[AMRadio] Suggestions for restoring a DX-100

[Jordan Arndt]

When I went to power up my DX-100 which had been idle for almost 30 years, I
used a variac... watch also for arcing around the rectifier tube bases... I ran
the power up to 120 Vac over a 6 hour period... no problems and all
Electrolytics showed less than 1% difference in voltage across them... I did get
some arcing around the Rectifier tube sockets, but it turned out to be residue
from someone prior cleaning detergent... a flush with distilled water after
using an old toothbrush to clean it solved that problem... Good Luck... 73 de
Jordan...

Bill Smith wrote:

> ----- Original Message -----
> From: "George Pritchard" <gpritchard at comtechpst.com>
> To: <amradio at mailman.qth.net>
> Sent: Wednesday, April 03, 2002 12:16 PM
> Subject: RE: [AMRadio] Suggestions for restoring a DX-100
>
> > Reforming caps, or verifying leakage on them is easy if you have one of
> > those older 0-400 VDC high voltage variable supplies (heathkits $10 at
> > fests). I used it to verify leakage on "New Old Stock" caps and noticed
> very
> > high leakage, >10 mA at only 100 Volts! I'd leave them at 100 volts until
> > leakage dropped to < 1 mA... then go up slowly to 200 volts, and wait
> again.
> > Repeat the process untill you get to 400 volts on the 450 volt rated caps
> > with less than 1 mA current.
>
> A good procedure.  Too bad it didn't help the electrolytics.
>
> >The oils will never fail. BTW... I used the
> > Heathkit supply to verify the shorted capacitors in the first place. It
> > saves fuses and possible the transformer!!! Good luck.
> > George AB2KC
>
> Sorry to say I now find that many, if not most smaller bathtubs (0.01, 0.5
> .1 mfd) of the WWII / 50's vintage are now developing leakage.  High voltage
> oil caps seem to be holding up (so far).
>
> 73 de Bill, AB6MT
> billsmith at ispwest.com
>
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