[Drake] TR-7 Alignment error

[John [GM1BSG]]

Hi all,

I have had this repair around for some time and guess its time for the
crunch.

It is a beautiful example of a fully loaded TR-7, with all original
documentation, the works. It is actually nearly in better condition than my
Pro II!

It arrived to me through a local club member who reported it as being deaf.
Initially I thought he mean't quiet, which they are anyway, but no, it was
deaf. With 30uV in I was getting more like S4, not S9

The 10V rail was very low at 8.2V, touching the pot to reset it produced
some rather sharp spikes, so I changed the pot and adjusted back to 10V. I
will assume for now that old age had caught up with it but started a
re-alignemnet anyway.

All Ok till... the following procedure in the manuals 3.1 to calibrate the S
meter failed.

Setting R1128 / R1129 was OK, but after turning the RFG back and trying to
set R1105, no way, the adjustment is simply not enough by a long way. Again
fed from the tests set @ 30uV, still around S4. Not good.

The 5V and -5V rails also now look on the low side, certainly the 5V being
low is not what I would expect from a 7805 with an input of 10V

I do not thin it has been tampered with in any way. Although the only part
of the manual with any marks on it is the section on the 2nd IF/Audio board
which has 2 crosses around one end of C/R1102 C/R1121 area. Does not look
good considering what those stages do.

If anyone has any suggestions it would be appreciated before I go to the
effort of making some riser cards to look further. Considering the condition
of the set I would like to get a bit more insight / advice before doing
battle on the bench. 

Thanks

John