[AMPS] Problem with Ameritron AL-82

[Bert Barry]

That's a good point Tom, but I suggest cleaning both the switch pins and the relay
pins as well as the swich contacts.   By a great coincidence, shortly after I posted
my note, my problem occurred again, after being OK for several months. (Last time I
simply reflowed the relay pins, and that worked, until now).  This time I measured
the resistance at the phono jack with key down and found it varied all over the
place, from a couple of ohms, up to 50 or 60, then back down to 15 to 20, as I
jiggled the phono plug.  I then took the bottom off and as soon as I touched the
relay (not the switch), the resistance dropped to less than an ohm.  I then sucked
the solder off the relay pins, resoldered, and resistance seems to be less than an
ohm, and doesn't vary while jiggling the phono plug.  But in view of your comments,
before putting the rig back together I'll clean and resolder the switch pins, and
spray contact cleaner on the switch contacts.  But my feeling is that it's the relay
pins that develop high resistance or open circuit from the vibration of relay
closures.

The only problem with this approach is that I'll never be sure which was the
culprit!
Mike, let us know how you make out, and your opinion.

Bert,  VE3QAA

Tom Rauch wrote:

> > I had exactly the same problem with my Alpha 87 driven by an FT-1000D.
> >  The problem was not the amplifier - it was a fault in the wiring to
> > the "tx-gnd" phono jack on the back of the FT-1000. Fortunately, at
> > least in my case, the problem was NOT in the FT-1000 tx-gnd relay,
> > which would have been a pig to replace.
>
> This makes me wonder.
>
> My FT1000D has dropped the switch lead a three times now, and
> while it was on the way out it did something similar to what Mike
> described except on many occasions it would NEVER close the
> amp relay.
>
> The first time I just barely touched the relay switch near the jack
> and it cured the problem. The second time (about a year later) I
> resoldered the connections on the switch, and it was OK for a
> week.
>
> The third time I cleaned the switch contacts, and it has been OK
> for almost a year now.
>
> I wonder if the switches aren't the problem, since mine would
> straighten out just by touching it or anything around it??
> 73, Tom W8JI
> W8JI@contesting.com



--
FAQ on WWW:               http://www.contesting.com/FAQ/amps
Submissions:              amps@contesting.com
Administrative requests:  amps-REQUEST@contesting.com
Problems:                 owner-amps@contesting.com