Comments for page: 1702A EPROM Programmer

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Posted by Steve L. March 06, 2019 - 06:48 am
Hi MBu, Thank you for your post and for the kind comments. It's nice to hear that you're restoring the vintage printer. While I didn't see the pdf at the link (probably overlooked it), a web search brought up info on the DZM 180. Although the page it brought up is in Polish, it lists a date range (Daty skrajne) of 1970-1990. If that's the period of manufacture, it had a remarkably long life!

Posted by MBu March 06, 2019 - 06:56 am
@Va3qe: I had a similar problem as yours. The led went on as soon as I placed the chip in the read socket. It turned out that the card I used for LPT2 was not supporting the bidirectional mode. Finally I had to reconfigure the add-on card as LPT1 and the motherboard port was set to LPT2.
@Steve: Thanks for this great project! Yesterday I managed to program two EPROMS with character matrices for DZM 180 dot-matrix printer (a pdf with english description of this printer is available at

Posted by Matthew Millman February 18, 2019 - 04:23 am
That was about all I'd noticed too. So likely a 1702A "compatible" device, albeit manufactured with a newer process.

Based on those specs I cannot see any problem plugging it into my programmer!

Posted by Steve L. February 17, 2019 - 05:06 pm
Thanks Matthew, it's kind of you to make the project files available to everyone.

Regarding the 8702A versus the 1702A, I don't know much about that. I noticed back in the day that Intel had renumbered versions of the 1702A and other chips which worked with their 80XX microprocessors and I always assumed it was a marketing move to unify those product lines or perhaps that the peripheral chip specs were being tweaked to make them more appropriate for the processors. A 1975 datasheet for the 1702A shows its access time as 1us, whereas a 1975 datasheet for the 8702A shows access time as 1.3us. However, the 1702A-6 was also available, specified at 1.5us and the 1702A-2 was 0.65us.

Looking at the programming specs, the only significant difference I see is the 1702A typical Vbb supply current is 10mA but the 8702A is 0.05mA. The 1702A also has a note that Vbb must be limited to 100mA to prevent damage but the 8702A has no such note. The only current limiting I included was for Vdd at 300mA, which is specified for both part numbers.

If you find out more about the differences, please let us know.

Posted by Matthew Millman February 17, 2019 - 03:35 pm
You can do whatever you like with the images. It's going to be a completely open project i.e. gerbers, design files and source code will go up on github once I've cleaned it up, and written some documentation for it.

Actually it doesn't even need that serial port. It can use the Arduino's onboard serial-to-usb if desired (but cannot power its self from the USB).

Question for yourself: What's the deal with the 8702A? Is it a drop in replacement for the 1702A? different in some way perhaps?

Posted by Steve L. February 17, 2019 - 09:00 am
Hi Matthew, Thank you so much for your kind comments and for posting about your new, 1702A programmer project. I will add coverage of it to the survey section as soon as I can complete some much-needed infrastructure work on Can I have your permission to include the photo and schematic in that?

Your project is amazingly compact with the attached Arduino, yet includes on-board generation of all the pesky supply voltages and only requires a serial interface from the PC. That should make it popular indeed! I look forward to adding a link to your upcoming project page when it's available. I hope there will be a way for readers to obtain a board or more. Please keep us posted. Hearty congratulations for your impressive achievement!

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