26 Nov
2002
26 Nov
'02
6:43 a.m.
Carlos Murillo wrote:
I've recently come across three pieces of vintage test
equipment;
---snip--
The Heathkit audio analyzer passed visual inspection
--snip--
The Precision signal tracer is not working; somebody
took off
the rectifier tube/valve and soldered a couple of diodes; I suspect
that at least one filament is open (pins 3 and 4, right?
--snip--
The Radiometer Copenhagen gear I haven't powered up
Now the question: can you please take a look and see
if
1) you have docs for any of these,
2) might guess what the operating procedures are and what the controls
and connectors are for? Some I can guess, others I don't know.
The Heathkit distortion analyzer used to be fairly common around AM
radio stations, as they used it for proof-of-performance testing. One
feeds an audio tone into an amplifier/console and the Heathkit is across
the output. Null the tone out, and what's left is harmonic
distortion/noise/hum etc.
The precision signal tracer is not much more than a very high gain audio
amp. The missing probe is just an AM detector, so that a modulated RF
signal can be followed in a radio. I'm wondering if those diodes are
replacing a 6X4, 6X5, or 5Y3, as the pins vary. If the tubes are all
6xxx numbers then it is tranformer operated, if they are different
numbers, it may be series string across the AC line and not worth
fixing. I've found them not all that useful, just makes troubleshooting
AM radios and audio amps a lot faster.
The Beat Frequency oscillator looks like a copy of a GR design. I think
all it may be is an audio oscillator on the order of the venerable HP
200CD, with variable output impedances.
It will be a good exercise of the grey matter getting them restored w/o
schematics. There might be info on the Web for those units, so keep
looking.
Gary Hildebrand
St. Joseph, MO