---snip--- the lower left, 7400 chip I think. Someone has socketed every chip on the board, with a collection of random colorful sockets. The board shows some small rework with kynar, to fix lost pads/traces on one socket pattern. Needs a couple of switches replaced. Marked "3421K" in black Sharpie. Get a schematic and start plaing with it. Like the IMSAI panel, it uses the processor to actually generate the addresses and fetching from the bus. You should check for shorts with an ohm meter before powering up. After powering up, check for anything that is hot. These old TTL parts would run slightly warm but should not be hot. Be ready to remove the power quickly in case of smoke. With power applied, even FR4 will burn if sustained with an electrical arc. There is a schematic and layout on that CD ROM that has many of the schematics and such ( I've seen but don't have it my self ). has been added with glue & kynar), and CPU is missing. Marked "3423K" in black Sharpie. The extra chip is most likely to generate the correct status signals for the refresh of the dynamic RAM. The early boards were designed around static RAM systems and it wasn't until later that the status signals were added. The earlier DRAM boards had no standard way of providing these signals so there are several different ways this was done. ---snip--- List major IC's? Will most likely only work with the Z80 processor board. The 8080 was a little on the slow side to handle the disk transfers. Most 8080 systems used a DMA interface for disk drives. I did look at some tricky software that I believe would have worked on a 8080 but it required transfering 4 bytes at a time. It has been some time since I looked at doing that so I'm not much help now. I think the main thing was that after the controller gave the status, you had something like 13 uSec to read the data or it was lost. fully populated. No idea what the capacity is) It depends on which chips are there. If it has the four banks of 16K chips, you have 64K. It could also be populated with 18K or 4K chips but that is unlikely as it came out just when the 16K chips were getting available. See my note above about the refresh signals. matching Z-80 buss driver chip. Has 4 ROM sockets, two of which are populated. One is clearly marked 'EDO BIOS'. Also has edge connectors marked serial & parallel I/O. Seems like a multifunction card; CPU, ROM & I/O) This is most likely the main processor that was used with the system for CP/M. emulator probe, bearing an EPROM chip. (It's clearly an In-Circuit Emulator device, my guess is that it was emulating an 8048 or similar) Most likely correct here. and flying components. I wouldn't let this thing near a running system. (seems like a generic breadboard card, which has been built into some form of custom hardware, has a large device marked "Analog Devices 940", and about 12 other chips, plus a pile of discete components) I believe the 940 is an amplifier module but I'm not sure. It could be a voltage converter as well. They made many discrete circuit instrument amplifiers that had especially low offset inputs. I would get this was an analog board of some type. ---snip--- It looks like a good project. Later Dwight