that, it's been working great.

I just say all that to say that this unit is probably in pretty good shape since it's been fully serviced and checked recently.

I'm in a location that doesn't really have any businesses that repair CRTs (that I could find) so I'm wondering if it's something I could potentially do myself?

I suspect something relatively simple.

What happens is that when I push the power button, the unit makes four screeching / clicking sounds, then goes into standby. Nothing shows up on the screen.

There's also a place on one of the boards where there is a flashing blue light that lights up along with the screeching sound.

Here's a video I recorded of the behavior:



Any clue what the problem is?

 

[toast0]

Was disapointed that the blue light was a led, and not a sparking flyback or something. I think your problem is it's broken

Looks like it's smart enough to maybe not totally kill itself when it can't start though, so that's nice.

 

[jrodefeld]

Was disapointed that the blue light was a led, and not a sparking flyback or something. I think your problem is it's broken

Looks like it's smart enough to maybe not totally kill itself when it can't start though, so that's nice.

Any idea what this LED is for? I was hoping it would indicate what the problem is, or help me narrow down the possibilities.

 

[toast0]

Actually, can you read the silk screened part number above that thing that's lighting up? If I'm reading the schematics correctly, that might be marked SG901 ? in which case it's a spark gap, not a blue LED. That's protecting something else from being fried, but I don't have any experience actually fixing broken CRTs...

 

[jbltecnicspro]

Could be a number of things. I honestly don't know. You could get a replacement board from Vito? But you're kinda shooting in the dark here. I don't recall the service manual having any explanation for something like this happening.