Audio and video problems with Macintosh Plus

[Dipper184]

Today I powered on my Mac Plus and I heard really weak start up beep and there was this weird pattern on screen for a few seconds, then the missing disk screen showed up and it booted into a system as usual, except there was no sound. Second time I powered on the Mac there was no sound (not even quiet beep), also there wasn't any audio output from the audio jack on the back.

 

[bibilit]

Troubleshoot ram and voltage outputs first.

 

[Dipper184]

Troubleshoot ram and voltage outputs first.

I don't know how to do it, also I don't have the equipment... 

 

[bibilit]

Checking Ram is easy, but you need another set to swap aound.

A cheap Multimeter is all you need to check voltages.

https://www.classic-computers.org.nz/blog/2015-05-14-mac-plus-checkerboard.htm

 

[Dipper184]

Checking Ram is easy, but you need another set to swap aound.

A cheap Multimeter is all you need to check voltages.

https://www.classic-computers.org.nz/blog/2015-05-14-mac-plus-checkerboard.htm

I know this reply is late because I didn't the have time to do this. I skipped the RAM and voltage test and checked  the solder joints on J4 and some were cracked. I re-soldered them, it didn't help, but upon seeing the checkerboard I heard screech, second time I powered on the mac there was no sound.