Post Reply 
Found these inside a non-working 71B
03-16-2018, 09:05 PM
Post: #115
RE: Found these inside a non-working 71B
(03-16-2018 03:19 PM)Dave Frederickson Wrote:  
(03-16-2018 01:55 AM)Paul Berger (Canada) Wrote:  If the "Disable Last Chip in Module" option is available on the CMT modules I don't think that it would be feasible to bring it out to one of the pads for a connector. These same modules are used in the CMT front plugin memory module. For default operation the "LCIM" pin is tied high. this would mean that if you used pin 11 which is OD in port 1 plugging the module into port 1 would disable the internal ROM. Pin 10 would not be useful either as it is int14 on all ports and is that pin is high it would always assert int14 which probably would not be good. Pin 13 can't be used either because on plugin modules it is expected top momentarily assert *INT. and when fully inserted this pin is grounded on the plugin side. Since it seem probable that the CMT EPROM programmer uses this function to switch between two 32K module and 1 64K module perhaps someone who has one of these could take a peek inside and see what the switch is wired up to.

I had taken apart a CMT front port module to wire it inside one of of my 71Bs and I preserved the shell and the connector pins. I just went and counted and there where 13 pins so they where contacts in the plugin for all 13 connections even though 2 of them are not used.


Realize that if you try this mod on a front-port module you may need to cut a trace. As this discussion pertains to the internally wired modules there's no connection between Pin 11 on the memory module and the ports of the 71.

Not sure what the issue is with Pin 13, GND, momentarily asserting *INT. Is that the "Module Pulled" mechanism?


My curiosity got the better of me and I looked inside my modded 71B and on the three modules inside, one of which I know for sure came from a CMT 32K front plugin and the other two look identical there is nothing connected to pin 11, and there is no obvious place to connect to LCIM, so the modules in the EPROM programmer must be different or modified since you say the switch is connected to pin 11. These modules also look the same as the ones that Mike posted the pictures of.

I meant pin 12 *int not 13 which is ground.

Find all posts by this user
Quote this message in a reply
Post Reply 

Messages In This Thread
What's U10? - Dave Frederickson - 03-15-2018, 03:43 PM
RE: Found these inside a non-working 71B - Paul Berger (Canada) - 03-16-2018 09:05 PM

User(s) browsing this thread: 1 Guest(s)