English Amiga Board


Go Back   English Amiga Board > Support > support.Hardware

 
 
Thread Tools
Old 22 February 2010, 14:25   #1
8bitbubsy
Registered User

8bitbubsy's Avatar
 
Join Date: Sep 2009
Location: Norway
Age: 28
Posts: 1,255
Send a message via MSN to 8bitbubsy
Changing capacitors in Amiga power supplies

I have this old trusty A500 PSU brick which always gives a good and stable voltage rail, I love it! However, it's very very old so it might be a bit sick.
I know very well the saying "Don't fix what is not broken", but capacitors are known to fail over time and especially the very old ones!

Capacitor list (POWER SUPPLY A 500 P/NO. 312 503- 03):
2x 470F 25v electrolytic through-hole
1x 4700F 25v electrolytic through-hole
1x 4700F 16v electrolytic through-hole
3x 22F 25v electrolytic through-hole

Futurlec order list:
2x 4700F 25v
3x 22F 50v
2x 470F 25v

Oh, and another thing.. When this PSU has ran for half an hour or so it starts to smell like "80s bite the dust & plastic" or something like that.. It's not a fault, it's the case.. How can I remove this? Just wash it?


Last edited by 8bitbubsy; 22 February 2010 at 14:46.
8bitbubsy is offline  
AdSense AdSense  
Old 22 February 2010, 15:38   #2
jbenam
Italian Amiga Zealot

 
Join Date: Jan 2009
Location: Italy
Age: 30
Posts: 1,227
I was going to do the same thing with my A1200 brick (one of those black ones)!

Sadly it started having pretty instable voltages not too long ago (luckily I switched over to my Micronik Infinitiv PSU just some days later) and I thought of changing capacitors on it. Already got a bunch of em, but I preferred to wait for a Desoldering Gun station to do this work. Now that I have one, I might do it soon

Good luck!
jbenam is offline  
Old 22 February 2010, 15:54   #3
Thorham
Computer Nerd

Thorham's Avatar
 
Join Date: Sep 2007
Location: Rotterdam/Netherlands
Age: 41
Posts: 2,971
Isn't it a better idea to buy a new peecee psu and mod it using the cable from the Amiga psu? Unless you want to keep things as original as possible, this might be a better option.
Thorham is offline  
Old 22 February 2010, 16:03   #4
8bitbubsy
Registered User

8bitbubsy's Avatar
 
Join Date: Sep 2009
Location: Norway
Age: 28
Posts: 1,255
Send a message via MSN to 8bitbubsy
Quote:
Originally Posted by Thorham View Post
Isn't it a better idea to buy a new peecee psu and mod it using the cable from the Amiga psu? Unless you want to keep things as original as possible, this might be a better option.
Well.. I've tried that, but all the PSUs I have seem to have a pretty low 5v voltage rail... The original Commodore PSUs are perfect (5.04v on mine)
8bitbubsy is offline  
Old 22 February 2010, 16:17   #5
Thorham
Computer Nerd

Thorham's Avatar
 
Join Date: Sep 2007
Location: Rotterdam/Netherlands
Age: 41
Posts: 2,971
Quote:
Originally Posted by 8bitbubsy View Post
Well.. I've tried that, but all the PSUs I have seem to have a pretty low 5v voltage rail... The original Commodore PSUs are perfect (5.04v on mine)
Oh, I didn't know that. Is that something that can cause damage to an Amiga (I us an AT PSU to power an A1200, CD rewriter and HD)?
Thorham is offline  
Old 22 February 2010, 16:26   #6
8bitbubsy
Registered User

8bitbubsy's Avatar
 
Join Date: Sep 2009
Location: Norway
Age: 28
Posts: 1,255
Send a message via MSN to 8bitbubsy
I doubt it, but it's not healthy in any way for it... You can get funky results and unstability, as far as I know. Always good to have a precise voltage rating My other PSUs has like 4.66v on the 5v rail...
12.0xv and 5.0xv is perfect
8bitbubsy is offline  
Old 22 February 2010, 16:38   #7
Thorham
Computer Nerd

Thorham's Avatar
 
Join Date: Sep 2007
Location: Rotterdam/Netherlands
Age: 41
Posts: 2,971
Quote:
Originally Posted by 8bitbubsy View Post
I doubt it, but it's not healthy in any way for it... You can get funky results and unstability, as far as I know. Always good to have a precise voltage rating My other PSUs has like 4.66v on the 5v rail...
12.0xv and 5.0xv is perfect
Okay, thanks for letting me know I guess I should do some measurements when I replace my dead A1200. Perhaps spending more on a high quality peecee PSU would make a difference.
Thorham is offline  
Old 23 February 2010, 01:05   #8
Loedown
Precious & fragile things

 
Join Date: Feb 2009
Location: Victoria, Australia
Posts: 1,926
I've had no issue with using AT style power supplies, but then again, I only use new supplies and decent branded ones, they don't cost much more and you can be assured that if the thing goes tits up, you're more likely not to blow your Amiga hardware to kingdom come. Ask me the story about my sister's PC and the amazing melting RAM chips.

