[ICOM] TX Problem IC970A 2.4 GHZ module

[Gary]

On Johnny's recommendation I am trying again via the email address he supplied. I
am continually hopeful for a helpful reply from Icom. There are many IC-970's
still in service and some users are enjoying the various optional band units
although they are rare. I've always thought of the 970 as a radio ahead of it's
time and I wish Icom had stuck with it a bit longer so more information, manuals,
parts, options, etc. would be available. I'm told the band units can still be
occasionally found in Asia but I've not been able to confirm. The only
shortcoming I can think of is that they didn't offer more optional transceiver
units, i.e., 220Mhz, 50Mhz, or 902Mhz. Most of these bands though are specific to
the U.S. and not other markets. Finding the UX-98, UXR-96, or another UX-97 would
be great but having the technical info (schematics, etc.) would be even better
right now. Before someone asks, no, Icom did not include the optional band units
in the IC-970A/E/H service manual.
73,
Gary

STeve Andre' wrote:

> Thats really weird.  I'm not doubting you, but I talked with someone
> at Dayton last year who had a problem with an ic-1201 rig, the
> Japanese version, and he called them, and after a little comic
> confusion of English manglement, he was able to ask his question
> and got something in the mail later.
>
> I've never talked with them, but I have heard they're very
> helpful.  I can only suggest trying again?
>
> --STeve Andre'
> wb8wsf
>
> On Tuesday 01 March 2005 23:58, Gary wrote:
> > yes, repeatedly but they would not reply.
> > Gary
> >
> > STeve Andre' wrote:
> > > I'm curious: have either of you contacted Icom in Japan about these
> > > problems?
> > >
> > > --STeve Andre'
> > > wb8wsf
> > >
> > > On Tuesday 01 March 2005 22:54, Gary wrote:
> > > > I have this problem with my 1.2Ghz module. I'm still troubleshooting
> > > > but it's looking like a bad PA module. The effort is a major pain
> > > > without a schematic. I've asked for a schematic copy from every forum I
> > > > could find but nobody replied. Not even Icom America or Scott Malcolm
> > > > had literature on the 970 option modules. Doug is the first in my
> > > > experience to even admit to having one of the 2.4Ghz modules, I hope he
> > > > has literature to go with it. Good luck Doug. Gary
> > > >
> > > > "NICK.WALLACE" wrote:
> > > > > Hi All,
> > > > >
> > > > > I am posting this on behalf of Doug VK4OE. We were wondering if
> > > > > anybody else had encountered the same problem which is as follows. I
> > > > > will pass any info received onto him.
> > > > >
> > > > > Thanks in anticipation.
> > > > >
> > > > > Nick   ZL1IU
> > > > >
> > > > > >From Doug.....
> > > > >
> > > > > Just to save you some typing, I'll describe again what I am
> > > > > experiencing, which only relates to the 2.4 GHz module in transmit
> > > > > mode....the other features of this excellent radio are currently
> > > > > working well.
> > > > >
> > > > > The problem is one of "fading" transmitter power as something
> > > > > obviously is heating up in the 2.4 GHz transmit path.  The scenario
> > > > > is that the radio has been switched off for a time long enough for it
> > > > > to cool to room temperature internally, then it is powered up and
> > > > > switched to 2.4 GHz transmit mode (continuous, e.g. FM).  The RF
> > > > > output control is set to maximum.
> > > > >
> > > > > It transmits the full 1 Watt for 2 to 3 minutes (or 5 minutes if
> > > > > ambient temperature is cooler) then, over a period of about a minute,
> > > > > the transmitter power gradually falls away to around 50 mW.  Whilst
> > > > > this is happening the ALC gradually climbs to a high level.
> > > > >
> > > > > Momentarily switching to RX or switching the whole radio off briefly
> > > > > then on again do not lead to a return to 1 W output.  Only powering
> > > > > off and letting the whole radio cool for an hour or so leads to a
> > > > > return to 1 W output, and being ready for the whole fault sequence to
> > > > > occur again.
> > > > >
> > > > > It is conjectured that there is something wrong with one or more
> > > > > component in the RF path between the TX amplifier and the antenna
> > > > > connector, something which is thermally active.  Has anyone else had
> > > > > a similar problem and found the solution?
> > > > >
> > > > > Thank you
> > > > >
> > > > > ----
> > > > > Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net
> > > > > Icom Users Net: Sundays, 1700Z, 14.316 MHz
> > > > > Icom FAQ: http://www.qsl.net/icom/
> > > >
> > > > ----
> > > > Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net
> > > > Icom Users Net: Sundays, 1700Z, 14.316 MHz
> > > > Icom FAQ: http://www.qsl.net/icom/
> ----
> Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net
> Icom Users Net: Sundays, 1700Z, 14.316 MHz
> Icom FAQ: http://www.qsl.net/icom/