Icom 730 preventative maintenance question
Michael Brown
though I have had my Extra class license for about 2 years now. I noticed
on the Icom web page that there are several preventative maintence tasks
that they recommend performing on the IC-730 due to the age of these rigs.
I am looking for anyone that may have performed these tasks on the IC-730
that might be able to give me a basis walk-through of how I need to go about
taking the panels off the radio to gain access to the RF unit in the radio.
Here is what is listed on the Icom web page that they reccomend doing to the
radio:
1.) On the RF unit, resolder the J2 and J3 connectors. Due to the
relatively thick coax cables on the connectors, these solder joints tend to
crack with age and cause intermittent transmit and receive problems.
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2.) Make sure the receiver preamp works. If inoperative, replace relay
RL1 on the RF unit. Install the factory update to prevent relay failure.
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3.) Check transistor Q5 on the RF unit. If it is a 2SC945Q, replace it
with the improved 2SC2878B to prevent spurious output from the transmitter
and failure of the driver transistors. If Q5 is a type 1636, it doesn't need
to be replaced.
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4.) Clean the RIT pot and switch with tuner cleaner. These controls
are usually noisy and erratic, making the RIT hard to use.
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5.) Tighten the chrome-plated PC board mounting screws. The screws and
spacers tend to come loose if the radio is used in a high-vibration, mobile
environment. Don't forget to tighten the screws on the logic and IF units
located beneath the main unit.
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6.) Check the bandwidth coupler for proper tightness.
Tighten as needed.
I'm sure the first step of re-soldering the J2 and J3 connectors on
the RF unit I can probably handle if all this involves is desoldering the
connectors and resoldering them. I'm not so much concerned about the
receiver preamp working, but does anyone know if Icom still stocks parts for
the Icom 730? The third step reccomends swapping out the Q5 transistor on
the RF unit if it is a 2SC945Q transistor and replacing it with a 2SC2878B
transistor to prevent spurious output from the transmitter and failure of
the driver transistors. How hard would it be to replace this transistor? I
would assume it would involve desoldering the transistor and replacing it
with the new transistor. Would I just need to get a 2SC2878B transistor and
some heat sink compond to replace this transistor? Where would get the
2SC2878B transitor? Can I order one for Mouser, or would this have to be
ordered directly from Icom? Step 4 involves cleaning the RIT pot with some
tuner cleaner, probably the easiest step. How do I locate the RIT borad to
clean the pots? I would assume here too that all I need to do is to spray a
shot of contact cleaner in the holes of the pot and switch on the RIT unit?
Step 5 reccomends tightening all of the screws on the PC board. Hopefully I
can handle this step if I can get access to all of the srews to tighten
them. Step 6 reccomend checking the bandwith coupler for proper tightness
and retightening it if needed. Where is the bandwidth coupler located
inside the radio? What tools would I need to tighten it?
I thought I would post these questions on the newsgroups to see if
anyone that is a little more technical-minded than me could walk me through
performing these tasks. I have downloaded an instruction manual and service
manual for the IC-730, but I thought maybe someone who might have a 730 and
has performed these tasks could tell me how do them a little easier. The
last thing I want to do is screw up a good radio. Thanks for reading my
long post. Please e-mail me if anyone can help me out with this. Thanks!
73,
Mike KU4UV
Lexington, KY.
Bob Miller
wrote:
I would say, fix things only after they break. You'll go a little
balmy trying all the preventatives you suggest. Since you have a
service manual, that should give you what you need to walk you through
the procedures.
Parts on a rig that old are iffy. Icom may have some. And not have
some. Manufacturers are required to stock parts for only 7 years.
Finally, as the owner of an Icom 735, which is about the same vintage
as your 730, I can recommend Clif Holland at Avvid in Irving, Texas to
fix what you cannot.
Have fun...
Bob
k5qwg
>I recently purchased an Icom 730 HF radio. ... ... The
Gary P. Fiber
wrote:
>I recently purchased an Icom 730 HF radio. This is my first HF rig evn
Those are not really preventive maintenance issues but troubles and
cures if the rig exhibits them. I would not do anything until you have
any of htose listed troubles, if you do at all.
The IC-730 only meets receiving specifications when the pre amp is
operating. I owned a 730 for several years with any problems except
for the pre amp relay. You will like the 730 its a nice rig.
Gary K8IZ
Washington State Resident
Registered Linux User # 312991