A2000 PSU refurbish

Vypr · 17 May 2019, 01:13

Just got an Amiga 2000, my first big box Amiga. Seller advised it was non functional with a green screen at boot. The battery had been removed and the area cleaned.
On receiving the unit the first thing I did was to remove the PSU and drives.
The area around the battery looks clean but there was some light corrosion on the three pins on the CPU nearest the battery.

Before I powered the board I thought I'd test the PSU first and I am glad I did.
All the power rails are showing serious voltage fluctuation. 5v bounces between 3 and 5.5v, 12v bounces between 10 and 11.5, -12v shows between 0 and -3 and -5 is between -3 and 5v.

The fan is also speeding up and slowing down so I can only guess that the line caps are completely gubbed.

I have got an ATX adaptor on order but I would like to get this PSU reconditioned. To that end I'm afraid my google-fu has come up short so does anyone know th we list of caps needed to swap on these PSU's?

Jope · 17 May 2019, 07:42

You already have the PSU out, so I guess you could look at the caps and make a cap list for the rest of us? :-)

dalek · 17 May 2019, 08:11

Yeah, there are a few different "innards" as the PSUs were made by different no-name suppliers - I wouldn't trust any single cap kit I found anyway.

But, when I looked at the cost of properly recapping mine I just replaced the innards with an Ian Stedman ATX adaptor and spare ATX innards. Not much value in preserving retro PSU designs.

Vypr · 17 May 2019, 21:14

Quote:

Originally Posted by Jope

You already have the PSU out, so I guess you could look at the caps and make a cap list for the rest of us? :-)

Since you asked so nicely:

Model : PhiHong PSM-2000 Rev-F1

C10 100 uF 35V
C12 47 uF 25V
C17 220 uF 25V
C18 47 uF 25V
C19 47 uF 25V
C20 4700 uF 16V
C21 4700 uF 16V
C22 1 uF 50V
C23 4700 uF 10V
C24 4700 uF 10V
C25 4700 uF 10V
C28 1 uF 50V
C32 47 uF 16V
C6 680 uF 200V
C7 680 uF 200V

Jope · 18 May 2019, 07:59

Thank you kind sir. :-)

Hewitson · 18 May 2019, 08:24

Phi Hong... Sounds like a quality brand. Possibly German?

Vypr · 18 May 2019, 15:19

In case it helps, here are the positions of the caps as well.

Vypr · 21 May 2019, 19:25

Well, I replaced all the caps on the PSU which made no difference to the problem. Voltage was fluctuating badly. Checked all the diodes and they seemed OK. On a passing whim I disconnected the fan and now the bloody thing works!

Agilent · 21 May 2019, 19:31

Caps is not just caps. Did you check datasheet of the old ones and matched new ones with better or same ripple current specs and same or little lower ESR

Vypr · 23 May 2019, 00:09

Quote:

Originally Posted by Agilent

Caps is not just caps. Did you check datasheet of the old ones and matched new ones with better or same ripple current specs and same or little lower ESR

Matched them as closely to the poriginal as possible., there's something hinky goin on in there as when I put a brand new fan in place suddenly the problem reappeared. Have decided to give up and get an ATX PSU adaptor instead.

Now I have to troubleshoot the chip RAM problems.

madcap · 23 May 2019, 00:49

I replaced my PSU with an ATX one 2 years ago and I posted a tutorial on github. If you're interested, here it is:
https://github.com/tfve/a2000atx

dalek · 23 May 2019, 01:28

Nice guide - great writeup.

I did the same but stupidly didn't take any pictures. What I did was put the adaptor inside the PSU case - drilled holes in the left hand side - if you look at your second to last picture it went flat against the left panel on the inside. That way the wires running out look original.

Only issue with that is to try and keep the bolts flush on the outside, as on the A2000 a card in the CPU slot gets very close to the PSU. Next time I take it out I will take some photos!

EDIT: oh - and be careful - anti-static bags can be conductive!

Vypr · 23 May 2019, 10:32

Was that yours? Yes, I had a look at that but unfortunately Ian's ATX adaptor is out of stock, I have ordered an ATX adaptor from Amigakit but they seem to be very slow to acknowledge orders these days as it has been sitting in Pending for a week now.

madcap · 23 May 2019, 10:36

Quote:

Originally Posted by dalek

I did the same but stupidly didn't take any pictures. What I did was put the adaptor inside the PSU case - drilled holes in the left hand side - if you look at your second to last picture it went flat against the left panel on the inside. That way the wires running out look original.

EDIT: oh - and be careful - anti-static bags can be conductive!

I've been thinking of putting the adaptor inside the PSU too, because it's getting really crowded inside the Amiga. I have a Vampire with several extender cables in there (cf, hdmi, ethernet, microsd...)

Please post some photos of your PSU when you can.

Thanks for the heads up regarding the anti-static bags!

Jope · 23 May 2019, 11:38

When I did A2000 PSU replacements, I just swapped the AT/ATX PSU inside the original case and soldered the A2000 power harness to the new PSU's circuit board in place of the wires that went to the original motherboard power connector. No need for any adapters - you already have the required cable.

Vypr · 23 May 2019, 13:03

I have the cable but no spare PSU. Thought I could take one from one of the old PCs at work that are being disposed of but they are all HP DC8000's with proprietary PSU's that don't have a 5V line on them

dalek · 23 May 2019, 13:43

Quote:

Originally Posted by Jope

When I did A2000 PSU replacements, I just swapped the AT/ATX PSU inside the original case and soldered the A2000 power harness to the new PSU's circuit board in place of the wires that went to the original motherboard power connector. No need for any adapters - you already have the required cable.

Only things you miss out with there are the -5V line (used by some zorro expansions?) and the tick signal (if you don't want to use the video signal tick jumper option).

