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

[Rod Elliott]

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.