NAC PSU weak voltage...

ahcmetal

ahcmetal

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I hooked up my NAC PSU today to check the voltages...

I'm getting good 120v, however my 12v was jumping between 10-10.8v, my +5v was jumping between 4-4.8v with the adjustment screw turned all the way up...and my -5v was just reading 0...unless I was using my meter wrong when i was checking for that...

Here's some pics, it's a 400-5198-01Y:
http://wiki.arcadeotaku.com/w/New_Astro_City_PSUs

Astro PSU.1.jpgAstro PSU.2.jpg

Any input on how to fix this up? Here's the numbers off the 3 chips that are attached to the heat sinks:

K2236 5K...I think this is a voltage regulator?

61 D15SCA4M...has diode symbols on it, I think it's a rectifier?

58 D5LC20U...also has diode symbols on it...

Cap list:

50v 0.47uf
25v 47uf
50v 10uf
200v 330uf
10v 6800uf
10v 6800uf
16v 2200uf
50v 10uf
25v 100uf

Do any of you guys have any advice on what you think I should replace to get these voltages back to where they are supposed to be??
 
Westcb

Westcb

Give an Azn, A Break Here!,
Joined
May 17, 2012
Posts
1,190
ahcmetal said:
I hooked up my NAC PSU today to check the voltages...



I'm getting good 120v, however my 12v was jumping between 10-10.8v, my +5v was jumping between 4-4.8v with the adjustment screw turned all the way up...and my -5v was just reading 0...unless I was using my meter wrong when i was checking for that...



Here's some pics, it's a 400-5198-01Y:

http://wiki.arcadeotaku.com/w/New_Astro_City_PSUs



View attachment 29585View attachment 29586



Any input on how to fix this up? Here's the numbers off the 3 chips that are attached to the heat sinks:



K2236 5K...I think this is a voltage regulator?



61 D15SCA4M...has diode symbols on it, I think it's a rectifier?



58 D5LC20U...also has diode symbols on it...



Cap list:



50v 0.47uf

25v 47uf

50v 10uf

200v 330uf

10v 6800uf

10v 6800uf

16v 2200uf

50v 10uf

25v 100uf



Do any of you guys have any advice on what you think I should replace to get these voltages back to where they are supposed to be??
Click to expand...


I have rebuilt two NAC power supplies, I start with all caps that's a must, after I check voltages and if it's not steady I change the voltage regulators. Last one I did 5v was fine, but 12v was at like 4 or less. Completely crapped out but after putting in a new one everything was great again. So start with caps then if needed swap the regulators. Not much to them so between those two things chances are you will be good to go again.
 
ahcmetal

ahcmetal

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10 Year Member
Joined
Aug 25, 2010
Posts
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That was kind of my assumption as well...I ordered up the caps last night...

I didn't have much luck googling the K2236 regulator though...anybody know where to find a compatible replacement for that??
 
Westcb

Westcb

Give an Azn, A Break Here!,
Joined
May 17, 2012
Posts
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ahcmetal said:
That was kind of my assumption as well...I ordered up the caps last night...

I didn't have much luck googling the K2236 regulator though...anybody know where to find a compatible replacement for that??
Click to expand...


I'm sure I used an NTe equivalent if it's one I replaced, can you post a clear pic of it and I'll see if I can find the receipt in my email of where and what I bought, assuming I changed it...
 
ahcmetal

ahcmetal

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10 Year Member
Joined
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Posts
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Westcb said:
I'm sure I used an NTe equivalent if it's one I replaced, can you post a clear pic of it and I'll see if I can find the receipt in my email of where and what I bought, assuming I changed it...
Click to expand...


Yeah sure thing! I can do the repair...I'm just not smart enough to find a suitable replacement if the manufacture numbers don't match haha!

Any idea if this controls the -5v as well? I wasn't reading anything when I tested that pin...
001.JPG
 
ahcmetal

ahcmetal

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10 Year Member
Joined
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Posts
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