Archived posting to the Leica Users Group, 1999/08/18

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Subject: [Leica] R4 motor drive problem
From: "Javier Perez" <japho@cunyvm.cuny.edu>
Date: Thu, 19 Aug 1999 01:07:08 -0400

Hi All

I've got a problem with an R4 motor drive
and was hoping someone could help.
Years ago while experimenting I tried to connect a power source
to the accessory jack and blew the thing.
It only works on single or 4 fps modes and the
double exposure beeper stays on all the time.
as a quick fix I disconnected the Piezo beeper
back then but now I'de like to get the thing working for real.
Inside I noticed 2 miniature surface mounted 14 pin DIPS
labeled 4011BT and 4093BT. After some searching
I managed to trace these to Philips. Both are quad double input nands with
the
4093 having a shmidtt trigger built in.
Since all the diodes and passive components test out ok I
assume that one or both of these chips are responsible.
So here's my question.
Does anyone know which one of these would cause the problem?
Also, anybody got some for sale?
Finally, In case the repair fails
Dioes anybody have a really beat up but electronically ok R4 drive for sale?
Please let me know
Best Regards
Javier