Don't ask, I'll write it anyway, she left her PC on overnight and came out in the morning to find a very dead PC, so I got it and opened it up, it had blown every single card in the machine, literally blown chunks out of the chips. The RAM chips had gotten so hot that they'd melted their own solder and moved on the simms. I could only save two things from the whole system, the DVD laser and the CPU, everything else was fried. So don't use cheap power supplies.
Loedown is offline  
Old 01 February 2016, 17:02   #9
Franchute13
Registered User
Franchute13's Avatar
 
Join Date: Feb 2013
Location: Argentina
Posts: 230
Hi.
Use this thread to detail capacitors using this PSU
Model:
A 391 029-03_rev
Photo:
http://hostthenpost.org/uploads/7786...9398c50a9b.jpg

List:
3 x 47uFx35V 85C
1 x 82uFx35V 105C
2 x 1000uFx10V 105C
1 x 220uFx35V 105C
1 x 1uFx50V 85C
1 x 33uFx400V 85C
Franchute13 is offline  
Old 01 February 2016, 17:37   #10
8bitbubsy
Registered User

8bitbubsy's Avatar
 
Join Date: Sep 2009
Location: Norway
Age: 28
Posts: 1,255
Send a message via MSN to 8bitbubsy
Oh wow, I was younger and dumb back then, in the first post...

1) The 80s smell is not a bad thing!
2) You should use low ESR capacitors in a switching power supply. Also, futurlec.com tends to give you the cheapest capacitors ever. One time I got a batch of fake Rubycons from them with high ESR, all of them. I have a feeling that their Samxon stuff is fake too, because they have high ESR too. I've seen real Samxon stuff in some good (!) PSUs, and they look to be of more quality. Could be a different series.. Anyways, never buy from futurlec.com if you want to do a proper recap job that should last and be good.
8bitbubsy is offline  
Old 01 February 2016, 18:29   #11
dlfrsilver
CaptainM68K-SPS France
dlfrsilver's Avatar
 
Join Date: Dec 2004
Location: Melun nearby Paris/France
Age: 40
Posts: 7,219
Send a message via MSN to dlfrsilver
guys i changed the capacitors for better ones in my own PSU's and the result is very neat !!!

Don't throw away your old PSUs, restore them, buy some high quality capacitors (rubycon, or nichicon), and replace them.

It's amazing how great the display got better once i did the change on my A500 PSU

Just use a screwdriver to discharge the parts, and go disolder the old farts !
dlfrsilver is offline  
Old 01 February 2016, 19:14   #12
Zetr0
Ya' like it Retr0?
Zetr0's Avatar
 
Join Date: Jul 2005
Location: United Kingdom
Age: 43
Posts: 9,769
@Thread

I would humbly suggest replacing for 105c (Or higher) rated capacitors - always go for a good brand, like rubycon, nichicon or my favourite panasonic.

If your hearing a buzzing sound its quite likely the transformer coils, these can be replaced - (you would require a 2 tap module - [12v and 5v], the rest is rectified on the power supply PCB. To be honest though a "drop in" replacement might be tricky to source.

If you are having intermittent issues but still reporting good voltages = current leakage could be an issue and at that point it would prudent to replace the rectifier diodes. like for like would be the best thing here.

Last edited by Zetr0; 01 February 2016 at 19:28.
Zetr0 is offline  
Old 01 February 2016, 19:20   #13
mech
Registered User
mech's Avatar
 
Join Date: Mar 2009
Location: texas,usa
Posts: 179
Quote:
Originally Posted by Zetr0 View Post
@Thread

I would humbly suggest replacing for 105c (Or higher) rated capacitors - always go for a good brand, like rubycon, nichicon or my favourite panasonic.
I second the Panasonic! their long life caps are excellent.
mech is offline  
AdSense AdSense  
 


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

Similar Threads
Thread Thread Starter Forum Replies Last Post
A1200 power input capacitors ShK support.Hardware 21 23 July 2013 23:14
UK/Australian power supplies A1200 twenty90seven support.Hardware 2 10 June 2013 05:06
Amiga 4000D PSU capacitors list lostrego support.Hardware 9 26 July 2011 21:13
Killer power supplies Quagliarulo support.Hardware 27 11 April 2011 01:50
Power Supplies Mick_AKA support.Hardware 14 17 May 2003 14:06

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +2. The time now is 15:49.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Page generated in 0.26140 seconds with 14 queries