[1000mp] RELAY INFO

[Garry Shapiro]

Cecil:

Good work, but for my money, as your logic indicates, the T/R relay is the
culprit. I believe that, while experiencing attenuation, I have switched
antennas A/B and back and it is not that relay. The T/R relay is the only
one being toggled when the condition appears. Also, I do not believe
lightning is the major causative factor. I live in an area (coastal W6) with
extremely low lightning incidence, and am down in a canyon as well.

The difficulty in performing the tap test is one must first induce the
failure condition. Depending upon how often the condition occurs, that could
be time-consuming, indeed.

Garry, NI6T

-----Original Message-----
From: 1000mp-bounces at mailman.qth.net
[mailto:1000mp-bounces at mailman.qth.net]On Behalf Of Cecil Acuff
Sent: Tuesday, September 05, 2006 9:51 AM
To: All about Yaesu 1000mp
Subject: [1000mp] RELAY INFO


Bob and Group,

    I have complete documentation on the MP but not the MK V.  There
probably is not a lot of difference in that section but I may be wrong.  I
find five relays in the receive path that could cause problems:

RL8701 P/N AG2013 used as Antenna A select relay.  There is an identical
relay used as Antenna B select relay. (RL8701) A nearby lightning strike or
static charge on the antenna system could have damaged the contacts in the
Antenna A relay.  One test would be to connect your antenna system to the
Antenna B input on the rear and select antenna B for a while and see if
problems continue....or the next time it fails operate the ANT A/B switch
several times and see if it restores receive sensitivity.  These are located
on the ANT-UNIT.  This is the first relay exposed to the antenna system so
it might be the culprit but it's not switched a lot so I would more suspect
the next relay in my list....

RL6016 P/N AE5343 used as the T/R switch and located on the LPF-UNIT.  This
operates every time the PTT is operated and would be my main suspect.

RL1001 P/N AGY2323 used as the RX antenna switch.  Like the first two not
operated often so down on my list of suspects but certainly possible.  As a
test next time it fails operate the ANT RX button a few times and see if it
restores receiver sensitivity.  This relay is located on the RF UNIT.

RL1003 and RL1002 both used to switch in 6db and 12db of attenuation
respectively.  Combined gives you the 18db.  Could make the receiver appear
to drop in sensitivity by 6 or 12 db but I wouldn't expect 18 because that
would require failure of contacts in both relays at the same time which is
not likely.  A test would be to switch the attenuator switch through it's
full range a couple of times the next time it fails and see if that restores
receiver sensitivity.  These relays are located on the RF UNIT.

Another thing I would do would be to operate the radio with the cover
removed and tap lightly on these relays when in failure mode and see if you
can isolate the culprit that way...

Use an insulated tool handle or such.

My #1 guess would be the T/R switch.

I don't think the relays are anything proprietary and replacements should be
easy to locate.  I know one manufacturer, Omron, makes a range of relays
that might fit the need...I would look in the Allied or Mouser catalogs for
replacements.

Hope that helps a bit....again if the MKV is completely different sorry for
any confusion...so far I have not had relay problems in my early MP.

Cecil Acuff
WB5VCE

----- Original Message -----
From: "Bob Scott" <w4zy at bobandpenny.us>
To: "All about Yaesu 1000mp" <1000mp at mailman.qth.net>
Sent: Tuesday, September 05, 2006 8:10 AM
Subject: Re: [1000mp] Relay thing..deaf receiver


>I keep reading this thread in hopes of obtaining more information about the
>relay issue.
> 73,
> Bob
> W4ZY
> ______________________________________________________________
> 1000mp mailing list
> Home: http://mailman.qth.net/mailman/listinfo/1000mp
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