exxos's Atari, Amiga & retro forum

rubber_jonnie wrote: 02 Dec 2024 18:25 Nice haul, I wouldn't mind an A500 as that's what I had BITD, not the 1200 I have now. I felt the 500 was a bit more special.

It's certainly larger and slower.

I stripped the A500 down this evening but before I did I ran Amiga Test Kit again (as a baseline test) and noticed that the 100KHz audio test wasn't working, so it looks like the board needs a recap. Of course, most of the values on the board I don't have in stock.

stephen_usher wrote: 02 Dec 2024 21:16

rubber_jonnie wrote: 02 Dec 2024 18:25 Nice haul, I wouldn't mind an A500 as that's what I had BITD, not the 1200 I have now. I felt the 500 was a bit more special.

It's certainly larger and slower.

I stripped the A500 down this evening but before I did I ran Amiga Test Kit again (as a baseline test) and noticed that the 100KHz audio test wasn't working, so it looks like the board needs a recap. Of course, most of the values on the board I don't have in stock.

Larger and slower for sure.

As for caps, it seems like no matter what I have in stock I never have the caps I need.

:dizzy:

rubber_jonnie wrote: 02 Dec 2024 18:25 Nice haul, I wouldn't mind an A500 as that's what I had BITD, not the 1200 I have now. I felt the 500 was a bit more special.

Well, @rubber_jonnie I seem to have more working A500s than I need, so I might be able reserve one for you if you'd like?

JezC wrote: 02 Dec 2024 21:46

rubber_jonnie wrote: 02 Dec 2024 18:25 Nice haul, I wouldn't mind an A500 as that's what I had BITD, not the 1200 I have now. I felt the 500 was a bit more special.

Well, @rubber_jonnie I seem to have more working A500s than I need, so I might be able reserve one for you if you'd like?

You'd better pm me then 😁

OK, so it's not the A500 having an issue with the 10KHz test, it's the A1200 generating harmonics I can hear. I've just tested with a FFT app on the iPhone and the 10KHz is there on the A500, I just can't hear that high any more. So no recap required.

Stage one of the memory upgrade complete: Sockets and bypass caps installed.


All checks out so far.


Just need the actual RAM chips to arrive now, which may take a few days.

Just noticed that eBay swapped my home address, which I'd explicitly used, for my old work address for the Amiga RAM. What a pain!

I've gone onto eBay and deleted all references to the work address now (I'd already removed it from PayPal) so it should never be able to pick that address up ever again.

stephen_usher wrote: 03 Dec 2024 18:47 Just noticed that eBay swapped my home address, which I'd explicitly used, for my old work address for the Amiga RAM. What a pain!

I've gone onto eBay and deleted all references to the work address now (I'd already removed it from PayPal) so it should never be able to pick that address up ever again.

I know that one. @Icky sent me a Phoenix mug, but it accidentally went to my old work address after we'd moved on when my boss sold the business. Luckily my boss was in the old building and reception said 'We have a parcel'.

So he took it, but then I didn't see him for a year, maybe more. I eventually got the mug and use it daily, but it took quite a while to arrive.

Well, at least you got the mug in the end!

Given that I'm not going to get the RAM chips for a little while I desoldered the ones from the trapdoor RAM card as chip RAM is more useful than slow RAM.

After fitting them I changed JP2 and low and behold I now have 1MB of CHIP RAM.

I didn't touch JP7A as looking at the schematics that only involves the clock pulse (EXTICK) and JP7B is set to use the sync pulse for that anyway, so there's absolutely no point in changing that. The guides on-line seem to have mistaken what that pint on the expansion port is for.

The one issue is that the sockets raise the height of the RAM high enough that there's slight interference with the metal shield and hence the keyboard, but as it's sub-millimetre it's acceptable as the keyboard does push into place with a small amount of force.

I'll fit sockets onto the RAM board so I can fit the new RAM when it arrives. I can then see if 512K of SLOW RAM appears in addition to the 1MB of CHIP RAM. If not it's no real loss.

rubber_jonnie wrote: 03 Dec 2024 23:59 So he took it, but then I didn't see him for a year, maybe more. I eventually got the mug and use it daily, but it took quite a while to arrive.

The wait was worth it though :)