Garey Barrell <[EMAIL PROTECTED]> made an utterance to the drakelist gang
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Hubert -
Check the +11V power supply, which is derived from the +150 supply.
Check for ripple on the +150V and C165. Sounds like the correct 10V
Zener inside the PTO doesn't have enough 'headroom' from the +11V and is
dropping out of regulation.
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 4-B & C-Line Service Supplement CDs
<www.k4oah.com>
Hubert ROTH wrote:
"Hubert ROTH" <[EMAIL PROTECTED]> made an utterance to the drakelist gang
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Hello I am putting on the air a Drake Cline. R-4C sn 25508 has
following problems. While tuned on a frequency frequency is juming a
few hertz erraticaly. Hardly noticable on SSB but awfull in CW.
I cleaned mechanism tryed to ground the yoke and ended up with a
completely dismantled PTO lying on y bench and still jittering. Power
up by a lab supply.
I changed the resistors the FET the buffer and several NP0 caps. Only
if I replace the Zener diode by a 7.5V it gets stable. I monitor on a
receiver tuned lets say on 5000Khz and with a hp8568 spectrum analyzer.
With the 7.5V zener output is not enough for driving the mixer so I
put a little amp at the output but I still low and 2 S points down
against the T4X PTO
So do you have any ideas or a spare PTO :)
Best 73,s Hubert F6DUK
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