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    Mark II Power Transformer



    Posts : 3
    Join date : 2013-07-21

    Mark II Power Transformer

    Post by Backpacker85 on Sat Feb 01, 2014 7:04 pm

    First of all, thanks to all for the great information available on this forum.
    Now for my "new" issue:

    Rebuilding a pair of old Mark II's and have a question on the transformers. I know I read a thread on here earlier of some tests that can be made on both the OPT's and the PT's when off-chassis, but it was addressing the Mark III transformers. Not so worried about the OPT values, since they are the same on the Mark II and MARK III, but what of the PT values? Would the voltage values mentioned in that thread be similar for the P782 transformers on a Mark II? Sorry, but I can't locate the thread, or I'd post a link for reference.

    Thanks in advance for any insight.


    Posts : 3
    Join date : 2013-07-21


    Post by Backpacker85 on Sat Feb 01, 2014 7:25 pm

    Must have been a "senior moment". It's the OPT's that are different between the Mark II and the Mark III.....PT's (P-782) are the same, I think, so I may have just answered my own question.......

    Same voltage readings as mentioned in the Mark III thread, correct?

    Posts : 195
    Join date : 2008-12-01

    MK II Transformers

    Post by DynakitParts on Sat Feb 01, 2014 7:34 pm

        The power transformer P-782 for the MK II & MK III are the same. Accordingly you can expect the voltage readings to be the same when bench tested (out of circuit).

    However...the outputs are different. The MK II original output transformer only has 8 & 16 ohm taps whereas the MK III (A-431) had 4, 8 & 16 ohm taps. With one less winding the resistance measurements may be different than the MK III (A-431) ...suggest you just compare the measurements of one output to the other. It's unlikely that both units are bad?

    Kevin @ Dynakit

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