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Info on MDB Line Printer Controller 40940?

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fritzm

Experienced Member
Joined
Dec 11, 2011
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142
Location
Oakland, CA
I have a line printer controller card from MDB systems, #40940 (pic below). Does anybody have docs or recall anything about this card? If I recall, this came into my collection along with an LA30p some time ago, so I'm assuming its a parallel i/o interface.

I'm also assuming it will mimic one of the common DEC peripheral interfaces, so it probably wouldn't be too hard to just plug it in and sleuth it out. But it would be nice to know jumpering options, etc, or have a schematic on hand if it needs debug/repair.

MDB Printer Controller.jpg
 
There is an MDB MLSI-LP11 Instruction Manual on eBay from a vendor that I have done business with.
I didn't see your board's part number on the manual.

Maybe the DEC LP11 or LPV11 schematic is close.
 
We used to support a PDP-8/E system with a CDC drum printer. This board looks somewhat similar to the controller from the 8, but memory is pretty fuzzy after 40 years :) I don't know how to differentiate an omnibus board from a unibus board by visual inspection.
 
Doug G said:
We used to support a PDP-8/E system with a CDC drum printer. This board looks somewhat similar to the controller from the 8, but memory is pretty fuzzy after 40 years :) I don't know how to differentiate an omnibus board from a unibus board by visual inspection.
Click to expand...

Well, the etch at the top of the image says 'PDP-11 LINE PRINTER CONTROLLER' (fuzzy but readable) so it is likely something like a DEC LP11 M7528 clone.
 
M7258 you mean? This would fit in the C-F connectors of a SPC UNIBUS backplane slot. Without a removable timing priority jumper, perhaps hard-wired to match the job the specs of the system that used the non-dec (?) line printer.
 
billdeg said:
M7258 you mean? This would fit in the C-F connectors of a SPC UNIBUS backplane slot. Without a removable timing priority jumper, perhaps hard-wired to match the job the specs of the system that used the non-dec (?) line printer.
Click to expand...

Sorry I swapped the digits in the module number. C-F of a UNIBUS backplane (SPC) slot is correct. Likely designed to work at priority BR4 only like the standard LP11.
 
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