DX-100B Problems Continued

[Chuck W4MIL]

GM Mike,


I don't have the 100B, but I have restored two DX-100's over the past
year.


Do you have any ham band crystals that you can substitute for the VFO?
That would be my first "test" suggestion.  Signals begin with the
VFO/crystal oscillator and unless those are correct, one can expect low
drive and low output at the far end.  That entire signal path should be
vetted thoroughly.


I would re-measure ALL tube pin voltages, concentrating on the HV or
plate side.  I would also measure the HV and LV plus bias supplies at
the output of their respective filters.  I assume you have replaced the
filter caps with fresh electrolytics?  I would follow the HV line to
each tube to be sure the voltage is correct.  Same for the LV and bias
voltages.


Does the HV meter reading correspond to the actual voltages measured in
the power supply?


Oxidized ground connections can be an issue.  Loosen, then re-torque
every screw in the rig.


Dirty contacts on wafer switches.  Starting with the VFO (internal) and
including the various wafers associated with the main bandswitch, i.e.,
oscillator/driver/amplifier sections.  Same for the CW/Phone and
Xtal/Vfo switch.


Since I don't have the 100B, I cannot comment to the wiring and
interconnection of the SSB unit.  Jumpers, etc. that might need to be
made if the SSB converter isn't used.


This sounds like a lot, but it's a procedure I pretty much follow on
rigs that might be working or semi-working (or dead).


Power supply first............ Individual tube pin readings
next............ VFO
output/frequency/alignment...............Oscillator
stage.........Driver stage.........then Finals and associated tuning
and loading controls/parts.


The usual result is that the rig works fb and comes up to power and
specs pretty easily.


Of course, mileage may vary by individual users.............. there is
no magic potion!    Hi Hi


Do hope this is of some help.


Gud luck, OM.............. you'll find it.


They are great rigs.


73 de W4MIL

Chuck



-----Original Message-----

From: Mike Hardie <mike46 at SHAW.CA>

To: HEATH at LISTSERV.TEMPE.GOV

Sent: Wed, 6 Feb 2008 6:20 pm

Subject: [HEATH-TEMPE] DX-100B Problems Continued



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