6
1, REPAIR AND REFURBISHING
This document is written with the assumption that the restorer has a basic understanding of circuit and tube theory.
In Section 1 you will find the test and alignment procedures. If a particular process does not function as
described you will proceed to the appropriate subsection of section
2, SUBSYSTEM TROUBLE SHOOTING
for fault analysis. Section 3 ATTACHMENTS contains additional information on the system and a subsection
of data sheets. You can copy the data sheets to record data as you perform system analysis. A complete
cleaning and mechanical inspection are always advised. Cleaning of the rotary switches and the relays is of
particular importance. Go to
https://wd0gof.files.wordpress.com/2019/02/rig-cleaning.pdf
used for 20 years. After a thorough cleaning do a close visual inspection. Look closely for broken or burned
components. Check the rotation of the controls and mechanical stops of the main tuning dial. Try to eliminate
the mechanical problems first. Inspect L28 for heat deformation on the end furthest from the chassis side panel.
This is a high failure rate item when the rig is mistuned or misused.
1-1, RECAPPING
There is one dual section capacitor that is a must replace item. C91A and B can be replaced with custom made
dual capacitors or two individual capacitors positioned under the chassis. Either way you should seek out very
low ESR rated capacitors. ESR’s of 0.5 ohm and lower are available. I prefer ESR of 0.05 or less. There is
much discussion about the Plastic Mica and the Ceramic Tubular caps used in the 44. You must follow your
heart here. I do not replace them unless I find a bad one.
1-2, AFTERMARKET MODIFICATIONS
It is rare to find a unit that has not been modified or “improved” by a previous owner. As a general rule you are
better off striping all the mods and returning the rig to its original condition.
1-3 TEST EQUIPMENT REQUIRED
•
Dummy key plug (key plug with no connections).
•
Scope, 100mhZ BANDWIDTH, 1X, 10X PROBES
•
Two multimeters, no need to spend a lot of money here. One small VOM with a 2.5 vdc and 10vdc range
dedicated to plate current setup and monitoring. The second meter can be a Harbor Freight $6 - $10 DVM.
•
Frequency counter, 1.6 – 40MHz
•
https://wd0gof.com/hallicrafters-radio/technical-discussions/ht/ht-miscellaneous/
and click on
SR & HT
SERIES MIC SELECTION.
•
Telegraph key
•
Hf Signal generator
•
Dummy load/wattmeter
•
Microphone patch cable
•
Driver tube capacitive pick-up (see 2-2-4)
As a general rule I have tried to eliminate specialized or expensive test equipment. Systems like the HT-44
cause me to make acceptation. The phasing adjustments of the balanced modulators as described in the manual
can be quite tedious. When you have completed the process all you really know is that you have completed the
process. A spectrum analyzer turns the 10minute to ½ hour process into a minute and a half process with
definitive, measurable results. Do not get carried away with features. Center frequency 7.23MHz, bandwidth
0.3KHz and 0.5KHz/division. Search eham and qrz classified ads.