Jope · 23 May 2019, 13:47

Quote:

Originally Posted by dalek

Only things you miss out with there are the -5V line (used by some zorro expansions?) and the tick signal (if you don't want to use the video signal tick jumper option).

Indeed. I selected a PSU with -5 and moved the tick jumper, as I didn't need a stable tick for anything.

obitus1990 · 23 May 2019, 16:37

Quote:

Originally Posted by Vypr

Was that yours? Yes, I had a look at that but unfortunately Ian's ATX adaptor is out of stock, I have ordered an ATX adaptor from Amigakit but they seem to be very slow to acknowledge orders these days as it has been sitting in Pending for a week now.

There is a guy on Amibay selling the IanSteadman adapter as well. He is based in Germany.

17 May 2019, 01:13	#1
Vypr Registered User Join Date: Dec 2016 Location: East Kilbride, Scotland Posts: 451	A2000 PSU refurbish Just got an Amiga 2000, my first big box Amiga. Seller advised it was non functional with a green screen at boot. The battery had been removed and the area cleaned. On receiving the unit the first thing I did was to remove the PSU and drives. The area around the battery looks clean but there was some light corrosion on the three pins on the CPU nearest the battery. Before I powered the board I thought I'd test the PSU first and I am glad I did. All the power rails are showing serious voltage fluctuation. 5v bounces between 3 and 5.5v, 12v bounces between 10 and 11.5, -12v shows between 0 and -3 and -5 is between -3 and 5v. The fan is also speeding up and slowing down so I can only guess that the line caps are completely gubbed. I have got an ATX adaptor on order but I would like to get this PSU reconditioned. To that end I'm afraid my google-fu has come up short so does anyone know th we list of caps needed to swap on these PSU's?

18 May 2019, 15:19	#7
Vypr Registered User Join Date: Dec 2016 Location: East Kilbride, Scotland Posts: 451	In case it helps, here are the positions of the caps as well. Attached Thumbnails

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
a2000 psu replacement	m1chtheunlikely	support.Hardware	11	12 October 2018 10:00
New Caps for an A2000 PSU?	jamiem	support.Hardware	3	08 August 2012 09:22
A2000...possible PSU issue?	Fingerlickin_B	support.Hardware	24	30 September 2010 10:25
A2000 PSU overload...or something else?	Fingerlickin_B	support.Hardware	4	02 January 2009 08:23
Pin 14 on A2000 PSU?	staticgerbil	support.Hardware	5	13 August 2003 12:04

17 May 2019, 07:42	#2
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,861	You already have the PSU out, so I guess you could look at the caps and make a cap list for the rest of us? :-)

17 May 2019, 08:11	#3
dalek Registered User Join Date: Nov 2014 Location: NSW/Australia Posts: 462	Yeah, there are a few different "innards" as the PSUs were made by different no-name suppliers - I wouldn't trust any single cap kit I found anyway. But, when I looked at the cost of properly recapping mine I just replaced the innards with an Ian Stedman ATX adaptor and spare ATX innards. Not much value in preserving retro PSU designs.

18 May 2019, 07:59	#5
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,861	Thank you kind sir. :-)

18 May 2019, 08:24	#6
Hewitson Registered User Join Date: Feb 2007 Location: Melbourne, Australia Age: 41 Posts: 3,772	Phi Hong... Sounds like a quality brand. Possibly German?

21 May 2019, 19:25	#8
Vypr Registered User Join Date: Dec 2016 Location: East Kilbride, Scotland Posts: 451	Well, I replaced all the caps on the PSU which made no difference to the problem. Voltage was fluctuating badly. Checked all the diodes and they seemed OK. On a passing whim I disconnected the fan and now the bloody thing works!

21 May 2019, 19:31	#9
Agilent Registered User Join Date: Jan 2015 Location: Gentofte/Denmark Posts: 104	Caps is not just caps. Did you check datasheet of the old ones and matched new ones with better or same ripple current specs and same or little lower ESR

23 May 2019, 00:49	#11
madcap Registered User Join Date: May 2014 Location: Lisbon / Portugal Posts: 61	I replaced my PSU with an ATX one 2 years ago and I posted a tutorial on github. If you're interested, here it is: https://github.com/tfve/a2000atx

23 May 2019, 01:28	#12
dalek Registered User Join Date: Nov 2014 Location: NSW/Australia Posts: 462	Nice guide - great writeup. I did the same but stupidly didn't take any pictures. What I did was put the adaptor inside the PSU case - drilled holes in the left hand side - if you look at your second to last picture it went flat against the left panel on the inside. That way the wires running out look original. Only issue with that is to try and keep the bolts flush on the outside, as on the A2000 a card in the CPU slot gets very close to the PSU. Next time I take it out I will take some photos! EDIT: oh - and be careful - anti-static bags can be conductive!

23 May 2019, 10:32	#13
Vypr Registered User Join Date: Dec 2016 Location: East Kilbride, Scotland Posts: 451	Was that yours? Yes, I had a look at that but unfortunately Ian's ATX adaptor is out of stock, I have ordered an ATX adaptor from Amigakit but they seem to be very slow to acknowledge orders these days as it has been sitting in Pending for a week now.

23 May 2019, 11:38	#15
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,861	When I did A2000 PSU replacements, I just swapped the AT/ATX PSU inside the original case and soldered the A2000 power harness to the new PSU's circuit board in place of the wires that went to the original motherboard power connector. No need for any adapters - you already have the required cable.

23 May 2019, 13:03	#16
Vypr Registered User Join Date: Dec 2016 Location: East Kilbride, Scotland Posts: 451	I have the cable but no spare PSU. Thought I could take one from one of the old PCs at work that are being disposed of but they are all HP DC8000's with proprietary PSU's that don't have a 5V line on them

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)