[Test-Equipment] MC8309P

[gil smith]

>A friend and I are trying to repair an old HP counter (HP 5345A). One of its
>faults is a failed HP 1820-0610 , which has the commercial equivalent
MC8309P.
>Does anyone on this list know a reasonably priced source of 
>MC8309P?.  Alternatively, I understand that this is a TTL part...

Hi Stewart:

I tossed my old Motorola books years ago, so I can't help you on a spec
sheet.  From a quick peek at my 5345 manual, I found some of these chips on
the A-11 board -- they are dual 4-to-1 multiplexers, in TTL.  

You might check with replacement parts companies like NTE or SK.  If they
have a direct replacement, it'll be pricey, but also a clean repair.  NTE
might be in the Mosuer or DigiKey catalogs.

The closest ttl part (I think) is an LS153, but it has a different pinout.
If you can't find an actual 8309, you could possibly patch an LS153 in its
place (eg: bend up/trim-down the pins, glue it in place of the 8309, and
wire as nesessary).  Is the 8309 a 14-pin dip?  The LS153 has 16 (it has
two stobe lines that need to be pulled to ground).  A little ugly, but
likely workable.

gil


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