E-mu Emulator Sampler User Forum for the EIII EII EI and EIII XP - EIII - PAL Chips on the CPU Board

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Author Topic: EIII - PAL Chips on the CPU Board  (Read 78 times)
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Posts: 6

« on: December 31, 2017, 01:19:46 AM »


I got some issues with the PAL-Chips on the CPU-Board of a EIII Keyboard 4MB. During a repair session I realized that 3 of the 4 existing PAL-Chips on the CPU Board are forever gone. So I tried to find the neccessary programming informations, the JEDEC Files, that describe the internal behaviour of that Programmable Logic Devices and that are needed to create spare parts.

Unfortunately I only found one JEDEC File in this forum describing the internals of IC27. The others are missing.

- IC 27 (Type 16L8, Chip Select PAL internal number IP374) --> JEDEC available in this forum
- IC 10 (Type 16L8, Interrupt/Wait PAL with number IP373) --> JEDEC missing
- IC 11 (Type 16R4, UPRAM PAL with number IP365)           --> JEDEC missing
- IC 32 (Type 16R4, Serial PAL with number IP366)             --> JEDEC missing

After a little investigation and reading much threads in this forum I am still not sure about following :

- Are the used PAL Chips protected, or not ?

If they are not protected :
- They could be read out and copied. You only need a working Chip, a appropriate reader,
  and some knowledge about recompiling the PAL content for the spare IC.

If they are protected : 
- They could not be read out and copied directly.
- At my state of knowledge only a "brute-force approach" could work for IC27 and IC10   
  (because they are combinatorial). This takes much more time and need special equipment.
- At my state of knowledge IC11 and IC32 can't be copied in any way (because they are registered).

Hopefully I'm wrong, ...  and someone comes up with all the needed JEDEC files.
So I request the help and the knowledge of the community to clear this topic.

Thank you very much

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E-mu Emulator Sampler User Forum for the EIII EII EI and EIII XP - EIII - PAL Chips on the CPU Board

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