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Found these inside a non-working 71B
03-14-2018, 04:20 PM
Post: #85
RE: Found these inside a non-working 71B
(03-13-2018 07:17 PM)J-F Garnier Wrote:  
(03-13-2018 06:19 PM)Paul Berger (Canada) Wrote:  Reading a little more about the memory configuration you could have a RAM module that contains more than 32K bytes the 64K nibble limit is for an individual chip but a module could contain more than one chip, ...
The HHP card reader RAM modules (made of 32K boards) can be configured to create a 64K port from two boards. See here for instance (the link to the file is dead, use this instead).
Unfortunately, it is not possible (or not known) to do the same with 32K CMT modules -well it should be possible since the CMT01 programmer does it.

BTW, I'm still interested by any information on the 1LQ4 chip. Somebody once said that a documentation exists but never shared.

I would be interested in actual documentation of the chip as well.

I will have to try that 64K mod I have a 128K module in pieces right now because the SRAM was bad on one of the boards, that is fixed now, at least I ran diags for about 18 hours and it did not find a problem. I was not so lucky my bad SRAM was was on the base board in the middle of the stack and had more than one bad chip, it is now a single 32K SRAM. I should look and see if the later modules that used a single 32K SRAM instead of 4 8K have a similar arrangement, if not I can always lift the pin and ground it.


Is that your document? I can fill in more of the pinout of the 1L?4 chip if you wish.
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RE: Found these inside a non-working 71B - Paul Berger (Canada) - 03-14-2018 04:20 PM
What's U10? - Dave Frederickson - 03-15-2018, 03:43 PM

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