exxos's Atari, Amiga & retro forum

Bought a new RJ10 cable for the keyboard on the Kaypro in case that was the reason it wasn't working... but it's obviously not wired correctly as a straight through. *sigh*

So, new plugs and a crimping tool ordered from Amazon for tomorrow.

Got one of the drives on the Kaypro working again. A LOT more lubrication of the stepper motor bearings. Flooded it a bit and left it to soak overnight.

On the railway front tried the grout. It turns out I got black rather than charcoal, so it's a bit too dark even for new asphalt. Also learnt some useful lessons. It's a good thing that this is just a test platform.

It looks like there's no post delivery at work today so no Z80 SIO chips.

stephen_usher wrote: 14 Feb 2024 14:13 It looks like there's no post delivery at work today so no Z80 SIO chips.

:pullhair: :pullhair: :pullhair:

Well, soaking the stepper motor bearings in oil seems to have done the trick and the "Drive B" TM100-2A drive is working fine still.

Had an issue with booting up where the machine would crash oddly. Reseated the Z80 and it was happy again. I'm really not happy with the single-wipe sockets, especially with the amount of tarnish on the chip pins from being stored essentially outside for 25 years. Still, I don't want to desolder anything if I don't have to as that's even more dangerous.

@stephen_usher if you have some female pin headers then put the Z80 in to that and then in to the single wipe sockets. It’ll make a much better contact and will save you having to replace the socket immediately to do the diagnostics

stephen_usher wrote: 14 Feb 2024 20:12 Well, soaking the stepper motor bearings in oil seems to have done the trick and the "Drive B" TM100-2A drive is working fine still.

Had an issue with booting up where the machine would crash oddly. Reseated the Z80 and it was happy again. I'm really not happy with the single-wipe sockets, especially with the amount of tarnish on the chip pins from being stored essentially outside for 25 years. Still, I don't want to desolder anything if I don't have to as that's even more dangerous.

Good news re the steppers, nice one.

As for the single wipe sockets, they caused me on end of problems on my Apple IIe until I bit the bullet and replaced them, however to be careful round the traces I removed the plastic cage carefully from the top and removed each wipe one at a time to avoid damage to the traces. Might be a way to do it.

The post has arrived and no SIO chips.

Given that the seller used 2nd class post I wonder if they'll ever arrive.

P.S. Ordered a proper SIO-0 from Little Diode on eBay.

stephen_usher wrote: 15 Feb 2024 13:30 The post has arrived and no SIO chips.

Given that the seller used 2nd class post I wonder if they'll ever arrive.

P.S. Ordered a proper SIO-0 from Little Diode on eBay.

Rubbish :(

Although I can't do any more electronic work on the Kaypro (other than testing the "Drive A", more later...) I can do some of the hardware things.

I've ordered some UNC 4-40 machine screws which match the threads on the keyboard clips (which allow the keyboard to be clipped to the rest of the system for carriage) as one of the clips and its screws are missing. There's also one of the conical feet missing too, but I can use a 3.5" hard drive screw for that.

So, this evening I designed and printed replacement parts...


My recreations on the left and the originals on the right. I should really use TPU for the foot but I don't have a reel of that plastic.

As hinted earlier I've also looked at the "Drive A" issue with not reading disks. By manually pushing the head a little I can get data to show up on test points 1 and 2 on the drive, which shows that the heads and that part of the circuit is fine, with the correct 200mV amplitude, so it looks like the drive is either fully out of alignment or the track zero switch needs adjusting. I'm guessing the latter, but I'll look into this further later.