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How to test a power adapter


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#1 Atarifever OFFLINE  

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Posted Sat Apr 20, 2019 7:22 AM

Quick and simple question: How do I use a multimetre to test if my 7800 adapter is broken or if there is a problem with the 7800 itself.  Everything I find in search is more related to the 2600 and not the 7800s weird adapter.  Thanks.

 

 



#2 DrVenkman OFFLINE  

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Posted Sat Apr 20, 2019 7:49 AM

Well, just set your meter to the appropriate DC voltage range and check it. The stock 7800 PSU is 9VDC, if I recall correctly. My meter has a range for 6V, and the next one is 60V. So I’d set the meter to 60VDC, put the tip of one probe into one side of the weird little plug, and one into the other and see what it reads. These power supplies are typically not regulated so they’ll read high when not under load.

#3 -^CrožBow^- OFFLINE  

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Posted Sat Apr 20, 2019 8:28 AM

Quick and simple question: How do I use a multimetre to test if my 7800 adapter is broken or if there is a problem with the 7800 itself.  Everything I find in search is more related to the 2600 and not the 7800s weird adapter.  Thanks.

 

 

Venkman is correct. Most of the 7800 PSUs I see will actually show to generate about 12 - 15v straight from the adapter itself. The one I use on my test bench puts out 14.66v 



#4 Atarifever OFFLINE  

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Posted Sat Apr 20, 2019 1:13 PM

Venkman is correct. Most of the 7800 PSUs I see will actually show to generate about 12 - 15v straight from the adapter itself. The one I use on my test bench puts out 14.66v 

Thanks for the help guys.  I got about 14 (13.something).  I assume this means my adapter is okay.  Any way for me to test where the fault is in the 7800? 

I'm making another attempt at learning to solder etc. and figure with a couple busted 7800s and a bunch of broken old cable boxes and gameboys to experiment with first, now's as good a time as any to try to figure some things out.


Edited by Atarifever, Sat Apr 20, 2019 1:13 PM.


#5 Mitch OFFLINE  

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Posted Sat Apr 20, 2019 1:54 PM

Check the power at the voltage regulator. It is attached to the big heatsink behind the cart port.

Mitch




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