Power and interface
connectors are available through:
William
Perry Co (Email
address no longer working.)
702 (Rear) Beechwood Rd, Louisville, KY, 40207 (502) 893-8724, FAX
(502) 893-9220
The power connector part
number is 97-3106A20-8S (MS3106A20-8S) (order with the clamp).
The connectors for the
coupler cable are MS3106A20-27P and MS3106A20-27S (also order with
the clamp).
MY HARRIS STATION:
(2) Harris RT-1446
(RF-350K)
Harris Remote Control Unit C-11329
Harris AM-7223 500 Watt Auto Tune Amplifier
Harris CU-2310 500 Watt Auto Antenna Coupler
1000' of control cable for the remote! (Incoming won't hit the
station!)
I'm posting information on
these pages that I hope others will find helpful when working on
this gear. Not everyone will experience the same problems or
solutions but like learning anything, why reinvent the wheel? I
know I've learned a lot from others who have worked on this gear
which saved me valuable time. Keep in mind that you'll never know
what condition you'll find your equipment if you buy it sight
unseen.
Contact me at 'mycallsign' at qwest.net.
(Yes, that's a J-37
mounted on an aluminum plate. )
I've read some comments on
the 'net about this equipment and have to add my comments also.
Some have 'rated' this equipment as '1' (poor) based on the fact
that:
it doesn't have a knob for
vfo and you can't 'search' the bands
it's an old boat anchor
it's heavy
performance is poor.
Let's go over these
issues:
1. No VFO. It wasn't
designed with one. It's not a 'ham' radio. Don't fault this rig
because it doesn't have a bell or whistle YOU want. For what it
was designed for, it is a superior piece of communication
equipment. It's made to park on a frequency and communicate with
another station. It's not a 'search' receiver. Compare amateur
radio equipment from the same era to this gear and then current
ham gear. How many hams have HF stations that you can dial ANY
frequency, key the mic, and transmit and have the amplifier and
antenna coupler already tuned. ???
2. Boat anchor. I always
pictured a 'boat anchor' as a piece of gear that sat in the corner
and you couldn't pay anyone to haul away. This is FAR from the
truth. Check some of the prices the market is demanding for this
stuff.
3. It's heavy. Yes it is.
It weighs much more than my Icom IC-706MkIIg. But if my Icom
fails, I have to send it to Icom and pay many $$$$$$ to get
repaired. I refer you to the rest of this page. (There are no
2N2222's in my Icom.)
4. Performance. HA!
They've obviously never listened to the transmitted audio of a
Harris! And....it may not have all the fancy bandpass filters and
DSP and such, but just look at the size of the filters compared to
the ones in ANY ham rig.
You see, everyone has an
opinion, but DON'T 'fault' a piece of equipment just because it
doesn't suit YOUR needs.
8/8/07 UPDATE BY BUD/KA0CBO/AFA3WS
I refer you to module A1A14A1 known as the multivoltage supply
located inside of the radio itself. As with the 12 volt converter
inside of the power supply, this also should be serviced even if
it is NOT showing any signs of failure yet. This is a vital link
in good operations of the radio and the electrolytic caps inside
of it also need to all be replaced. If for no other reason than
they are exactly the same age as the ones you already found bad. I
strongly recommend replacing those caps with the 105C temperature
types. That is a toaster oven inside and the more common 85C types
will not hold up very long. I might also mention, of all of the
radios I have serviced here myself, every single one of them has
had errors of some type related to the LPF board. Removing all
relays and burnishing the contacts in them one by one is the
single best way to correct those problems. They are all but
impossible to find and the ones I have are pricey as they are out
of production.
Harris Remote Control Unit
C-11329/URC
The Harris remote is a fairly
rare item. In fact, this is the only one I've ever seen. When
dealing with equipment of this type from the 80's, you can expect,
and in fact it did happen, to experience cascading tantalum bypass
capacitor failure. The integrated circuits in these units have
their B+ lines bypassed to ground using tantalum capacitors.
These capacitors are reaching the end of their lifespan. When
first powered on, the unit flashed a display and then went dead.
It wasn't until after checking the normal obvious possibilities of
the failure such as fuses and obviously failed components and
turning the unit on for a bit longer, that the first capacitor
failed and immediately filled the room with thick, nasty, yellow
smoke. Replacing that capacitor brought the unit to life but only
for a second until the second capacitor failed. The power chain
stabilized after replacing three capacitors, however, a similar
piece of equipment put into service by a friend, required that
over 20 tantalums be replaced before the unit was usable.
This unit can be interfaced
with the R/T using several interfaces and protocols. I first
tried the RS-232 method, but could not get any communication
between the units. I then tried the RS-422 and even through 1000'
of cable, the unit works flawlessly. Since the different
interfaces use different drivers, it's possible a driver IC has
failed...or I had a poor connection in a cable!
Harris RT-1446 (RF-350K)
My second R/T had some
issues. It was basically a parts radio and the power supply had
ended up in a dumpster (which I rescued long ago!) Acquiring a
second dead supply gave me parts to help troubleshoot the
problem(s). Having first determined (incorrectly) that the
rectifiers were bad, I replaced them with new ones only to find
nothing had changed. I had been looking at the waveform at the
end of the bridge and one leg of the bridge would not cut off to
zero. Using a junk box bridge, the waveform was fine. After many
tries with different transformers and rectifiers, I gave up trying
to improve the waveform and worked on other problems. Symptoms
were, no step-start, no fan voltage and no voltage to the A2A2
section (below). Attempting to bypass the step-start by manually
closing the step-start relay resulted in obvious high current
drain (the lights dimmed) with no load. It took only a second to
hear a sizzle coming from the A2A2 which was traced to a shorted
capacitor. Replacing it with the spare and then manually
activating the relay gave me good power out, however, the fan and
step-start still did not work.
