Atari ST video or monitor problem

[developerdude]

I just acquired an Atari STFM with a SM124 and SC124 monitor.

 

When starting it up for the first time, the monitor does power on as well as the computer, it accesses the floppy drive, but the video output is not working.

See attached photo and video.

 

The SM124 monitor has the white line but the SC124 has no video at all.

 

Not sure if it's a monitor problem or an internal video card problem.

 

Any ideas?

 

thanks

 

AtariSM124monitor_problem.mpg

[ParanoidLittleMan]

It can be memory failure, PSU failure ,,, If machine was not used over years later is pretty much likely.

[developerdude]

I assume you mean the PSU in the computer and not the monitor, right?

 

I also tried using the television/rca output to a old TV and also go nothing.

 

I checked the power supply and only one capacity had a swollen top, even though it still powered on.

Should I only replace that capacitor or the whole power supply?

 

thanks

[ParanoidLittleMan]

Of course PSU of computer. Checking with look is not enough, Best that you replace whole PSU, with proven one.

And of course, that does not mean that after it it will work 100% . Repairing electronic is not that simple.

You can do it 'easier' way - with replacing components, sections (it you have good ones), or controlling all suspicious components in some way - with proper instruments for instance.

And there can be multiple errors.

[power]

what happens if you plug the ST into a tele?

[ParanoidLittleMan]

what happens if you plug the ST into a tele?

What happens if someone reads thread carefully ? Maybe that will not ask already answered question. Sorry for my rudeness. I'm known bad guy

[developerdude]

ParanoidLittleMan - Of course that all makes sense. Big Thanks for your help!! I just wish there was some kind of diagnostic tool/method to use since this is such a beautiful machine.

 

Thanks again

[ParanoidLittleMan]

There is diagnostic cartridge. There are voltmeters and oscilloscopes. There are methods too. I worked as service man over 20 years. Then investment pays