A4000 PSU voltage question

jumpinjackson

jumpinjackson

Member
AmiBayer
Joined
May 12, 2015
Posts
333
Country
UK
Region
Berkshire
After getting them recapped and repaired, I got my A4000 boards back.
Since it has been a long while from last power on, before installing them I decided to take some measurements from the PSU.

-12V pole reads -12.09V - OK
+5V pole reads +5.01V - OK
+12V pole reads +11.21V ...that-s about a -7% tolerance from the expected +12V... :unsure:

I haven't put the board back in yet.

Any suggestion/advise?

Thanks to All 🙌
 
jumpinjackson said:
After getting them recapped and repaired, I got my A4000 boards back.
Since it has been a long while from last power on, before installing them I decided to take some measurements from the PSU.

-12V pole reads -12.09V - OK
+5V pole reads +5.01V - OK
+12V pole reads +11.21V ...that-s about a -7% tolerance from the expected +12V... :unsure:

I haven't put the board back in yet.

Any suggestion/advise?

Thanks to All 🙌
Click to expand...
Did you not get the PSU recapped?
 
Boing-ball said:
I had similar issues with a Liteon PSU. In the end I upgraded to a Corsair 450 SF PSU with the leads and PSU holder off sellers on here. The issue is the age on the older PSU’s.
Click to expand...

Thanks, I have 2 A4000, I'll check the other case/PSU tomorrow to see what readings I can get from the other, just ot compare.
 
Did you measure it with a load (harddrive or whatever)?
If yes the +5V seems good enough here. +12V i don't know if that is of importance.
The A4000 design makes that there is a huge loss on the +5V line throghout the computer, to the point of not being able to power an optical mouse out of the DB9 port with a tired psu.
Using a recapped PSU has been a great improvement on my main rig.
 
Xanxi said:
Did you measure it with a load (harddrive or whatever)?
If yes the +5V seems good enough here. +12V i don't know if that is of importance.
The A4000 design makes that there is a huge loss on the +5V line throghout the computer, to the point of not being able to power an optical mouse out of the DB9 port with a tired psu.
Using a recapped PSU has been a great improvement on my main rig.
Click to expand...

I'll have a look at recapping or replacing the PSU...
 
I did a few more measurements:

ExpectedLoad (FDD + 3.5"HDD)Tolerance (± 5%)
+12V+11.57V
3.58%​
-12V-11.80V
1.67%​
+5V+4.96V
0.8%​

I think I could plug the mobo and would work. I'll have to think about if recapping is best...
 
Not bad. Recapping old stuff is always welcome. Those PSU are very old (30 years).
 
My PSUs are Skynet, I've found this list for recapping on an EAB old thread:

C6 22uF 25v, 5mm pitch, 5mm dia Rubycon 50YXG22MEFC5X11
C7, C8 330uF 200v, 10mm pitch, 22mm dia Kemet ELG337M200AQ2AA
C21 1200uF 16v, 5mm pitch, 10mm dia Rubycon 16YXG1200MEFC10X23
C22 1000uF 10v, 5mm pitch, 10mm dia Rubycon 16YXG1000MEFC10X20
C25, C26 330uF 25v, 5mm pitch, 8.5mm dia Rubycon 25YXG330MEFC10X12.5
C27, C29 47uF 25v, 5mm pitch, 6.5mm dia Rubycon 25YXF47MEFC5X11
C31 120uF 25v, 5mm pitch, 6.5mm dia Rubycon 35YXG120MEFC8X11.5

All of the above seem avaialble, for the one below though I can't seem to find the right component, only 50V capacitors...

C34 1uF / 25V 5mm
 
Here is a chart i put together for a A4000D Skynet PSU - It has the Digikey part numbers in coloumn I - hope this helps.

1714202460994.png
 
Koolvin said:
Here is a chart i put together for a A4000D Skynet PSU - It has the Digikey part numbers in coloumn I - hope this helps.

View attachment 2485352
Click to expand...
Hey, many thanks for this.
I got a little impatient and ordered from digikey most of the original ones (+- a couple of replacements), I think your list is definitely better as it include better capacitors, but I guess for the next 15 years I should be fine anyway.

Thanks again for the detailed list, I have saved it and will keep it! 👏
 
jumpinjackson said:
Hey, many thanks for this.
I got a little impatient and ordered from digikey most of the original ones (+- a couple of replacements), I think your list is definitely better as it include better capacitors, but I guess for the next 15 years I should be fine anyway.

Thanks again for the detailed list, I have saved it and will keep it! 👏
Click to expand...
No worries at all ! Thank you for the feedback and be careful inside that PSU whatever you do.
 
Thaks
Koolvin said:
No worries at all ! Thank you for the feedback and be careful inside that PSU whatever you do.
Click to expand...
Thanks! I've already ensured the caps are fully discharged, I'll try not to fry myself ⚡
 
Last edited:
You must log in or register to reply here.

Similar threads

C
A1000 PSU Voltage Questions
Replies
1
Views
97
ChrisUnionNJ
ChrisUnionNJ
Back
Top Bottom