These are the epitome of cost-cutting; recapped or not, I'd be wary about using either of them to power expensive or rare hardware.
(That being said, I'm not sure I'd throw them out because I find very hard parting with any piece of vintage hardware. Maybe give them a good clean and keep them for some junky 286 or 386).

quicknick wrote on 2020-03-23, 12:51:

These are the epitome of cost-cutting;

Well this is what I was thinking, based on my little knowledge.

Still I will clean and keep them. At least I will have some emergency PSUs for cheap builds or quick checks.

Couldn't agree more. Average quality 85° capacitors instead of 105°, minimalistic heatsinks, everything soldered so they didn't have to use connectors, generic PCBs to cut manufacturing costs. Use them at your own risk.

Miphee wrote on 2020-03-24, 10:08:

Couldn't agree more. Average quality 85° capacitors instead of 105°, minimalistic heatsinks, everything soldered so they didn't have to use connectors, generic PCBs to cut manufacturing costs. Use them at your own risk.

Got it and thank you for your opinion! I had similar thoughts on these PSUs, but still I was not sure if I am right.

Putting all the cost-cuts together, I will think twice before connecting these PSUs to anything of value.

Funny thing is that I was originally running one of these PSUs in my first Socket 7, back in 90's, but it was truly a cheap build 😀

The weight of the unit is a telltale sign of quality.

Hipro 250W PSU (supplier of IBM): 1715 g
Mercury 400W PSU: 847 g

It's not a 100% bulletproof test but it's a start.

That 'Emiter' at leas has a quad comparatior set up for power-good signal and voltage rail supervison function. Also components for a temperature controlled fan can be installed onboard. If someone is too bored and has the spares it might be worth beefing up a little. Otherwise both units are junk.

Miphee wrote on 2020-03-24, 11:14:

The weight of the unit is a telltale sign of quality.

True, until you come across one of those with steel or lead slabs bolted in, to make the junk feel heavy 😁

Can this kind of PSU become decent-ish if you add the missing components (Y capacitor, coils, etc) and replace the caps ?
(I had a PSU like this, and I added them from a good ATX PSU I had that died because of a failing fan)

Good question. I have somewhere a bag with 'goodies' recovered from brand-name (but otherwise dead) PSUs: X/Y capacitors, NTCs, line filters and so on. Never got to use one of these to "upgrade" a junky one...

Regarding the wavy pattern appearing with one of the above PSUs, I guess it can be caused by excessive ripple noise on the output(s). In this case, replacing the capacitors near the outputs with quality low-ESR ones, as well as upping the capacitance a notch should help.

quicknick wrote on 2020-03-24, 13:05:

True, until you come across one of those with steel or lead slabs bolted in, to make the junk feel heavy 😁

I just repaired an all-steel PSU and yes, damn thing is heavy. 😁

Deksor wrote on 2020-03-24, 13:30:

Can this kind of PSU become decent-ish if you add the missing components?

A bad PSU can do too much damage to make it worthwhile and it's pretty hard to modify a bad/cheap design.
It's easy to change caps and semiconductors, but it's really hard to get reliable HF transformers with the correct winding. You have to do the winding yourself.
And the hardest part: fitting the better quality parts on the congested PCB.
A quality AT PSU can be found under $10, quality parts for a redesign cost a lot more.

Deksor wrote on 2020-03-24, 13:30:

Can this kind of PSU become decent-ish if you add the missing components (Y capacitor, coils, etc) and replace the caps ?
(I had a PSU like this, and I added them from a good ATX PSU I had that died because of a failing fan)

I guess it could become a decent unit after a rebuild, after all many AT power supplies share the same topology. The problem is that in most cases all of these things would have to be replaced/added:
- Capacitors
- Input filter components (coils, X caps, Y caps)
- Fan
- Diodes in the secondary side (generally these junk units use components with low ratings, and even a pair of discrete diodes for +12V in many cases!)
- Secondary side inductors (usually only the +5V one is populated)
- Cables (at least for the main AT P8/P9 connector, these should be 18AWG, cheap units use 20AWG)
- Find some way to fit larger, decent heatsinks (not always feasible)
- Larger transformer with a compatible footprint, in most cases they are undersized

So, unless you already have the necessary components (probably scavenged from other units) the cost can be too high to be worth it, and some components like the transformer cannot be bought easily (that I know of).

