Old AT PSU Is is worth recapping?

[blacksvk]

Hello, I use Morex MXR-200PS PSU in my retro Pentium 1 PC. It is working fine (so far), however it is very loud - so I desided to open it up and I discovered it is full of crappy caps. Pictures: http://imgur.com/a/eSO1E

I would like to know your opinios about this PSU, because I am not PSU expert. Do you think it is worth to recap it and replace the fan, or it is just better to look for another(better) AT PSU?

[pdavid]

Re: Old AT PSU Is is worth recapping?

Hi blavksvk!

This psu is a ok AT unit. Can output 200W no problem. I see it sometimes with different capacitors and even a fan controller board installed. Replace all capacitors on the secondary. Maybe swap the two primaries with some 470 capacity ones...

[kc8adu]

Re: Old AT PSU Is is worth recapping?

loud is the fan.
but i spy crapxon.change them all.

[CapLeaker]

Re: Old AT PSU Is is worth recapping?

loud is the fan.
but i spy crapxon.change them all.

x2

[blacksvk]

Re: Old AT PSU Is is worth recapping?

Thanks, I will change them!

I disassembled the PSU completely and I started inspecting cap values.

C5: 200V 330uF 85°C TOSIN 
C6: 200V 330uF 85°C TOSIN
C10: 35V 4.7uF 105°C CapXon KM
C14: ??????????
C15: 16V 2200uF 105°C CapXon KM
C16: 16V 1000uF 105°C CapXon KM
C17: 16V 2200uF 105°C CapXon KM
C18: 6.3V 6800uF 105°C CapXon KM
C19: 16V 220uF 105°C CapXon KM
C20: 35V 4.7uF 105°C CapXon KM
C21: 16V 4.7uF 105°C CapXon KM
C24: 25V 10uF 105°C CapXon KM
C25: 35V 4.7uF 105°C CapXon KM
C26: 50V 4.7uF 105°C CapXon KM
C29: 25V 22uF 105°C CapXon KM
C30: 25V 10uF 105°C CapXon KM
C31: 35V 4.7uF 105°C CapXon KM
C42: 35V 4.7uF 105°C CapXon KM

I cannot see the C14 values, because the C14 cap is covered in some kind of sleeve (it looks similar to heat shrink tube), see photos here: http://imgur.com/8M3pH4m , http://imgur.com/P8SIpAE . Does that sleeve serve any purpose? Do I need to keep that sleeve for replacement cap, or can I just cut that sleeve to reveal the cap inside it ?

Also... I found out, that there ale a lot of small caps, like the C27 (the green one - see this photo: http://imgur.com/37eMlUs). Should I change these as well?

[PeteS in CA]

Re: Old AT PSU Is is worth recapping?

This may sound odd, but be careful not to replace the output capacitors with parts that are too good, that PSU is about 25 years old, and electrolytic capacitor technology has advanced quite a bit since then. The parts I'd recommend, in order of preference would be:

1. Nichicon PS series or Rubycon YXF series;

2. Nichicon PM series;

3. Nichicon PJ series or Nippon Chemicon (United Chemicon) LXVseries.

PS and PM are ROHS compliant versions of parts Nichicon produced when that PSU was made; Rubycon YXF series is of that time as well. PJ and LXV were the next newer series.

[jiroy]

Re: Old AT PSU Is is worth recapping?

Being a good stable source of 12 volts , 3 volts and 5 volts , with high Amperage rating of 6 to 10 A , definitely usable for all different electronic fields , PSUs are always worth repairing .

[blacksvk]

Re: Old AT PSU Is is worth recapping?

These are the caps I want to change:

C10: 35V 4.7uF 105°C CapXon KM => 35V 4.7uF Nichicon UPS UPS1V4R7MDD1TD
C14: 16V 220uF 105°C CapXon KM => 16V 220uF Nichicon UPS UPS1C221MPD1TD
C15: 16V 2200uF 105°C CapXon KM => 16V 2200uF Nichicon UPS UPS1C222MHD1TO
C16: 16V 1000uF 105°C CapXon KM => 16V 1000uF NIchicon UPS UPS1C102MPD1TD
C17: 16V 2200uF 105°C CapXon KM => 16V 2200uF Nichicon UPS UPS1C222MHD1TO
C18: 6.3V 6800uF 105°C CapXon KM => 6.3V 6800uF Nichicon UPS UPS0J682MHD1TN 
C19: 16V 220uF 105°C CapXon KM => 16V 220uF Nichicon UPS UPS1C221MPD1TD
C20: 35V 4.7uF 105°C CapXon KM => 35V 4.7uF Nichicon UPS UPS1V4R7MDD1TD
C21: 16V 4.7uF 105°C CapXon KM => 25V 4.7uF Nichicon UPS UPS1E4R7MDD1TD
C24: 25V 10uF 105°C CapXon KM => 25V 10uF Nichicon UPS UPS1E100MDD1TD 
C25: 35V 4.7uF 105°C CapXon KM => 35V 4.7uF Nichicon UPS UPS1V4R7MDD1TD
C26: 50V 4.7uF 105°C CapXon KM => 50V 4.7uF Nichicon UPS UPS1H4R7MDD1TD
C29: 25V 22uF 105°C CapXon KM => 25V 22uF Nichicon UPS UPS1E220MDD1TD
C30: 25V 10uF 105°C CapXon KM => 25V 10uF Nichicon UPS UPS1E100MDD1TD 
C31: 35V 4.7uF 105°C CapXon KM => 35V 4.7uF Nichicon UPS UPS1V4R7MDD1TD
C42: 35V 4.7uF 105°C CapXon KM => 35V 4.7uF Nichicon UPS UPS1V4R7MDD1TD

Can anyone check it? Also, it is OK to change 16V 4.7uF to 25V 4.7uF?

[stj]

Re: Old AT PSU Is is worth recapping?

no problem on that voltage upgrade.
i'm surprised you even found that, normally a good 4.7uf cap starts at 35v or even 50v these days.

[Stefan Payne]

Re: Old AT PSU Is is worth recapping?

I woudn't care and just order 50V/4.7uF Parts and use that instead. Those things are more common these days so I'd rather not bother with lower voltage ones.