I found the location of the MW attenuator.......................it appears
that I will have to change the 150pF shunt cap at the filter input to 220pF,
to make the filter symmetrical. This is for the R8.
As far as the R7, the 25V power supply line for the tune voltage was only
7V. This is the reason the receiver only locks on the low ranges. Unless the
power supply board has gone through some sort of revision, somebody replaced
the 78L24 regulator with an LM317Z. The 78L24 is a low current 24V positive
regulator, while the 317 is an adjustable regulator. Totally different
pin-out from the original, and it would never work in this circuit.
Basically, there is a multivibrator circuit that provides 35VAC. This
voltage is full-wave rectified with a bridge consisting of r 1N4148s,
filtered, and applied to the 24V regulator.
I should be able to get it running, once I get the correct part.

Pete

"dxAce" wrote in message
...


Pete KE9OA wrote:

How did you guess?????????????????????????

They don't call me 'Ace' for nothing!

He's the guy!

Pete

"dxAce" wrote in message
...


Pete KE9OA wrote:

U bet you............I've got it apart right
now......................cleaning the contacts on the regulator board
got
the low end of the low band VCO working....................the high
band
VCO
only works up at MHz. I am thinking, that with the high S/N, it looks
like
the owner of this radio sold the R7A face plate to somebody and
installed
an
R7 faceplate on this radio before he moved it out.
I played a little bit with the R8...........now I see why everybody
likes
it
so much. I think I will modify it so the preamp works on all ranges,
that
is, after I remove that pesky MW attenuator. Nice receivers.

I just saw a message on the Drake reflector wondering about a possible
change
due to the serial number. Thought it must be an R7A vs. an R7.

Name Dan, by any chance?