My latest restoration in pictures

General discussions or ideas about hardware.
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exxos
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Re: My latest restoration in pictures

Post by exxos » Mon Jul 16, 2018 8:20 pm

tzok wrote:
Mon Jul 16, 2018 8:08 pm
Caps in ST are not known to cause problems or being excessively faulty.
That is simply not true, I documented it like 10+ years ago that PSU's were failing in STEs. I even documented why on my site. Bad caps. I've had like 200 PSU's through my workshop, none of which will power a STE with 4MB RAM (but mostly work OK with 512K) . SR98's are ( in my book) the ones which typically fail first. Re-cap them, they work better than new. Some others like the DVEs tend to live a lot longer, though I have not seen more than about 20, so not a huge sample range to try.
tzok wrote:
Mon Jul 16, 2018 8:08 pm
I've recently noticed, that everyone is recapping a vintage computers. They seem to see a remedy for all faults in it.
Old caps indeed can go bad. But also I've worked for a company repairing volumes of switchmodes. Was lucky to get 3-6months out of caps in the things.

One of the big gaming companies purchased a large number of ABIT motherboards, and at the time I always used to use them as liked their products. I remember ABIT refusing to replace all the motherboards under warranty as all the caps kept blowing up in under 3 months. I'm talking like millions of motherboards not just not few.

Similar with several large manufacturers of power supplies used to deal with. The amount of capacitors we had to change was unbelievable. They would hardly ever get past 6 months use. Of course a lot of it was bad circuit design, bad implementation etc. ST PSU's have done remarkably well compared to all the more modern power supplies which I was seeing my old job.

My point being that simply age of the capacitor is only part of the story. How it is used and of course quality of components is also a factor. It can actually get pretty complicated.
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxoshost.co.uk/atari/last/storenew/ - All my hardware mods for sale - Please help support by making a purchase.

stephen_usher
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Re: My latest restoration in pictures

Post by stephen_usher » Mon Jul 16, 2018 8:43 pm

A lot of the problems with many PCs 10-15 years ago was due to an electrolyte manufacturer in Japan producing a duff product which was then used by practically all the capacitor manufacturers at the time. Basically everything from that period either died within months or at most a few years.

We had whole generations of Dells (servers and desktops) all go at the same time, all with popped caps.
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.

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exxos
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Re: My latest restoration in pictures

Post by exxos » Mon Jul 16, 2018 9:05 pm

Think this was all going on early 2000. Thought the bad cap thing was earlier than that, more like early 90s ? Never looked into it.

EDIT:
Oh found it... https://en.wikipedia.org/wiki/Capacitor_plague

Probably explains what I saw in my old job then.
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxoshost.co.uk/atari/last/storenew/ - All my hardware mods for sale - Please help support by making a purchase.

mikro
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Re: My latest restoration in pictures

Post by mikro » Tue Jul 17, 2018 7:27 pm

tzok wrote:
Mon Jul 16, 2018 8:08 pm
My opinion is to not replace anything that still works good. Caps in ST are not known to cause problems or being excessively faulty. There were a series of faulty caps in other home computers from '80s and '90s, but not in ST.
This is a photo of an Atari PSU right before recapping. Fully functional PSU...
IMG_20180630_120334.jpg
IMG_20180630_120334.jpg (143.92 KiB) Viewed 342 times

tzok
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Re: My latest restoration in pictures

Post by tzok » Mon Aug 27, 2018 7:32 pm

...and? The stains are probably residues of electro-isolating lacquer the PCB was painted with. They are visible around all components.

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