Did my monitor just kill my G3??

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Last seen: 4 years 11 months ago
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Did my monitor just kill my G3??

Hi Everyone,First post long time lurker,Long story short i Just got a hold of 4 old Macs + a monitor:- G3 Beige Desktop- Powermac 7200/200 - Mac Quadra 605- MAc LC Apple CRT monitorI booted up the G3 by itself and the light came on and it seemed to boot fine.Booted the monitor by itself. it made the usual suspect noises of a CRT that probably hasn't been turned on in over 20 years but it illuminated and the light turned on.I then booted them together and i saw the post screen + splash screen turn on but then the monitor started buzzing big time and then the G3 powered of and no longer turns on???I then, being a glutton for punishment (+ ignorant) repeated the process with the MAC LC ::facepalm::SAME RESULT Now the Mac LC wont power eitherThis has me bamboozled because i dont see how the monitor could damage the mac's themselves .....So my question to any savvy users is ... did i blow the PSU's on the Mac's or do you think i fried the MOBO's?Or any suggestions like maybe i just tripped something and they will work after they have some alone time?Thanks in advance,Take Care,Dan

Tom Owad's picture
Last seen: 1 day 3 min ago
Joined: Dec 16 2003 - 15:14
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What monitor is this,

What monitor is this, specifically?

freitz's picture
Last seen: 6 months 3 weeks ago
Joined: Jun 11 2013 - 04:37
Posts: 74
I have a Performa 460 that

I have a Performa 460 that uses the same or similar PSU as the LC, I think. The caps in this PSU failed on me from one week to another. I changed them and it has been fine since. The values are a bit uncommon, but the cost for repair was literally cents.

Last seen: 2 years 1 month ago
Joined: Mar 31 2020 - 19:55
Posts: 848
If the same thing occurred on

If the same thing occurred on two different systems, then, as shocking as it sounds, it might be plausible. 


Here is the Apple video pinout:




In theory, if the monitor had some horrible internal short that is feeding VDC into an earth or common pin, it could have shorted through the video circuit. I would expect that circuit to be protected, and that it would not damage the PSU, but without more details it is hard to say. 


You did try the systems on different mains outlets and all of that, right?


Those PSUs may be fused, so, it's entirely possible that you blew a fuse in each with shorts along the video bus, however (again), hard to diagnose without further details or physical inspection on a probe. I suggest checking the power rail for voltages (pinout on the LC is the same as a //gs as I recall), and I believe that the LC will turn on without a keyboard, but my meory is hazy there. 

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