I have a Heathkit SB-101 with matching speaker/power supply and one or
two other associated odds and ends that I'd like to get into the hands
of someone interested in restoring it. It actually seems to be in
decent shape. The major exception is that something is mechanically
limiting the VFO to about 200kHz rotation. Includes manual. I would
prefer to find a new or needy ham with enough technical background
that a bit of work on electronics isn't daunting. For such a person
in the Seattle area, the price will most certainly be right: come get
it. If I have to ship it, you'll pay shipping and something to
compensate me for packing it up.

k7itm -- msn -- com

I have a Heathkit SB-101 with matching speaker/power supply and one or
two other associated odds and ends that I'd like to get into the hands
of someone interested in restoring it. It actually seems to be in
decent shape. The major exception is that something is mechanically
limiting the VFO to about 200kHz rotation. Includes manual. I would
prefer to find a new or needy ham with enough technical background
that a bit of work on electronics isn't daunting. For such a person
in the Seattle area, the price will most certainly be right: come get
it. If I have to ship it, you'll pay shipping and something to
compensate me for packing it up.

k7itm -- msn -- com

Tom, I have a couple of those VFO's. I'd wager a buck to a doughnut that the
problem is the geneva wheel. There's a 5 turn one on the front of the shaft
and Heath lubricated it with something that turned to gum which welds
several of the wheels together. A drop of WD-40 or acetone or the like frees
it up so it acts like a Geneva wheel again. Clean it off and lube with some
good Moly and it'll never happen again.

Regards
W4ZCB

On May 5, 5:11 pm, "Harold E. Johnson" wrote:
I have a Heathkit SB-101 with matching speaker/power supply and one or
two other associated odds and ends that I'd like to get into the hands
of someone interested in restoring it. It actually seems to be in
decent shape. The major exception is that something is mechanically
limiting the VFO to about 200kHz rotation. Includes manual. I would
prefer to find a new or needy ham with enough technical background
that a bit of work on electronics isn't daunting. For such a person
in the Seattle area, the price will most certainly be right: come get
it. If I have to ship it, you'll pay shipping and something to
compensate me for packing it up.

k7itm -- msn -- com

Tom, I have a couple of those VFO's. I'd wager a buck to a doughnut that the
problem is the geneva wheel. There's a 5 turn one on the front of the shaft
and Heath lubricated it with something that turned to gum which welds
several of the wheels together. A drop of WD-40 or acetone or the like frees
it up so it acts like a Geneva wheel again. Clean it off and lube with some
good Moly and it'll never happen again.

Regards
W4ZCB

Thanks, Harold. That did the trick (some rather indiscriminantly
applied WD40), though I didn't see any easy way to get it far enough
apart to lube things. From the shaft position relative to the tuning
capacitor, I gather there's a worm drive in the VFO box, along with
whatever stop mechanism they used. I would have thought they'd just
use a stack of little washers with tabs on them, and not full-blown
Geneva wheels. I'm not too keen to spend the time to tear it down far
enough to get into the VFO box to properly re-lube things. I'll see
if I can get it into the hands of a new and/or needy ham--still would
like to find someone local (have one reasonable taker but that one
would involve shipping, which I'd prefer to avoid.)

Cheers,
Tom

K7ITM wrote:

Tom, I have a couple of those VFO's. I'd wager a buck to a doughnut that the
problem is the geneva wheel. There's a 5 turn one on the front of the shaft
and Heath lubricated it with something that turned to gum which welds
several of the wheels together. A drop of WD-40 or acetone or the like frees
it up so it acts like a Geneva wheel again. Clean it off and lube with some
good Moly and it'll never happen again.

Regards
W4ZCB

Thanks, Harold. That did the trick (some rather indiscriminantly
applied WD40), though I didn't see any easy way to get it far enough
apart to lube things. From the shaft position relative to the tuning
capacitor, I gather there's a worm drive in the VFO box, along with
whatever stop mechanism they used. I would have thought they'd just
use a stack of little washers with tabs on them, and not full-blown
Geneva wheels....

My recollection is it is just a stack of tabbed washers, and the grease
glues several of the washers together, thus limiting the number of turns
by an integral amount.

The difference between a Geneva wheel and this tabbed washer scheme is
lost on all but the watchmakers.

-Chuck

Note: A Geneva wheel is a Maltese cross like disk that interacts with
a wheel (gear) that has a single tooth. With each revolution, the single
toothed driving wheel engages the Geneva wheel to rotate one "cross arm".
When you get to the final revolution, the single tooth is blocked by a
section of the cross that hasn't been cut away.

The Geneva wheel was originally used in watches to limit the number of
turns the mainspring could be wound.