General Stuff(tm)

[stephen_usher]

This evening I tried to see if there was any way of adjusting the brightness on the CRT board of the second Kaypro. It turns out that the Dotronix board has no adjustment for the brightness at all!

So, I thought I'd see if I could get composite video out, so probed the output pins on the main PCB... H-sync, v-sync and data.

Just as a thought, I probed the 74LS00 next to the pins and yes, that was processing the signal but... just a mo, the output for the data was only 2.5V peak to peak and this is a TTL chip so should be outputting 5V. The chip was socketed (I wonder if it was a common failure point) so I swapped in a new chip and the data line went up to 5V. Plugged in the monitor cable in and...

IMG_3651.jpeg

A very usable, though still not super bright, display!

[PhilC]

And no high voltage electrocution occurred , well done.

[rubber_jonnie]

Woo hoo 😁

[stephen_usher]

I haz deliveries!

The BlueSCSI V2, 68882 and FDC9216B have arrived, so I can get on with things.

The first and quick one will be swapping out the floppy data/clock separator chip, as the machine's already on the bench, and seeing if it can now read floppies. I can also quickly open up the LC III and throw the 68882 and BlueSCSI into the machine as I've already printed a mount for the drive. I can work on the hard drive image(s) later.

[rubber_jonnie]

I haz deliveries!

The BlueSCSI V2, 68882 and FDC9216B have arrived, so I can get on with things.

The first and quick one will be swapping out the floppy data/clock separator chip, as the machine's already on the bench, and seeing if it can now read floppies. I can also quickly open up the LC III and throw the 68882 and BlueSCSI into the machine as I've already printed a mount for the drive. I can work on the hard drive image(s) later.

I do like the BlueSCSI, makes it so easy to get different HDD images for machines, and makes backing them up a breeze :)

[stephen_usher]

Replaced the FDC9216B and the Kaypro can read disks again.

[PhilC]

Replaced the FDC9216B and the Kaypro can read disks again.

:cheer: :cheer: :cheer:

[stephen_usher]

Completed the refurb of the second Kaypro today.

Drive B wasn't spinning to I bit the bullet and got it out. This involved getting a screwdriver in through the far side of the machine, underneath the tube to loosen one of the screws. It also meant drilling the heads off the two pop rivets whoever had replaced the drives had used to fit his own blanking plate between them.

Anyway, I got it out and the spindle would hardly move. Removing three small screws on the lower plate of the spindle allowed me to remove it to find that the bottom edge of the magnet had fallen off and was fouling the motor PCB. The bearing was also very dry but I couldn't get to that so tried flooding the area with oil, which seemed to loosen things up a bit.

I re-attached the lower magnet part with superglue and reassembled. Thankfully it still worked.

I found some screws which would fit the blanking plate and the holes that the pop rivets used to be in so that was fitted back.

Anyway, it's all working. I managed to get a working floppy disk to boot from and proved that I could format another and duplicate the original CP/M disk. Drive B is still slightly squeaky but I can't do anything more to fix that.

So, here it is.

IMG_3656.jpeg

[rubber_jonnie]

Completed the refurb of the second Kaypro today.

Drive B wasn't spinning to I bit the bullet and got it out. This involved getting a screwdriver in through the far side of the machine, underneath the tube to loosen one of the screws. It also meant drilling the heads off the two pop rivets whoever had replaced the drives had used to fit his own blanking plate between them.

Anyway, I got it out and the spindle would hardly move. Removing three small screws on the lower plate of the spindle allowed me to remove it to find that the bottom edge of the magnet had fallen off and was fouling the motor PCB. The bearing was also very dry but I couldn't get to that so tried flooding the area with oil, which seemed to loosen things up a bit.

I re-attached the lower magnet part with superglue and reassembled. Thankfully it still worked.

I found some screws which would fit the blanking plate and the holes that the pop rivets used to be in so that was fitted back.

Anyway, it's all working. I managed to get a working floppy disk to boot from and proved that I could format another and duplicate the original CP/M disk. Drive B is still slightly squeaky but I can't do anything more to fix that.

So, here it is.


IMG_3656.jpeg

Excellent work, this one seems to have been the easier of the two to repair in the end.

[PhilC]

Well done @stephen_usher , those are definitely an interesting computer to add to your collection.