OSI 600D Superboard Build

[stephen_usher]

Looks pretty retro to me.


medium_cd0246_012_061019_2006_34_Nascom_1_home_computer.jpg

Nice Is that a UK 101?

Not quite, a Nascom 1, but from the same time period so they look similar.

[rubber_jonnie]

Nice Is that a UK 101?

Not quite, a Nascom 1, but from the same time period so they look similar.

Ahh, good old Nascom

[rubber_jonnie]

So, capacitors are completed now too

Kicking myself though, I ordered some solder mounted fuse holders that are taking an age to arrive, and whilst looking for something else in a drawer, I find a dead PSU. What does it have? A solder in fuse holder.

D'oh!

[PhilC]

So, capacitors are completed now too

Kicking myself though, I ordered some solder mounted fuse holders that are taking an age to arrive, and whilst looking for something else in a drawer, I find a dead PSU. What does it have? A solder in fuse holder.

D'oh!

I’m sure a wise man once said “it’s always good to have spares.”

[rubber_jonnie]

So, capacitors are completed now too

Kicking myself though, I ordered some solder mounted fuse holders that are taking an age to arrive, and whilst looking for something else in a drawer, I find a dead PSU. What does it have? A solder in fuse holder.

D'oh!

I’m sure a wise man once said “it’s always good to have spares.”

A wise man indeed

[rubber_jonnie]

Well, training was cancelled tonight so when I got home I got right into it with the OSI, and here's where it's at now:

PXL_20240111_211936876.jpg (409.87 KiB) Viewed 915 times

So I'm very pleased with the progress.

All that's left now are 16 missing resistors, which are all on order, which I'll be able to get installed pretty quickly, and then I can start getting the IC's sorted. Well, more sorted, they're part way done.

I'm going to leave the keycaps off until the very end, as I don't want to get them too scuffed up before the thing is completed.

It's a shame I couldn't have built one of these in 1979/80 (The date of my replica PCB), but the price for the UK-101 was just too expensive, and given my primordial soldering skills back then, I don't think my parents would have been happy to shell out £219+vat , and happily I got a ZX81 not long after.

The last thing I did was a small blob of hot glue under the electrolytics to be sure they don't move around, and can't short out.

Don't you love time travel

[stephen_usher]

Yeah, the UK101 was way out of my family's price bracket. Even the ZX81, which I got for Christmas 1981, stretched the budget, over a week's wages. (Of course, the price went down soon after.)

The RAM pack was my birthday present in the February.

[rubber_jonnie]

Yeah, the UK101 was way out of my family's price bracket. Even the ZX81, which I got for Christmas 1981, stretched the budget, over a week's wages. (Of course, the price went down soon after.)

The RAM pack was my birthday present in the February.

A very similar story to me then. I think the ZX81 was £69.99 assembled, which was a stretch for us at the time, and I had to save up to get a 16K RAM pack for it. I eventually soldered it directly to the ZX81 as it wobbled more than it didn't.

[rubber_jonnie]

Minor resistor update - some turned up today and I installed them

Fingers crossed the rest will arrive on Monday and then I can finish off the board and start the tests prior to inserting the ICs and working out what's missing in that department.

My ROMs are on their way, and are now in country, so fingers crossed for those next week too, which just leaves the RAM, which is in the post too, so lots of waiting for the postie.

However, the power up tests in the build manual do state to run the first tests with just 2 RAM ICs (They are 4 bits each, so only 2 required for a minimum config) and I have managed to get two from eBay, so even if the main order is delayed (I had to get them from Ali Express), I have enough to do the basic testing.

I've also talked myself into getting a 610 board which adds 24K of RAM and with another small board, an FDD interface. I must be mad.

[stephen_usher]

We're all mad you know.