From: "Al Parker" 
Subject: Re: [drakelist] TR-4C


Hi Robert,
    That's an interesting combination of things.  I've put my notes in below
to show what's connected to what.  Except for R-45, they're all in the
235vdc supply to various tubes.  Not like a short in the 235v line, more
like 700++v on it, and the resistors see a large voltage drop across them.
Are you sure you weren't struck by lightning?  (not likely, but something
almost similarly catastrophic.)
    R-45 is a different animal, in the cathodes of the finals, only to gnd
on xmt.  It's the shunt for the plate current meter.  What's the meter look
like, needle bent?
    When was the last time the rig was used?  What have you changed since
then?  Is there more information available?  What's the pwr supply look like
inside?
    I can't solve the problem now, maybe somebody else has some ideas?
73,
Al, W8UT
New Bern, NC
BoatAnchors appreciated here
http://www.thecompendium.net/radio/
http://www.hammarlund.info


----- Original Message -----
From: "Robert Lawson" 
>
> R168  100 ohm  V17  pin 6
        235vdc line to pl & scr of aud out

>
> R71     220 ohm  1 watt  from pin 5 of V17 follow through to
"S" meter on
> schematic
        the dropping/isolation res. from the 250v line to the 235v line,
thru R-163, 47ohm;;  (also in the 235vdc line to pl & scr of aud out, in
series w/S-mtr, low current, most is thru R-168)
>
> R122 and  R26  both 1.5 kohm T7 and  T8  near V4 6EJ7 mixer on the
schematic
        235vdc line to mixer pl

>
> R45  2 ohm  in series with RFC-2 feeding the cathodes (pin 3) of V8 V9 V10
> (finals)
        to ground for the cath of finals on xmt only  - mtr shunt.

>
> Hope this helps you and all.  Thanks for you response to me.  I need all
the help
> I can get on this one.  Still looking for the short to ground in the 235
volt
> (white/orange) wire.
>
> 73 Robert WPE4FGR W4RL  Pensacola Florida
>

> > ----- Original Message -----
> > From: "Robert Lawson" 
> > To: 
> > Sent: Wednesday, July 30, 2003 12:42 PM
> > Subject: [drakelist] TR-4C
> >
> > >
> > > Hi Fellows,
> > >
> > > I need a big favor by way of good advice.  This is my first piece of
> > > Drake gear.
> > >
> > > Fired up (seems literally now that I think about it) my TR-4C this
> > > morning and smoked (burned in half)  resistors R168 100 ohm,  R71 220
> > > ohm,  R122 1.5k ohm,  R26 1.5k ohm,  R45  2 ohm,  and a 47 something
1/2
> > > watter bridging the two identical  1" by 1.5"
sized vertically
standing
> > > phenolic boards adjacent to the VOX gain pot.   Seems the white/orange
> > > wire is common to most resistors.  Yesterday the rig was working well.
> > >
> > > Any  ideas on why the resistors were ruined?  Bad electrolytic
(shorting
> > > to ground) in the rig downstream?
> > >
> > > Note my manual (original) does not have a parts list.
> > >
> > > Again,  sincere thanks for any help.
> > >
> > > 73 Robert



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