exxos's Atari, Amiga & retro forum

If you're going to do a full desolder you might as well put a socket in there.

stephen_usher wrote: 01 Apr 2022 09:44 If you're going to do a full desolder you might as well put a socket in there.

Yeah I will, though I need to see if I have something suitable first. There's plenty of room above the mainboard so no problems having a socket there.

From what I can see the only reason for having such a vast case is either to allow for a mechanical keyboard and/or convection cooling.

I think it was mostly that the motherboard + power board are large and having the mechanical keyboard, forcing the height. Otherwise it's just a mildly styled box. The large internal space is just a by-product.

stephen_usher wrote: 01 Apr 2022 10:03 I think it was mostly that the motherboard + power board are large and having the mechanical keyboard, forcing the height. Otherwise it's just a mildly styled box. The large internal space is just a by-product.

TBH the mainboard isn't that big, it's a smidge smaller than the one in my Toshiba HX-20. The power board is huge though, as wide as the mobo, and half as deep with a huge heatsink:


It's just slightly smaller than the Apple ][e, though I have to say, it is smaller than I remember. This is possibly the last machine I need to collect from my childhood, with the exception of a TRS-80 perhaps.

Well, it's ALMOST a TRS-80 CoCo. :-)

stephen_usher wrote: 01 Apr 2022 10:27 Well, it's ALMOST a TRS-80 CoCo. :-)

I know, so close, but it's one of these I really want:

Tried a quick lunchtime reflow of the obviously bad pins, but still no keyboard action.

However, I did notice I have a flashing cursor, which I don't recall before, so thinking that the machine is actually working 😁

So, full desolder of the 8261 and socketing later.

If you have issues, have a chat with @HereBeDragons3 on Twitter.

stephen_usher wrote: 01 Apr 2022 12:17 If you have issues, have a chat with @HereBeDragons3 on Twitter.

Cool, thanks 😁

Ok, so I suspect the M6821 PIA is not happy, however I made what seems to be a bit of a surprising discovery with the keyboard PCB.

This is just one of the key switches:


Now I'm feeling a bit dumb, I checked the switches worked ok, but almost entirely discarded the idea that the keyboard itself was bad on account of it being so simple. I thought this morning "Let's just give the keyboard the once over under the magnifier, make sure there's no track damage".

And I'm glad I did because all of the keys are in this state.

There are some that have only 1 failed joint, but the majority have both.

I see a major reflow exercise over the weekend, and I'll also remove the PIA and socket it too.

I've never seen this many bad solder joints in one place, it's quite astonishing, and does show that mechanical damage can easily contribute to problems in machines of this age.