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You inspired my to drag my Explorer out of the box to power it up. Attached is a photo with the franken-RS-232 connection. It's just a FTDI connector with an inverter on the two data lines and then connected to the TTL side of the I/O. That gets all of the analog RS-232 stuff out of the way...

Just finished building mine. This is a really nice kit. The board well designed and is clearly marked so you can almost build it without the directions. I did run into one odd problem with the serial clock. The oscillator is putting a clean signal into the 74HCT4040 counter, but the output...

As an alternative to Willem programmers and the budget USB designs, I've put together a EPROM programmer that can be built on a breadboard using an Arduino and a few additional parts that you probably already have in your parts bin. It isn't meant for production use, but can be a handy way to...

My updates to the Arduino EPROM programmer for the 8755 worked. I'll create a post with the schematic and new code. The hardware design is simple. It has just needs two transistors and a few more components to switch the VPP voltage between 5V and 25V. It can program the whole chip in about...

Here are photos of the AP-1 Power Supply. I'll get the manual scanned and will post that as well.

This isn't really an S-100 computer, but it was inspired by one, so this seems like a reasonable forum for it. I recently dug out my old Netronics Explorer/85 from 1981 and powered it up to see if it still worked. After a little re-soldering and some creative RS-232 solutions, it booted up...

Those are the Basic ROMs. Two new photos are attached that show things a little clearer. Thanks for the link. I have those same manuals, same versions, although not scanned in. I should probably have the Basic manual under glass. It was probably stapled by Bill Gates himself. I originally...

falter, I just took another look at your photos and realize what you meant by ikbd. You are correct - that is the ROM monitor burned into an 8755. Mine is in the factory-programmed 8355 instead. I'll post a pic so we can compare boards. Yours has the connector for the keypad next to the...