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5150 5160 power supply swap.

NoSmoke

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Mar 30, 2020
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Minnesota USA
I am new today and just want to say thank you for this forum and to those who share their knowledge.

That said, I have a 5150 that turns on but does nothing past that. I have a 5160 that is fully functional. Question: will the 5160 power supply work in the 5150 without hurting anything? I just want to do this for testing purposes incase the 5150 power supply is bad.

Thank you
 

NoSmoke

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Mar 30, 2020
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Minnesota USA
If it turns out that the PSU is not the actual culprit (and it probably isn't) you should try the 'Minimum Diagnostic Configuration' outlined here:

http://minuszerodegrees.net/5150_5160/MDC/minimum_diag_config.htm

It could easily be a capacitor on the motherboard that is short and preventing the system from running.

Thank you! Should be very helpful as I try to figure it out. I wanted to try the power supply first as it is an easy first option that also wouldn't cost me anything. I thought that I read that the early black power supplies were kinda weak, just thought that would be a good place to start.
 

austinramsay

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Mar 30, 2020
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Yuma, AZ
Let me know how your repair goes and what your solution was if you found one. A 5150 I just picked up (still on the way to me actually) has some 12v rail issues I will have to deal with so any info on repairs may be useful. Yes there's a ton of online info on repairs already but you never know. :) The seller told me the system powers on with the 12v connection unplugged so at least I have something to start with.
 

NoSmoke

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Minnesota USA
Let me know how your repair goes and what your solution was if you found one. A 5150 I just picked up (still on the way to me actually) has some 12v rail issues I will have to deal with so any info on repairs may be useful. Yes there's a ton of online info on repairs already but you never know. :) The seller told me the system powers on with the 12v connection unplugged so at least I have something to start with.

I will definitely let you know. My electronic knowledge is dwarfed by my ambition but I'm learning. I have gotten a lot of info from minuszerodegrees, but I have also been watching repairs on similar machines. On my 5150, I have a known good power supply, Tested in a 5160, so check.
The directions for testing the voltage at the plug left me a little unsure so I tested voltage in other places, like the ram chips and the cpu, and could barely get any reading. I am thinking tantalum capacitor.
Now, the real question: should I be able to check continuity between ground and all the power rails on the 2 power plugs on the motherboard? And should I get no continuity if the caps are doing there jobs?
That's where my heads at but I am still learning. Any input welcomed and appreciated!
 

Stone

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Nov 3, 2009
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South Jersey, USA
Now, the real question: should I be able to check continuity between ground and all the power rails on the 2 power plugs on the motherboard? And should I get no continuity if the caps are doing there jobs?
While I'm not so sure about that, as caps can have other issues as well, I am sure that a shorted cap on the 12V rail will show as no resistance.
 

NoSmoke

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Joined
Mar 30, 2020
Messages
11
Location
Minnesota USA
Let me know how your repair goes and what your solution was if you found one. A 5150 I just picked up (still on the way to me actually) has some 12v rail issues I will have to deal with so any info on repairs may be useful. Yes there's a ton of online info on repairs already but you never know. :) The seller told me the system powers on with the 12v connection unplugged so at least I have something to start with.

So to update, I got it fixed. It was the tantalum on the 12v rail on bank 3 of the ram chips. I still wasn't sure which tantalum was bad so I ordered 6 and the bad one was the third one I changed.
 
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