As part of the 8870 documentation process, I thought it would be sensible to make copies of all EPROMS and ROMS contained within the hardware (system boards and terminals). Early 8870 hardware often had EPROMS and these can “fade” over time so it’s sensible to have images from known working devices stored safe and sound.
The first place I decided to start was with the EPROMS / ROMS stored in the DAP4 CPU board. However, and there’s always a however with Nixdorf hardware, the EPROMS are actually 2516’s and these use a different pin-out to standard 2716 devices and they also need 25v for the programming cycle; this means my old and trusty EPROM programmer won’t program them, and more of an issue, won’t read them either. I could make an adapter board to allow them to at least be read, but my friend VAXMAN mentioned that he had some 2708 EPROMS he would like to read and these devices are complete pigs to use; they need +5, -5, +12 and +25v and there’s no way my programmer will ever handle these. So I decided it’s time to design and build a new one. Whilst I’m at it, I’m taking the opportunity to build-in some additional features that I’ve always found missing. I want it to be able to handle just about any EPROM available, RAM chips, and be able to be used as a ROMULATOR (ROM Emulator).
Once it’s done, I’ll post the design, PCB foils etc. here for those that are interested. I may even build you one if you ask nicely!!
I’m still hunting around for a NIROS operating system but so far, I’ve not had much luck. I have been in contact with somebody who has a rather large Nixdorf 8870 collection but most of his equipment isn’t currently running and I’ve offered my services to help him get things going. Perhaps we can salvage an op-sys off one of his systems.
The first place I decided to start was with the EPROMS / ROMS stored in the DAP4 CPU board. However, and there’s always a however with Nixdorf hardware, the EPROMS are actually 2516’s and these use a different pin-out to standard 2716 devices and they also need 25v for the programming cycle; this means my old and trusty EPROM programmer won’t program them, and more of an issue, won’t read them either. I could make an adapter board to allow them to at least be read, but my friend VAXMAN mentioned that he had some 2708 EPROMS he would like to read and these devices are complete pigs to use; they need +5, -5, +12 and +25v and there’s no way my programmer will ever handle these. So I decided it’s time to design and build a new one. Whilst I’m at it, I’m taking the opportunity to build-in some additional features that I’ve always found missing. I want it to be able to handle just about any EPROM available, RAM chips, and be able to be used as a ROMULATOR (ROM Emulator).
Once it’s done, I’ll post the design, PCB foils etc. here for those that are interested. I may even build you one if you ask nicely!!
I’m still hunting around for a NIROS operating system but so far, I’ve not had much luck. I have been in contact with somebody who has a rather large Nixdorf 8870 collection but most of his equipment isn’t currently running and I’ve offered my services to help him get things going. Perhaps we can salvage an op-sys off one of his systems.
DAP4 being eatern by a leaking lithium battery.
This reminds me… those of you who are holding onto old equipment, Nixdorf, DEC, IBM, whatever, please.. PLEASE make sure that you check terminals for batteries (rechargeable or lithium) and any battery backup systems contained within your main chassis. These batteries leak and do terrible damage if left unchecked. Go on… go check now, you may be just in time to stop one of your system boards being eaten.
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