[net.ham-radio] 930/430 S meter mods & Saving the 2 meter band

rjr@mgweed.UUCP (Bob Roehrig) (09/19/85)

I showed the articles from the GEARVAKF newsletter to a friend of mine (Bill, 
KA9HVU) and received the following response which may be of use to others:

"Yeah, I got the eye in my 430, but the author of the article is in dire
need of training in modification applications. The job was much easier
than I had expected, but I made some changes in the suggested proceedure.
Removing the meter was quite simple with the aid of a MOTO-TOOL and a
cutting blade. As for the bezel, it was easily cut with a deburring tool
in an electric drill. I had a nice, almost new bezel in the junk box so
cutting a new one from a SUCRETS can was not necessary (this also saved
having to paint). The filament transformer is larger than I would like for
a neat appearance, so I have it hung from the wires behind the rig - out of
sight. This, however, limits the use of the 430 in the mobile which I ain't
done yet."

Bill also gives some advice on preventing the explosion of the 2 meter band:

"A simple way to prevent the possible explosion of the 2 meter band would be
to relieve the pressure that continues to build. It seems to me that a small
penetration of the band sufficient to release some of the pressure, but not
so large that it would allow the escape of some of the 2 meter frequencies,
would solve the problem nicely. The best place to make the penetration would
be at the band edge where it could be closely monitored just in case it
would start to tear and grow too large. As for a means of penetration, a
shaft of suitable size with the ability to enlarge or shrink itself, and
with a vent hole through its length could be inserted and left as long as
necessary. The elastigmity of the band should prevent the escape of the
shaft and if the vent was no longer required, then the hole could be plugged."

Relayed by K9EUI

jhs@mitre-bedford.ARPA (09/24/85)

Re: 430 mods -

I have found that room can be found for most any modification if one uses
the following simple procedure:

Obtain from the factory a matching empty housing and blank panel, preferably
painted.  Saw the original unit down the right-hand side with a band saw,
taking care not to saw through too many circuit board foils, switch wafers,
and the like.  Often this can be avoided by bending these critical items out
of the way of the saw track with gas pliers or vise-grips, before commencing
the sawing operation.  Saw down the opposite side of the empty housing, taking
off just the side of the housing if maximum space is desired, or closer to
the center line if a more compact modified unit is required.  Weld the new
empty housing extension onto the original TS-430 housing using Heliarc
equipment for best results.  To avoid warping or damage to sensitive
solid-state components, care should be taken to minimize overall package
temperature rise, and the entire assembly should be cooled quickly by plunging
it into a water bath, preferably salt water, immediately upon completing the
weld.

The weld seam may then be smoothed using a bench grinder for rough areas and
a disk sander for the final finish.  It may be necessary to touch up the
painting if a clean appearance is desired.  If so, paint adhesion will be
improved if an etchant such as MetalPrep (basically phosphoric acid) is
painted onto the bare metal surface and then rinsed off after allowing it
to etch the metal for a few minutes.  Take care not to drip too much of the
acid inside the equipment as it may affect circuit board and connector
reliability.

With these simple procedures, the experimenter can greatly expand the space
available in the 430 and similar transceivers for custom circuit additions.

						73,
						John S., W3IKG