Does anyone have the ability to burn PROMs? I'm looking for the two main board PROMs and the ACI PROMs willing to pay. I have some blank D3621's I bought when I niavely though I could use a standard EEPROM programmer to burn them.https://www.ebay.com/itm/291067683069
The other option I guess is to build my own PROM burner and just write the data myself. Does anyone know what voltage is needed to pop these fuses? Thanks!
In post #1, DevinWatson wrote:
"The other option I guess is to build my own PROM burner and just write the data myself."
Uncle Bernie warns:
Sorry to shatter your illusions but building your own bipolar PROM programmer is no realistic option, even if you have the programming spec.
These nasty devices based on fuse links are extremely tricky to program, lots of current involved, the drivers must have controlled rise and fall times, and what's worse, when the fuse link opens you cannot allow any parasitic inductor to produce a "spark" in that newly formed spark gap.
All what you can achieve with your homebuilt programmer is a colossal waste of time and money, lots of damaged PROM blanks, and if you "succeed", bad reliability due to fuse growback.
I still have an overstock of 512x4 PROM blanks and it you want to pay the price for these then I can make you a set. Then you get my 'diagnostics' page to test your build and the 'extended format' page in the ACI PROMs as a free bonus. I don't charge anything for the software, you just pay for the blanks and the postage. Postage within the USA is OK ($5 at the moment) but postage to Europe is insanely expensive.
You can send me a PM (use the "Send PM" button) to learn more. This applies to anyone seeking Apple-1 PROMs. Oh, I do have the written permission from Woz to sell PROMs with his Apple-1 firmware, so there are no copyright issues.
- Uncle Bernie
Thanks for being a tour de force keeping the Apple I builder community up and running!