exxos's Atari, Amiga & retro forum

Ouch! :WTF: :cry: :sigh:

So, while I don't have a lot of Atari stuff on that I can progress right now, I've also been taking another look at the Amstrad 386 portable PSU again.

It has +5v, +12v, -12V and -24v outputs, and the machine was just not playing nicely, with the -24V line only delivering-17v.

So I decided a recap is in order, and spent a little time documenting values and positions on the board. For larger caps, I like to write a number on the top of the cap with a Sharpie, then as I remove it I can assign a value to the number.

The caps looked fine, but as we all know, they are also good liars, so I set about removing them. The PSU is a Rubycon device, made in Japan, though still a good 30 years old!


On removal of the caps, this was the sight that greeted me:


Lots of gunge from capacitors that looked just fine. For a laugh I decided to run them through my tester, and out of 13 capacitors, only 2 came within 10% of their specced value and one came back with an ESR of 25 ohms. As you can see from the area circled in red on the next pic, they even dribbled on my tester!!


Board is cleaned, just need to get the capacitors ordered and installed and we'll see what the end result is.

Well, my Amsturd ALT386 is reassembled at last, it was a worry that the cat would find the bag of screws and disperse them randomly around the house, but that can't happen now :)

The PSU is recapped and providing the right amount of power now, though still not booting, however I do at least have a beep code from the damn thing, one, four, two, which is a parity error. Oh well, on to the next phase of investigation.

Just wondering if anybody has any experience of trying to bridge the localtalk/RS-422 network to ethernet? I suppose I should really finish my NetUSBEE, but this seems interesting since I also have some old Macs with the same port.

rubber_jonnie wrote: 19 Jun 2020 14:15 I suppose I should really finish my NetUSBEE, but this seems interesting since I also have some old Macs with the same port.

Jon, sounds like your netusbee is being built. How about some pictures.

Other than a Mac SE/30 running System 7.5 and the LocalTalk Bridge?

Earlier this year I had a Mac Plus accessing a drive on a Raspberry Pi via LocalTalk -> SE/30 -> EtherTalk -> Netatalk (Raspberry Pi).

Note: The Netatalk printer server is terminally broken. I was at the time looking if I could port the CAP60 lwsrv8 server to use the Netatalk libraries.

P.S. Have a look at this: https://youtu.be/MV_xDpYq1fM The "macprint" server is actually the Raspberry Pi next to the Mac Plus.

stephen_usher wrote: 19 Jun 2020 15:24 Other than a Mac SE/30 running System 7.5 and the LocalTalk Bridge?

Earlier this year I had a Mac Plus accessing a drive on a Raspberry Pi via LocalTalk -> SE/30 -> EtherTalk -> Netatalk (Raspberry Pi).

Note: The Netatalk printer server is terminally broken. I was at the time looking if I could port the CAP60 lwsrv8 server to use the Netatalk libraries.

P.S. Have a look at this: https://youtu.be/MV_xDpYq1fM The "macprint" server is actually the Raspberry Pi next to the Mac Plus.

Cool thanks, I'll have a look.

PaulJ wrote: 19 Jun 2020 14:24

rubber_jonnie wrote: 19 Jun 2020 14:15 I suppose I should really finish my NetUSBEE, but this seems interesting since I also have some old Macs with the same port.

Jon, sounds like your netusbee is being built. How about some pictures.

Being built is a bit of a stretch.....

I should really get on with it, better drag it out and crack on!

Ya, I still have the bare board but the netusbee is really a pig in the poke. Works great in some machines and stops others from booting. :headbang: :headbang: :headbang:

PaulJ wrote: 19 Jun 2020 16:42 Ya, I still have the bare board but the netusbee is really a pig in the poke. Works great in some machines and stops others from booting. :headbang: :headbang: :headbang:

I'm a little further ahead then....

I should probably put it under the microscope and check for shorts!!