[1000mp] MP receive problem

Mon, 20 May 2002 21:32:36 +0000

At 20:13 5/20/2002 +0000, Garry Shapiro wrote:
>As Earl points out, below, my and his incidents were not band-specific. Now
>that the probelm has returened, hext time (if not in the middle of a pileup
>for a New One) I will try switching to Ant B and see if it is THAT relay.

My problem was band specific - 40M.  Using the Ant "B" port didn't help. An 
antenna on the ANT RX (external receive ant. port) bypasses both the LPF 
and HPF boards and this can narrow down somewhat to what boards the problem 
might be located.   This helped narrow my problem to the HPF board - as 
soon as I switch to the RX ANT the problem disappears.

>I have not checked by scrutinizing boards, but it is likely that one model
>of relay was used in many locations. It may well be that defective relays of
>this model account for the variants of the problem that are being reported.

Yep - at least on the HPF board the 8 relays are all Matsushita HD1-M-DC12V 
parts.  Anyone know of a small quantity supplier of Matsushita relays other 
than going to Yaesu?   I looked in my Mouser and Digi-Key catalogs and 
Matsushita wasn't listed in their relay product offerings.

73 Phil NA4M

>Garry, NI6T.
>
> > -----Original Message-----
> > From: [email protected]
> > [mailto:[email protected]]On Behalf Of [email protected]
> > Sent: Thursday, May 16, 2002 08:34
> > To: [email protected]; [email protected]
> > Subject: Re: [1000mp] MP receive problem
> >
> >
> > Phil, NA4M wrote:
> >
> > "When selecting 40m the received band noise & signals are barely audible
> > for a short time (varies but usually 1-2 minutes) before the receiver
> > seems to recover.   Selecting an antenna on ANT RX (external receive ant.
> >  port) results in normal receive levels."
> > ==========
> > I had a similar problem occasionally with my MP, but it wasn't
> > band-specific.  Garry, NI6T has also had the problem and I've heard
> > others complain about the same problem on this reflector.
> >
> > On my MP, it sounded like it might be a dirty antenna relay contact
> > somewhere in the radio.  Whenever it would happen, I would send a dit
> > with my paddle (or press/release PTT on SSB) and that would always
> > restore the signals to normal level.
> >
> > I also found that if I punched the ANT A/B pushbutton twice (or turn the
> > RX ant on/off) that would also restore the receiver to normal.  This
> > seemed to verify my "dirty antenna relay contact" theory.
> >
> > I haven't noticed the problem now for a couple of years (I've had my MP
> > now for 4 years), so after thousands of cycles it appears that the
> > offending contacts have wiped themselves clean.
> >
> > Garry, NI6T sent his MP into Yaesu for the problem while his radio was
> > still in warranty.  He said they told him they could not duplicate the
> > problem on the bench, but they replaced a few parts anyway (including one
> > or more relays).  Garry said that what they did seemed to alleviate the
> > problem for a while.
> >
> > 73, de Earl, K6SE
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Phil Duff NA4M     [email protected]   Georgetown, Texas  