On the plus side the front panel seems functional (except for one LED). I can at least examine and deposit data.
Well, the old Gifford computer is doing something. I have blinking lights, but she is not loading anything from the drives. I will have to check what is on the EPROMS. In the notes I have it only talks about loading from tape. Also nothing shows up on the terminal screen. On the plus side the front panel seems functional (except for one LED). I can at least examine and deposit data.
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Just about ready to fire this baby (Gifford S-100) up. Any bets as to whether or not she starts first time?
Stay tuned tomorrow to see what happens... My Commodore PC10-III was having trouble booting from the floppy drives. However, it exhibited the following behaviours:
After lots of troubleshooting, it turned out to be a very subtle thing indeed. The use of a 74LS04 chip instead of a 74S04 chip (near the RAM). Once I replaced that back to what was supposed to be used, it booted correctly.
Got my Model III up and running after a keyboard rehabilitation and some cleaning of the disk drives.
At first the the disk drive to keep on spinning after issuing a DOS command like DIR. Eventually the problem seemed to just go away. The keyboard was pretty flaky. I had to more or less clean or re-paint the conductive pads on most of the keys. What a pain. Today I managed to get a hold of the service manual for the Wyse WY60? The video was over-scanned or something as it is upside-down and distorted. That manual helped me narrow down the hunt for a bad cap. It was a tiny one too, which I missed the first time around I was hunting around in there. Once it was repaired, the monitor worked perfectly. Now all I need to do is find a matching keyboard.
Just as I thought I was on my way to MFM happiness, I found that my ST-225 has other problem. It seems to indicate that there are defects in every spot on the drive, which cannot be correct. Other tests passed (Controller test, seek tests etc.). This was very odd. Even the second MFM drive failed as well. This time it turned out to be a hardware issue. Upon close inspection of the controller, I noticed that a capacitor leg was broken off near where the data cable connectors are. Once it was replaced, the card initializes (i.e., low level formats) the disks just fine.
Tried this (unknown WD) card out with two MFM drives (a Seagate ST-225 and a Priam ID130-AT-D2) in my IBM5170. No matter which address I use in Debug (i.e., G=C800:5, G=CA00:5, G=CC00:5 or G=CE00:5) to initiate a low level format it just seems to hang. I can restart the computer with a CTRL-ALT-DEL, so the computer isn't seriously hung. The floppy portion of the card seems to function correctly. A few months ago I had tried this card out in a Pentium MMX machine and had the same issue, but at the time I thought it might have had a conflict with the onboard IDE controller. For the longest time, I thought that this card was either:
It turned out that this particular card has no onboard ROM, so executing onboard anything in Debug, is not going to do much. This card requires a floppy based program (such as SpeedStor) to low level formatting. That was a new one for me.
Got this yesterday (along with 4 others) in a lot of stuff I bought. Fresh out of the box, never been used. Even the plastic film was still over the screen when I opened the box up. This baby will work perfectly for a few projects I have.
I have scanned the User's Manual for anyone that is interested. Bull electro-mechanical keyboard. This puppy is a bit more than just vintage. When I came across it, I had no idea what it was from, or how old it was, but I suspect it goes back to the days before micro-computing. It looks like it is from the 1950s at least. It is from a punch card key punch machine similar to an IBM 526 or 26.
It has quite the complex looking connector, but I was able to find a mating one from Digikey. This should be interesting to play with. |
AuthorCharles Baetsen holds a Bachelor and a Master's degree in Engineering Physics from McMaster University in Hamilton, Canada. Archives
February 2024
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