I replaced the A2A1
Protection and Control Assy with the spare and no improvement.
Either both boards were bad (same problem) or the problem was
external to the board. The only external components left to check
would be the power resistors and the relay itself (not likely as
it wouldn't affect the fan).
Early on, I had checked the
value of the 1 ohm 50W resistor across the contacts of the step
start relay. Let this be a lesson, that even though something
looks right, don't rule it out. The resistor still reads 1 ohm,
but replacing it with the spare brought the step start circuitry
to life!
The last problem to solve was
the fan. After hours of swapping boards, pouring over schematics
and measuring voltages I came to the conclusion that the fan
problem was also external to the board. Positive voltages on both
terminals of the fan caused R38 to sink to ground and get HOT. I
admit the schematics as printed are tiny, but familiarity with RED
being positive was the downfall to this problem. RED is attached
to the negative terminal of the fan, and the schematic even says
so. The fan must have a built in diode that passes the voltage
through the fan to ground if the wires are reversed. If you look
at how the fan speed is varied, this would make sense.
The reassembled and
functioning power supply.
A few days after finishing
with the power supply, I decided to dress up and reroute some of
the wiring back to a semi-original configuration. After doing so,
the radio would die when keying the mic. With symptoms of low
current capacity, I replaced a rectifier that appeared to have a
loose center post but there was no improvement. To make a long
story short, one of the yellow secondary wires from the
transformer to the rectifier assembly is routed along the A1 board
towards the rear of the chassis and then back to the rectifiers.
The wire was pushed too far down and was preventing the step-start
relay from engaging although the A1 circuitry was energizing it.
This put the 1 ohm resistor in line to the rest of the supply.
Reroute wire...problem solved.
The RT...and fault A1A5 -1,
the low pass filter board.
As expected, many relays were in need of cleaning as the self-test
failed on almost every bank. Although I had access to replacement
relays from a non-working A5 board, I decided to clean the relays
instead of replacing many with relays of unknown condition. I
removed one relay from the spare board and after some inspection
was able to remove the plastic cover from the relay using a
pointed end of a sharpened dental tool. Because the cover holds
the magnet in place, you have to reassemble the relay to work,
however, you can push the cover down until it ALMOST latches on
the plastic nibs in case you didn't get the relay clean enough.
After cleaning about 10 relays, the receiver passed the self test.
Although the picture below shows the relay off the board, you can
(and I recommend doing so) pull the cover off while the relay is
still on the board. It actually gives you some resistance to pry
(very carefully) the lower part of the notch away from the nib so
the cover can slide off. You'll need to do one side and then hold
the cover so it doesn't fall back into place while you do the
other side. With a little practice you can remove one in only a
few seconds. There may be some that are cemented to the circuit
board by coil dope but you can scrape that away from the base of
the relay. I haven't run across one that couldn't be cleaned on
the board. Clean the relay by carefully pressing the contacts
closed and pulling a plain piece of paper between them a few
times.
A1A6-1 Fault - Make sure you
have the antenna disconnected or it will fail due to changes in
the AGC voltage.
No power out from the
transmitter. Before I had the power supply back operational I had
attached an external 12 volt supply to the radio and had noticed
that I had no power out. I left that issue until after I got the
power supply back operational. Pulling the covers, it was apparent
why there wasn't any RF.
My first thought was that it
had been cut in depot due to a bad final section and that the
finals were bad. Luckily that wasn't the case and a new cable was
the last thing to complete the repairs. Again, don't be surprised
at what you might find!
The finished product!
UPDATE:
I had noticed that occasionally in SSB the
radio would 'freak out', probably due to the CPU resetting. Having
not tried it in CW, once I did, it was apparent there was a
malfunction somewhere. Power was very erratic, the CPU would reset
and the full BIT test wouldn't fail, but then wouldn't pass
either. It would get to then end of the test and then exit in CW
mode, unkeyed. The wattmeter showed good power during the test. I
tried an external power supply and it still continued to
malfunction. I swapped the TGC and final boards as I figured they
would have the most impact on power. I looked for RF problems,
cables worn, pinched, but couldn't find anything wrong. I finally
noticed there was a buzzing noise coming from the 13.6 supply
section in the power supply. Not sure where it was coming from, I
used the end of a turkey baster held to my ear and found it was
the output filter, which looks like a small transformer. Even
though the radio did not work with an external supply, I swapped
the entire power supply with my good one and the radio worked
fine. With an extra unit for parts, I swapped ALL parts on the
board only to find the problem was still there! I had originally
suspected the filter capacitors, but had swapped them with the
spares first thing. Let this be another lesson. Go with your gut
feelings. Turns out, the filter caps were bad. I replaced them
with junk box computer grade (although not of the same value) and
the radio is now (I hope) functioning normally. Transmitted signal
is clean. What is interesting is that there was no improvement
when using a GOOD external supply. Go figure.
Harris AM-7223 500 Watt
Auto Tune Amplifier
Dead. At least until I found
a poorly routed ribbon cable and unseated connector. The blue
ribbon cable behind the white cable had been routed, not through
the large slot designed for it, but sandwiched between the
aluminum partitions and the connector to the right of the photo
was not completely seated. After correcting those issues, the amp
powered up and passed the self-tests.
3CX800A7
Harris CU-2310 500 Watt Auto Antenna Coupler
(page last updated on
Thursday November 08, 2007)
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