[1000mp] Bad Antenna Relay? (long)

Fri, 17 Oct 2003 20:19:51 -0700 (PDT)

Bravo, I'm with you.  I can't even get a response from them.  Maybe it is time to look at a Pro II?

Garry Shapiro <[email protected]> wrote:Tod:

Your explanation is quite logical, and probably correct, both in the
electrical and political threads.

As I have stated, it is Yaesu's refusal to deal with this that bothers me as
much as or more than the problem itself. The MP was not a $50 accessory--a
modern high-end transceiver is a significant expenditure. One of the things
one expects from the vendor of a "quality" unit is that flaws, however
unintended and unanticipated, and however infrequent the occurrence--will be
dealt with.

It's called integrity.

Garry, NI6T

-----Original Message-----
From: [email protected]
[mailto:[email protected]]On Behalf Of Tod - MN
Sent: Friday, October 17, 2003 11:50 AM
To: [email protected]
Subject: RE: [1000mp] Bad Antenna Relay? (long)

In some cases if relay contacts never carry current (less than 1 ma) with
time "something happens" and they seem to develop a surface resistance that
acts to reduce the signal transmitted through them. I have a vague
recollection that by running a very small current (about 1 ma) through relay
contacts when they are closed the contacts will remain 'clean'.

In some respects this seems to describe some of the anecdotal data points
expressed on the reflector. If the contacts are mechanically burnished by
switching I suppose that the surface resistance might be cleared as well.

I have absolutely no idea how we would test this idea with our 1000MP's (or
variants thereof). I guess one would have to look at the circuit diagram and
figure out how to run a small current through the RX contacts without losing
signal. Since the error mode is not present in every MP, it may be that it
is a function of the type or lot number of the relays that were used in
production. It would not be the first time that a 'bad' lot of components
made its way into a production line. In fact, if it was not recognized that
a certain percentage of the components had attributes that caused RX
problems, the specifications for the component would remain the same and the
component would be used in many production runs. Since the problem occurs
very, very infrequently it would not be surprising if the relay
specification did not specifically deal with long term contact resistance.
Further, if the cost of specifying, testing and incorporating a different
relay was high enough to increase the product cost above a certain
threshold, the manufacturer might choose to make no change.

I suppose this is the ultimate horror story from a manufacturer and user's
point of view -- that the failure mode appears in only a small percentage of
the production units and that simplest cure seems to be to replace a single
component which resolves the problem in most cases. In a few cases one might
expect that a 'not entirely good' component is used to replace the original
'not entirely good' component and a few folks are in the position of the
simplest cure not being a cure for them.

My personal experience with Japanese and American manufacturers is that they
(or their lawyers) are loathe to declare that there are any flaws one of
their products. The may be willing to 'deal with a product that does not
perform the way they think it should' as long as they do not need to
publicly declare that they might need to make an engineering change.

I wonder if anyone else has the same assessment of the 'Bad Antenna
Problem'?

Tod, K�TO

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