glitch
Veteran Member
While cleaning out part of our warehouse at work, I found two Cromemco Z-2 rackmount chassis enclosures, one with the original Cromemco S-100 motherboard, and one with a Thinker Toys Wunderbuss motherboard. One of the cases had the ZPU card and an Ithaca Intersystems 64K dynamic RAM board. Neither case has a functional power supply (blown rectifiers and bad caps in one, just bad caps in the other). Since the Wunderbuss is small enough to work on at my workstation, and set aside at the end of the day, I've been working with it, using a triple-voltage bench supply.
So far, I've repaired the Wunderbuss to the point that I'm getting the correct voltages on the S-100 connectors (bad tantalum caps...) and regulated voltage on the spade connectors (presumably for drives?). I plugged the ZPU card in last week, and its regulators put the right voltages onto the Z80's socket pins. The oscillator produces the correct frequency at the crystal. Someone had scavenged TTL chips from the ZPU, so I spent the weekend pulling them from other board I've got. The ZPU will get another firing-up Monday at work, to see if the oscillator signal reaches the Z80.
I'm not sure as what to do for the next step, though. I purchased a 4FDC card, which is reported to be working, in order to test the system. Does the 4FDC require a RAM board to be installed to get anything from the console? Its manual suggests that RDOS does use a portion of RAM for a stack. The Ithaca board is questionable, as it has several board-level modifications, and the 5 volt regulator has been replaced (I think this is a result of the failure of the power caps in the chassis it was installed in).
Any suggestions or pointers?
So far, I've repaired the Wunderbuss to the point that I'm getting the correct voltages on the S-100 connectors (bad tantalum caps...) and regulated voltage on the spade connectors (presumably for drives?). I plugged the ZPU card in last week, and its regulators put the right voltages onto the Z80's socket pins. The oscillator produces the correct frequency at the crystal. Someone had scavenged TTL chips from the ZPU, so I spent the weekend pulling them from other board I've got. The ZPU will get another firing-up Monday at work, to see if the oscillator signal reaches the Z80.
I'm not sure as what to do for the next step, though. I purchased a 4FDC card, which is reported to be working, in order to test the system. Does the 4FDC require a RAM board to be installed to get anything from the console? Its manual suggests that RDOS does use a portion of RAM for a stack. The Ithaca board is questionable, as it has several board-level modifications, and the 5 volt regulator has been replaced (I think this is a result of the failure of the power caps in the chassis it was installed in).
Any suggestions or pointers?