[SMCARA] Help getting an old heathkit HF rig running

[Clarke, Tom AIR4.0P NATOPS]

 Hi Rich,

Welcome to ham radio!

There are a few of us here that appreciate "boatanchors" and "hollow
state" rigs!

For a tube radio that has been idle for a while, it is a good idea to
bring the AC line voltage up slowly over a period of several hours.
This requires the use of a Variac and some patience.  The idea here is
to slowly bring the capacitors and transformers up to temperature
without stressing them to failure.  A blown electrolytic cap is not a
pleasant thing to smell, when you "let the smoke out of it"!

Checking the tubes in a tube tester is a good idea also.  This will tell
you if the tube is basically OK, but often cannot tell you whether or
not it will work well in the rig.  Substitution is the way to check
that, as some tubes will work in one spot but not another.

Some folks recommend "shot gunning" the replacement of all caps in a
rig.  Paper caps and the so-called "black beauty" types are always
suspect.  Disc caps and micas tend not to go bad very often.  A leaky
interstage coupling cap can bias a tube into heavy conduction and create
other bad problems due to current and heat.  If a paper cap is bulging
or shows signs of stress (color, leaking "goo", etc), replace it.

The carbon resistors common to the 50-60s era have a tendency to drift
high in resistance, causing some strange things to happen. I have seen
100K resistors go up to 5 or 600K.  It is worth going through the rig
and check the resistor against the schematic of the color code on the
resistor. 

So, what next?

1.  Pop the hood and give it a good inspection looking for bad solder
joints, chaffed wires, bulging caps, burnt resistors.  Blow out the dust
and cobwebs too!  A little white lithium grease or 3in1 oil on gears and
mechanical things will help smooth them out. A squirt of tuner cleaner
or Caig De-Oxit on switch contacts and in variable resistor
(potentiometers) will help quiet things down.

2.  Make sure that the tubes are all in their correct locations.  Yep,
it happens! Run them thru the tube tester.

3.  Do the Variac process.  As you start to get up around 50-60 % line
voltage you may see the tubes start to glow (a good sign) and possibly
some noise coming out of the speaker.  That noise may be hum, which
would point to bad electrolytics in the power supply or HV rail bypasses
in the radio.  You might even hear signals!

4.  If after getting everything going at full line voltage and nothing
seems to work, it is time to check tubes and go through the voltage
chart in the radio's manual.  Start at the AF speaker end and work
toward the antenna input. The voltage checks can point to bad caps and
resistors.  The Heath book probably has a troubleshooting section that
will give you specifics. If you don't have a manual, get one!  There are
several vendors that offer copies. Google is your friend here.

5.  One thing to keep in mind is that this radio utilizes some pretty
high voltage (600-800 vDc as I recall) and can give you a "nasty bite"
or even make further life insurance premium payments unnecessary!  I
suspect that all of the "gray hairs" around here have been bitten and
that usually makes us very wary!  Keeping one hand in your pocket, while
working with the other is inconvenient, but does help you from
completing the circuit!

5. Ask questions.  Several of us in town have Variacs, tube testers,
junk boxes, etc and are happy to welcome another "thermionic valve
enthusiast" to our midst. 

73 Tom/W4OKW

-----Original Message-----
From: smcara-bounces at mailman.qth.net
[mailto:smcara-bounces at mailman.qth.net] On Behalf Of Rich Harris
Sent: Tuesday, August 02, 2011 8:05 PM
To: SMCARA at mailman.qth.net
Subject: [SMCARA] Help getting an old heathkit HF rig running

Hi,
First post here. Rich Harris KB3WDZ. I took Tom's course in June and
passed both Tech and General tests. I have my Father-in-law's old
heathkit 101 radio that hasn't been run in decades.In the next few weeks
I'd like to start getting it back in operating condition and  I
understand it requires some special treatment to get it running again.
Anyone out there who can guide me in the right direction?
Thanks,
Rich
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