EDIT: as the post above mentions, it's a better option to buy a used good quality PSU and do some basic refurbish by swapping the fan and caps and you're good to go.

Where do you find quality AT psus for 10 bucks ?

Well indeed in my case, I simply scavenged parts from another PSU that was decent.

I usually post an ad on my local electronics forums looking for PSUs and make a bargain.
Local auction sites also offer lots of quality PSUs or PC cases with the PSU included.
It's much harder to get proprietary IBM, Compaq or HP power supplies from the 80's in decent condition.

LuckyPiquel wrote on 2020-03-23, 12:18:

Hi everyone! […]
Show full quote

Hi everyone!

Recently, I've decided to take a look inside my two old AT PSUs (see attached photos). The reasons for that were: (i) I blew up my NOS Startech PS2POWER230 AT PSU 🙁 (see my other post if interested: I blew up my AT PSU, is it worth to repair it?), (ii) I have still two other retro rigs that I want to resurrect (my 386 DX-40 and some 486). In other word I am short on AT PSUs and start thinking about refurbishing these two. They both still work, and only the first one (by EMITER) gives some buzz on the screen while connected (see photo below).

However, before starting my refurb-project, I hope for your opinion on these two PSUs. Are they look to be a decent quality PSUs? I notice that some parts of both boards are unpopulated, that may suggest cost-cutting. Is it therefore worth to refurb them? If so, recapping and changing fans should be enough, or should I replace some other parts as well? Maybe I should just give up on them and go with the ATX + ATXtoAT converter combo? What are your thoughts?

#1 EMITER PSU

Screen buzz due to the EMITER PSU (kind of a wavy vertical buzz)

#2 JNC PSU

There is no sticker with the maximum current for +5V and +12V? WTF

CoffeeOne wrote on 2020-03-24, 16:19:

LuckyPiquel wrote on 2020-03-23, 12:18:

Hi everyone! […]
Show full quote

Hi everyone!

Recently, I've decided to take a look inside my two old AT PSUs (see attached photos). The reasons for that were: (i) I blew up my NOS Startech PS2POWER230 AT PSU 🙁 (see my other post if interested: I blew up my AT PSU, is it worth to repair it?), (ii) I have still two other retro rigs that I want to resurrect (my 386 DX-40 and some 486). In other word I am short on AT PSUs and start thinking about refurbishing these two. They both still work, and only the first one (by EMITER) gives some buzz on the screen while connected (see photo below).

However, before starting my refurb-project, I hope for your opinion on these two PSUs. Are they look to be a decent quality PSUs? I notice that some parts of both boards are unpopulated, that may suggest cost-cutting. Is it therefore worth to refurb them? If so, recapping and changing fans should be enough, or should I replace some other parts as well? Maybe I should just give up on them and go with the ATX + ATXtoAT converter combo? What are your thoughts?

#1 EMITER PSU

Screen buzz due to the EMITER PSU (kind of a wavy vertical buzz)

#2 JNC PSU

There is no sticker with the maximum current for +5V and +12V? WTF

Nope, can't see any additional sticker 😀 right know I feel bit stupid asking about quality of these PSUs, even stickers are missing 😀

Using the occasion I want to consult everyone on one more PSU. This particular one comes from my "new" M24 Olivetti, that sports Pentium and has strange format (I believe LPX). Nonetheless, I was thinking about recapping it, since I am using this computer as my main Socket 7 rig. I opened it today to investigate internals, and share photos here (please see below). The PSU is by Minebea, that I believe was quite a decent company. Inside the PSU looks impressive (comparing to the two above PSUs), being build around Nippon caps (I made full cap list for myself, that you can see below as well). However, the bulk caps may be bit bulgy, or it is just me since their tops are covered in black. Do you think it is a good idea to do the full recap? Also, how do you find the quality of this PSU, based on photos? Moreover, the max power of this PSU is 100 W and I am planning to use in this computer, Voodoo 1 as well as AWE64 Gold. There will be only one HDD and one optical drive. I have already ran such configuration and the reading on the wall was c.a. 65W. Do you think that it is safe to run so much stuff on this 100 W PSU?

