exxos's Atari, Amiga & retro forum

The B+ 128K is OK other than the feet starting to turn to goo.

So, dismantling the Master's power supply it's not been fully recapped, just the X2 caps and the start-up cap, which hasn't been fitted very well.

I'll check my stock of caps. There are quite a few on the output stage. They're mostly 2200uF, 16V and 25V.

stephen_usher wrote: 08 Jan 2026 12:23 I also wanted to check the B+ 128K as that has a habit of Hitachi lower (4164) RAM chips failing when in storage, two have done so so far and had to be replaced.

I can relate as my 800XL has 4164's of which one has died after sitting for a while...

Well, that was "fun". (For certain values of "fun").

I recapped the BBC Master PSU, though I didn't have all the values I did have them for the +5V side. I pulled all the caps and the ones for the +12V (external power only) and -5V were OK-ish. On the 12V rail it had, for some reason, a 25V 2200uF cap (the +5V had three 2200uF 16V caps) which I didn't have in stock so I reused it.

I diligently soldered the caps in with the negative leg in the hole denoted by a white dot... (more about this later... forboding...)

Put everything back together and tested the voltages without it being in the machine... all fine, except the +12V was a little low.

So, I re-assembled the machine and turned on for a test.... after about 30 seconds there was a pop, sizzle and smoke. Quickly turned off at the wall.

Disassembled and found the cap on the 12V rail had gone pop. OK, I thought, it was obviously on the way out. It's on the 12V rail so a 16V cap should be fine, so fitted one of those.

Reassembled the PSU, tested, all seemed fine.

Reassembled the Beeb and powered up... 1 minute later... Pop! Darn!

So, disassembled everything again, and it was the new cap on the 12V rail... again.

It was at this point I looked at the photos I took before I removed the caps and.... the caps were all the other way around! Obviously the silk screen white dot denoted + and not -!

Anyway, it's back together again and it ran for a few minutes before I switched off to come in for a break.

The Master seems happy now. It's been running the Master enhanced version of Elite for 20 minutes and no smoke. :-)

:bravo:

The Master has been running for a couple of hours with Chuckie Egg so it's fine now, even with a couple of the older capacitors in it. I think I'll still order some though and finish the job later.

Oh. The A8PicoCart has just arrived.

stephen_usher wrote: 09 Jan 2026 12:07 Oh. The A8PicoCart has just arrived.

Time for some A8 fun then :)

Indeed!

I'm quite impressed how quick and easy to use it is. Of course, it shows how I could do with a RAM upgrade.

stephen_usher wrote: 09 Jan 2026 13:14 Indeed!

I'm quite impressed how quick and easy to use it is. Of course, it shows how I could do with a RAM upgrade.

Demo's was one reason I opted for U1MB as some required up to 1MB and a lot need 320KB and something like Rambo is only 256KB. Of course there's lots of upgrades out there I just prefer U1MB as you have the ability to configure all the way through from 64KB up to 1MB.

Of course it's not cheap, but it does allow for multiple profiles.