On Sun, 7 Dec 2003 21:00:13 -0500, Ralph Mowery hath writ:

" Picked up a used IC-251A 2M all mode rig a few weeks ago. I left the
radio
on today and when I went back to it the evening, the display was blank and
by listening, it appeared that it could not be tuned. Turned rig off and
back on. No joy. Unplugged from wall outlet. Full joy! obviously the
rig
is partially powered up as long as it's plugged into the wall. Anybody
see
this problem before? If so, what was your fix. Don't really feel like
tearing into full blown troubleshooting. Guess I would start at the power
supply, but most likely trouble is in digital logic area somewhere, or
around CPU. Bummer. Hate when that happens...

While this probably does not have anything to do with your problem. The
Icom rigs of that series have a logic circuit that is running on a battery .

No, it does not. There is no battery in the IC-251/IC-551. (Hell,
these rigs were built before The Invention Of The Battery. HI!HI!)

On the back of the rig you'll find a slide switch just above the
fuse holder. Slide it to "OFF". As you guessed, there is an
small Always-On PS running -- when this switch is in the "ON" posn,
and it holds the memories across (front-of-the-rig) Power On/Power Off
cycles. My IC-551 exhibits the symptoms you describe. (My IC-251A
does not - yet.) As to why it doesn't work per factory spec's anymore --
my guess it's a combination of the small half-wave rectifier PS getting
ratty, plus the aging of the micro-processor (sic) chip, and the
number of direct hits by cosmic rays over the decades it's been in
service.

Since there are only 3 steenkin' memories in these rigs anyway, it's
No Big Loss to lose the memories. I simply leave both rigs on all the
time -- only unplugging them at times during ThunderStorm Season.
I use both rigs for weak signal SSB only. So, my memory "needs" are
trivial.

HTH
Jonesy
--
| Marvin L Jones | jonz | W3DHJ | OS/2
| Gunnison, Colorado | @ | Jonesy | linux __
| 7,703' -- 2,345m | config.com | DM68mn SK