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Last update: 03/06/01 13.12.00 |
Hallicrafters SX-28
Restoration Project
Back in 1994 I've been
given an unknown very old radio receiver identified as an Hallicrafter SX-28 by
my old friend Francesco.
At that time I was not
interested in old radio at all. I had a quick look on the Internet but I was
not able to find anything useful to help in "repairing" that
radio.
Because of its weight and
dimensions I never gave back the radio to Francesco and the rig has been stored
in my own cellar for about 5 years.
During spring 1999,
housekeeping my cellar, I had a chance to have a look at that very old radio
again. It was dirty, ruined, yellowed with age, .... but starting looking
behind the scenes I discovered it fascinating.
Have a look at it resting,
… but waiting for life to come back:
I was back to the Internet
in a few minutes and searching for SX-28 I discovered that much more
information was available than before, including manuals and schematics. I also
discovered the boatanchors' world.
After a couple of weeks of
hard research work I decided to start a "restoration project".
Please note that this is conceptually completely different from "repairing".
The goals of the project
were identified in:
- bring the rig back to life, with all
functions operational at a reasonable level
- keep it as much original as possible (a
must in the visible parts)
- restore its original appearance as much as
possible
- no significant time constraint is present
even if the estimated time shouldn't exceed one year
- learn, learn, learn and learn. Share,
share, share and share.
So I have organized the
project in some major phases. You will recognize them in the activities
detailed in the restoration log.
Brand/model information
collection
This phase is aimed to
collect all the information needed for the project. From my point of view it
consists of intensively search the Internet for schematics, manuals and generic
info. Look search engines for the name of the rig, model and brand. I also subscribed
and stayed tuned with the rec.radio.amateur.boatanchors and rec.antiques.radio+phono
newsgroups and post some generic question concerning restoring tips for that
rig.
I have also collected a list of potential partners (people who cleverly
answered my questions or declared to have been involved in restoring an SX-28)
I probably have to refer to during the project.
So I have produced two documents: RDD (Radio Description Document) and PCL
(Project Contacts List); these two documents will be continuously updated
during the project.
The PCL is a simple xls
file containing an entry for every people I have got in touch with during the
project.
The RDD is a much more
complex document. It is a "multimedia" file containing manuals,
schematics, mails, news, pictures and any other type of information I have got
on SX-28s.
I have created a new
directory on my PC and a folder on my shelf to retain all the collected
information, electronically or on paper.
Risk analysis
I have identified the
following risks
- my friend Francesco won't sell me the
radio
- I'll find one of the vital component
broken and I am not able to find replacement
- I will definitively brake some of the
vital components (electronic or mechanical) of the rig
- I won't be able to fix electronics because
of my scarce knowledge in electronics repair
- Lab equipment is missing or not up to
speed to the task.
- Once disassembled I won't be able to
reassemble it again
Some of the activities in
my log can be recognized as attempt to eliminate or mitigate these risks.
Specific information
collection
This phase is aimed to
collect all the possible information about my own rig before starting working
on it. The reason for this being to understand the radio I am about to work on,
to check its real status, to assemble a file containing information that can be
used when I am half way (think of reassembling a part you have forgotten how it
was originally mounted…).
A new document, called PRDD
(Pre Restoration Description Document) has been created. It contains a lot of
pictures with descriptions in them (knobs positions, modules positions, wiring,
etc.). The chassis has been divided into 24 zones and each zone further divided
by sub zones A and B for reference. For every sub zone a digitalized image has
been taken by mean of my webcam.
You'll find all of these items in the restoration log.
Restoration phases
For the actual restoration
I have chosen to follow a step-by-step approach, backtracking the radio
circuitry: starting form the LF-amplifier back to the first tuning stage.
For every stage the plan is
to:
- understand it as much as possible
(learning phase) involving the BA community on the Net
- document all my findings and possibly
publishing them to the Net (sharing phase - this site)
- restore it if necessary (restoring phase)
project close down and
celebration party
If it will ever happen:
ditto.
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Last update: 27/05/01 0.31.00 |