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Found these inside a non-working 71B
03-12-2018, 02:58 AM (This post was last modified: 03-12-2018 03:37 AM by MikeSD.)
Post: #43
RE: Found these inside a non-working 71B
(03-12-2018 02:03 AM)Paul Berger (Canada) Wrote:  It looks like you have 8 sequential connections starting from the left there should only be 7 the 8th wire will be connecting Din on U9 to Din on one of the 32Ks that will mean that when Din goes high there both modules will try to talk at the same time resulting in chaos and likely neither module being configured, you want to remove that wire and the one you picked up under the resistor should go to Din on the 32K that has Dout wired to Din on the other 32K you don't need to connect Dout on the second one to anything.


I'm sure uou are probably right but this is far fewer than the way it was, since I had a FORTH too.

I'm not sure you are understanding how the 32K are wired, assuming both b are the same.
* what are the 8 connections you are referring to. There are the original 5 chips and I'm adding 2. With forth and Math there are 2 more there. So I'm confused about the connections.
* that said, there was a daisy chain error. I had Pin9 from bottom chip to pin 8 of the front chip. Should have been back chip. Pin9 of back chip wire in module to pin 8 of front chip. Then Pin9 of front chip goes to HPIL. Same results.

update: Dang on way to Subway I realized there is another problem. I never cut a trace between the lower chip pin9 and the HPIL. My RAM was not inserted between. So when i ran U9-pin 9 to the RAM chip pin8 and it's pin 9 to the front RAM pin8, , its pin 9 is routed back to pin 9 on lower chip because I did cut the chain between U9 and HPIL Havent looked at why but i know its wrong. kind of a parallel connection. I think the 2nd RAM would prevent the first one from configuring.

If this was all working, would MEM return 82k. or would it look like a 64k port ram?
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RE: Found these inside a non-working 71B - MikeSD - 03-12-2018 02:58 AM
What's U10? - Dave Frederickson - 03-15-2018, 03:43 PM

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