[1000mp] Help!... VFO scan-down problem

[Pstark]

Pull the rubber band ring off the main tuning knob.
You will then see allen screw holding the main knob on.
loosten that allen screw.
pull the main knob off.
carefully observe the position and arrangement of springs and stuff for the
jog ring.
Observe the little slot that the jog control sits in.
carefully move the jog slot contol with a screwdriver or something.
All this can be done with the rig on.
Actually it must be on or you would have no idea what to do.
You will then see that the rig will stop scanning if you move the little
control one way or the other.
Fiddle with it till it stops.
It may be necessary to remove the springs and stuff.
and then replace everything.
To keep this from happening again, don't use shuttle knob.
At least dont use it to it's limit and then let it go.
It is not really a pain to do this. About 15 minutes will fix the problem.

Pete K4OM

-----Original Message-----
From: 1000mp-bounces at mailman.qth.net
[mailto:1000mp-bounces at mailman.qth.net]On Behalf Of Rod Elliott
Sent: Tuesday, September 25, 2007 2:46 PM
To: 1000mp at mailman.qth.net
Subject: [1000mp] Help!... VFO scan-down problem


I have a 3-year-old FT-1000MP MkV Field. It has
become unusable due to a very peculiar problem.
In short, the main VFO continuously scans down
the band at about 1 MHz per minute. If I let it
keep scanning,  it goes all the way down to
100KHz. The rig then resets itself to 7.000.00 MHz.

Transmitting stops the scan at whatever frequency
it was at when switched to TX. As long as it’s in
TX, it does not scan, but resumes scanning as
soon as switched back to RX. Makes it devilishly hard to work anybody
 hi!

This behavior first appeared several months ago,
shortly after the rig did a couple of spontaneous
memory resets for unknown reasons. At first, the
scanning behavior was intermittent and
short-lasting, starting and stopping
spontaneously. As time went by, these scans
became more frequent and lasted longer. Now it
scans all the time, starting as soon as I turn
the rig on. Nothing I’ve done with the controls
and memory settings, including a full CPU reset,
has fixed it. No further spontaneous resets though.

To research the problem, I read this reflector
going back several years and searched the VA3CR
FT-1000MP website. To summarize, this is a rare,
but not unknown problem. The causes fall into two categories:

1: RFI getting into the rig:
Not my problem
 the scanning happens when I am
not transmitting, and there are no nearby
transmitters. To ensure it’s not some unknown QRN
(like farmer’s electric fences, etc.) I clipped
ferrite chokes on all the leads in and out of the
rig and computer. No improvement.

2: Shuttle jog mechanism has a shifted center-point or shorted wire:
Could be
 discovered that I could pause the scan
by holding the jog ring about 10 degrees
clockwise. More clockwise it scans UP, less
clockwise it scans DOWN. Fine, but also
devilishly hard to operate holding the jog ring 


I have no idea how to get a look at the jog ring
mechanism. Even the FT-1000MP Technical
Supplement is silent on that. In any case, it’s
not certain my rig has mechanical problems in the
shuttle jog
 might also be an electrical fault in the scan circuitry.

The only mod in this rig is an INRAD roofing
filter board which was installed two years before the scan problem showed
up.

So
 a couple of questions for the MP gurus here...
1. Has anybody here had this problem and how did you fix it?
2. Can anybody offer a possible electrical diagnosis?
3. Anybody know how to take the VFO-A tuning
assembly apart to inspect the shuttle-jog mechanism?

All inputs welcome!  Many thanks in advance...

73
Rod Elliott  VE3UW


BTW, I have now worked around this problem by
buying a new FT-2000. Super rig
 a quantum leap
over the FT-1000 series! Still want to fix the Field and keep it as a
backup.


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