DX-60A schematic needed, or just PS differences among DX-60A, -60, and -60B

[Christopher J Galbraith]

Hi gang,

My latest project is getting a DX-60A on the air.  It was my dream rig when
I was a Novice, even though that was in the early 80s (I just always liked
this transmitter)!

Long story short--I could really use a scan of a DX-60A schematic.  I have
schematics for the DX-60 and DX-60B but they are quite different from mine.
I would be most grateful if someone could send me an electronic version of
the DX-60A schematic, or even just tell me the differences between the power
supply circuits in the DX-60A and DX-60 or DX-60B.  I'll explain more if you
care to read it...

I recapped the power supply and audio section, made some other minor repairs
(burnt 8.2 Ohm cathode current metering resistor, added a snubber RC across
the HV function switch contacts, etc.) and she is tuning up like a champion
(50W out easy, smooth tuning, lots of grid drive).  But, there is a very
severe hum on the carrier, in both CW and AM.  The hum is roughly centered
at 120 Hz based on the scope pattern (it is more like a ramp function
though).

I do not have a schematic for the DX-60A (nor is there one on BAMA or the
other usual sources on the net), but I have traced the circuit and compared
it to the DX-60 and DX-60B.  Compared to the earlier and later models, this
transmitter has only (3) 40uF/450V capacitors instead of (4).  In effect,
the high voltage to the 6146 PA and 6DE7 (modulator) is coming directly from
the top of the voltage doubler capacitor stack.  A quick simulation shows
that this node has about 50Vp-p of ripple!

So, did Heath really cut corners on the DX-60A power supply, or was mine
miswired or lose a capacitor along the way?

Thanks for any help,

73, Chris KA8WFC

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