LuckyPiquel wrote on 2020-03-24, 21:27:

Using the occasion I want to consult everyone on one more PSU. This particular one comes from my "new" M24 Olivetti, that sports […]
Show full quote

Using the occasion I want to consult everyone on one more PSU. This particular one comes from my "new" M24 Olivetti, that sports Pentium and has strange format (I believe LPX). Nonetheless, I was thinking about recapping it, since I am using this computer as my main Socket 7 rig. I opened it today to investigate internals, and share photos here (please see below). The PSU is by Minebea, that I believe was quite a decent company. Inside the PSU looks impressive (comparing to the two above PSUs), being build around Nippon caps (I made full cap list for myself, that you can see below as well). However, the bulk caps may be bit bulgy, or it is just me since their tops are covered in black. Do you think it is a good idea to do the full recap? Also, how do you find the quality of this PSU, based on photos? Moreover, the max power of this PSU is 100 W and I am planning to use in this computer, Voodoo 1 as well as AWE64 Gold. There will be only one HDD and one optical drive. I have already ran such configuration and the reading on the wall was c.a. 65W. Do you think that it is safe to run so much stuff on this 100 W PSU?

That's proprietary bullshit, most likely only for a dedicated type of machine.
Don't invest anything in it.

Moreover that's one of the weakest PSU's I have ever seen, maybe for one harddisk and a floppy drive only 😁

EDIT:
That was maybe too harsh 😁
Keep that PSU, most likely your Olivetti only works with that one.

CoffeeOne wrote on 2020-03-24, 22:02:

That's proprietary bullshit, most likely only for a dedicated type of machine. Don't invest anything in it. […]
Show full quote

LuckyPiquel wrote on 2020-03-24, 21:27:

Using the occasion I want to consult everyone on one more PSU. This particular one comes from my "new" M24 Olivetti, that sports […]
Show full quote

Using the occasion I want to consult everyone on one more PSU. This particular one comes from my "new" M24 Olivetti, that sports Pentium and has strange format (I believe LPX). Nonetheless, I was thinking about recapping it, since I am using this computer as my main Socket 7 rig. I opened it today to investigate internals, and share photos here (please see below). The PSU is by Minebea, that I believe was quite a decent company. Inside the PSU looks impressive (comparing to the two above PSUs), being build around Nippon caps (I made full cap list for myself, that you can see below as well). However, the bulk caps may be bit bulgy, or it is just me since their tops are covered in black. Do you think it is a good idea to do the full recap? Also, how do you find the quality of this PSU, based on photos? Moreover, the max power of this PSU is 100 W and I am planning to use in this computer, Voodoo 1 as well as AWE64 Gold. There will be only one HDD and one optical drive. I have already ran such configuration and the reading on the wall was c.a. 65W. Do you think that it is safe to run so much stuff on this 100 W PSU?

That's proprietary bullshit, most likely only for a dedicated type of machine.
Don't invest anything in it.

Moreover that's one of the weakest PSU's I have ever seen, maybe for one harddisk and a floppy drive only 😁

EDIT:
That was maybe too harsh 😁
Keep that PSU, most likely your Olivetti only works with that one.

Will surely keep it, since it cannot be easily replaced with anything of standard size. Moreover, it has this 3pin connector in addition to P8 and P9 power cables (I believe that I saw sth like this before in some IBM (?)). Anyhow, too much hussle to replace it. Thats why I was thinking to at least recap it.

That's a nice one, albeit a bit low on power. The insides look much like my Astec SA145, there's even that Astec branded chip inside, and same Nippon caps, so who knows if it's really Minebea...
Anyway, mine is built around 1994 and I've recapped it last year. I was surprised how good the 25 year old caps measured, in some cases the replacements actually had somewhat higher ESR, and I've used lowest ESR that you can find nowadays from Panasonic and Nichicon. I have more confidence in the PSU after the recap, and I'm keeping the old caps to maybe upgrade a junk PSU some day.