[AMRadio] Suggestions for restoring a DX-100

[Bill Smith]

I rebuild my AR-88 and BC-779 by removing the screws from the bathtubs,
opening the back of the capacitors with a Dremel and carborundum wheel,
peeling back the back, removing the guts (and the oil), replacing with new
caps, folding the back flap back and putting the cap back, all without
unsoldering.  Inside looks original, and sets work great.

Haven't died yet from exposure to PCB.  Think I tested the oil and found it
was mineral oil.  Test is to dip a paper towel in the oil, take it outside
and try to burn it.  If it burns, it is mineral oil.  If you can't get it to
burn, it is likely PCB.  Do not smell the vapor, reportedly, PCB's are toxic
only when heated to high temperature.

And.. believe there is still controversy whether PCB's are the nemesis they
have reported to be.

73 de Bill, AB6MT
billsmith at ispwest.com


----- Original Message -----
From: "Jordan Arndt" <jordana at nucleus.com>
To: <amradio at mailman.qth.net>
Sent: Wednesday, April 03, 2002 2:31 PM
Subject: Re: [AMRadio] Suggestions for restoring a DX-100


> I've seen a few AR-88's c.1944 with both electrically and physically leaky
> bathtubs... usually around the seals, and occasionally around the soldered
seem
> also... 73 de Jordan...
>
> George Pritchard wrote:
>
> > My friend KH6U has an R-388 (as I do). He said the same thing about the
> > bath-tubs. Fortunately, I have not yet had that problem, only leaky
faucets
> > in the bath tub, Hi Hi,
> > George KC
> >
> > -----Original Message-----
> > From: amradio-admin at mailman.qth.net
> > [mailto:amradio-admin at mailman.qth.net]On Behalf Of Bill Smith
> > Sent: Wednesday, April 03, 2002 5:01 PM
> > To: amradio at mailman.qth.net
> > Subject: Re: [AMRadio] Suggestions for restoring a DX-100
> >
> > ----- 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
> >
> > _______________________________________________
> > AMRadio mailing list
> > AMRadio at mailman.qth.net
> > http://mailman.qth.net/mailman/listinfo/amradio
> >
> > _______________________________________________
> > AMRadio mailing list
> > AMRadio at mailman.qth.net
> > http://mailman.qth.net/mailman/listinfo/amradio
>
> George Pritchard wrote:
>
> > My friend KH6U has an R-388 (as I do). He said the same thing about the
> > bath-tubs. Fortunately, I have not yet had that problem, only leaky
faucets
> > in the bath tub, Hi Hi,
> > George KC
> >
> > -----Original Message-----
> > From: amradio-admin at mailman.qth.net
> > [mailto:amradio-admin at mailman.qth.net]On Behalf Of Bill Smith
> > Sent: Wednesday, April 03, 2002 5:01 PM
> > To: amradio at mailman.qth.net
> > Subject: Re: [AMRadio] Suggestions for restoring a DX-100
> >
> > ----- 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
> >
> > _______________________________________________
> > AMRadio mailing list
> > AMRadio at mailman.qth.net
> > http://mailman.qth.net/mailman/listinfo/amradio
> >
> > _______________________________________________
> > AMRadio mailing list
> > AMRadio at mailman.qth.net
> > http://mailman.qth.net/mailman/listinfo/amradio
>
> _______________________________________________
> AMRadio mailing list
> AMRadio at mailman.qth.net
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