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Motorola supplementary TO3 stamp codes

Discussion in 'Electronic Repair' started by N_Cook, Dec 18, 2009.

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  1. N_Cook

    N_Cook Guest

    I can't say I'd noticed them before today
    Is there a cross-reference anwhere ? not necessary this time but if the
    printed marking is faded/damaged/burnt/ground off, another time

    A batch of 1988 MJ150024 with stamped code D14 around a mounting hole
    batch of 1988 MJ15025 stamp code D13
    1979 MJ15003 double stamped 924 CD

    I don't know if UK amp maker "Exposure" uses rebadged Motorola but marked
    EXP8P (pnp) and stamped C5 in similar position
    EXP8N (npn) stamped C4 in an Exposure VIII of 1988

    If anyone else cares to add here a few more they have lying around it may be
    useful sometime
     
  2. N_Cook

    N_Cook Guest

    the 924 one may be a supplemental metalwork datecode without the 7,
    preceeding the printed datecode of 7927 nand CD is the typecode for that one
     
  3. N_Cook

    N_Cook Guest


    Would there be a correlation between those stamp codes and the printed type
    number and so of some use to repair folk or would there be too much
    one-to-many mapping rather than 1 to 1? one stamp code used for dozens of
    types so not much use outside Motorola.
     
  4. N_Cook

    N_Cook Guest


    In the vintage valve/tube world these
    http://www.audiotubes.com/mullcode.htm
    small etched codes are very useful where the chalky printed type numbers
    have diasappeared off the glass envelopes
     
  5. Phil Allison

    Phil Allison Guest

    "N_Kook"
    ** Been there since the 1970s.

    They stopped doing it in the early 90s.

    ** Not one you can easily access.

    ** Identifies the part number of the chip in the pack.

    Motorola applied inked numbers at a later date, when orders were being
    filled.

    ** The "924" indicates it was assembled in the 24th week of 1979.

    "CD" indicates an MJ15003.

    "BP" indicates a 2N3055.

    "DID" indicates an MJ15024

    "DIB" indicates an MJ15015

    "34P" also indicates an MJ15003

    "CFF" and "CFFY" indicate an MJ423

    "CAH " indicates an MJ1800


    All this was very important to know back in the 1980s when I first came
    across a whole variety of FAKED Motorola parts at " Dick Smith Electronics
    " - and also at Rod Irving Electronics with Motorola 2N3055s and MJ2955s
    that had been scrubbed and relabelled as MJ15003s and MJ15004s.

    Nasty business.

    Lawyers even got involved.


    ..... Phil
     
  6. N_Cook

    N_Cook Guest


    That is the sort of correlation I was after. I take it there was a simple
    correlation in the late 70s but by the late 80s it was no longer the case.
    I see TO3 , RCA make ones also have such punched numbers, but more complex
    spaced characters
     
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