New Member 1942 Plea

Womble

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Oct 12, 2009
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Hi Folks, I have a scruffy bootleg 1942 on the test bench at the moment and am at the stage where a working board would be really bloody helpful. Has anyone here got a 1942 (bootleg or original) board, plus either a logic probe or a scope and about ten minutes free to check a couple of things for me?

The only problem I have is that the bootleg board doesnt have any silkscreen grid locations on it so it might be hard for me to describe the chips in question.

First off - with the board in front of you and the edge connector pointing to the left, there are two 74LS174 chips, one above the other in the second column to the right of the edge connection, just above the dipswitches. I need to know what pin 9 on the 174s is doing, ie if its high, low or active, pin 9 is common on both 174s by the way.

The second bit I need my notes at home to describe, but I think I have a rotten track, I have a line that goes to the edge connector between boards, but never makes it to anywhere on the other board, might be corrosion on my chip legs leaving me without a beep on the continuity meter.

Shame there are no 1942 schematics out there :(

Thanks if anyone can help!
 
Cheers guys - ironically I fixed a 1943 board recently without even needing the manual, the 1942 board is more of a pain and sods law has it that there are no schematics for that. Sadly my question revolves around what a specific pin should connect to, architecturally the boards are only slightly similar so I cant infer anything from 1943 that would be valid fo 1942.
 
Thanks for the offer but I am in Australia, the postage would cost more than the board is worth.

Have actually just finished fixing the bootleg I have here, I disturbed the fault long enough to get some scrolling background so I hit my various question points with the scope and ruled out a lot of things as totally normal. Next step is to get the board in the sink for a damn good scrub, its filthy!
 
Next step is to get the board in the sink for a damn good scrub, its filthy!

I usually do that first. I find it hard to locate bad traces and cold solder points if it's covered in 20 years worth of dust and crud.

ken
 
Its not that bad, just grubby, am waiting for the weather to clear up, leaving the board out in the sun for a few hours would get it bone dry here.
 
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