It's definitely not Intel, but I pulled the control board and traced it a bit this afternoon. It seems to be very similar to the circuit used on the Intel MP7-03 1702A programming module for the MCS-4/MCS-8 development systems.

On 10/30/21 7:35 PM, Jonathan Chapman via cctalk wrote: The colors aren't right for Intel, either. The scheme looks closer to that of the Zilog MCZ. --CHuck

It is possible that it is run from a switch box as I see 3 ea 9602 timer chips. That would be 1 for pulse on, one for pulse off and one for duration of pulses. My timing was wrong. The duration of pulses should be 120/256 = 0.47 seconds. This is based on the timing of programming in 2 minutes as specified. Dwight From: cctalk cctalk-bounces at classiccmp.org on behalf of dwight via cctalk cctalk at classiccmp.org Sent: Sunday, October 31, 2021 6:53 AM To: General Discussion: On-Topic and Off-Topic Posts cctalk at classiccmp.org Subject: Re: Mystery 1702A(?) EPROM Programmer I also agree, it looks like the MP7-03 with some I/O buffering. My guess is that the connector on the back is similar to the interface to the SIM4-01. There would be address, data and a strobe to do the programming. The way it works on the SIN4 setup is that the programmer supplies the timing for the pulses but the 4004 supplies the duration of the programming pulses. So the programming sequence would be to hold the programming active for about 79 milliseconds then delay long enough for pulses to stop before changing the address and data. This would be a simple Arduino program. Hopefully the programming signal is a low so that it would be in the read mode with nothing driving it. Do remember, the 1702A is a PMOS part and is a hard pull up and a weaker pull down, unlike TTL. Dwight From: cctalk cctalk-bounces at classiccmp.org on behalf of Jonathan Chapman via cctalk cctalk at classiccmp.org Sent: Saturday, October 30, 2021 8:03 PM To: Chuck Guzis cclist at sydex.com; General Discussion: On-Topic and Off-Topic Posts cctalk at classiccmp.org Subject: Re: Mystery 1702A(?) EPROM Programmer I assume the box is just a somewhat generic project enclosure, similar to standard offerings from Bud, Hammond, etc. I'll go through the power supply tomorrow or Monday and see where I can get with read mode. It looks like writes should be hardware timed, so that's good news! Thanks, Jonathan ??????? Original Message ??????? On Saturday, October 30th, 2021 at 22:52, Chuck Guzis via cctalk cctalk at classiccmp.org wrote: > On 10/30/21 7:35 PM, Jonathan Chapman via cctalk wrote: > > > It's definitely not Intel, but I pulled the control board and traced it a bit this afternoon. It seems to be very similar to the circuit used on the Intel MP7-03 1702A programming module for the MCS-4/MCS-8 development systems. > > The colors aren't right for Intel, either. The scheme looks closer to > > that of the Zilog MCZ. > > --CHuck