What size fuse for Cessna Clock?

Does anyone know what size fuse is used in the clock circuit in a 172H.
This fuse is located in a holder by the battery box. POH only shows fuse
and no ampere rating. I would guess 1 or 2 amp??

Thanks,
Mark

Mark Martindale wrote:
Does anyone know what size fuse is used in the clock circuit in a 172H.
This fuse is located in a holder by the battery box. POH only shows fuse
and no ampere rating. I would guess 1 or 2 amp??

The last time I had to replace one, it was something ridiculous like a tenth of
an amp.

George Patterson
There's plenty of room for all of God's creatures. Right next to the
mashed potatoes.

My service manual for the C172, 1969 through 1976 models,
indicates in the electrical load anaylsis tables that the clock is
negligible. The smallest load listed in the table is 0.33 amps
so the clock is smaller than that. The manual does not provide
the fuse size as far as I can tell.

My guess would be 1/4 amp for the fuse.


"Mark Martindale" wrote in message
...
Does anyone know what size fuse is used in the clock circuit in a 172H.
This fuse is located in a holder by the battery box. POH only shows fuse
and no ampere rating. I would guess 1 or 2 amp??

Thanks,
Mark

I suggest 1 Amp as the OEM clock is an occasional very short but sharp
current pulse type of load. Certainly the wiring to the clock can take
1 amp without smoking anything but the fuse. If you put in a smaller
fuse, they may fail after a while.

Will you all please put this person in your "watch" before "kill" file.

This is absolutely bogus information.

Jim



"nrp" wrote in message
oups.com...
I suggest 1 Amp as the OEM clock is an occasional very short but sharp
current pulse type of load. Certainly the wiring to the clock can take
1 amp without smoking anything but the fuse. If you put in a smaller
fuse, they may fail after a while.

nrp wrote:
I suggest 1 Amp as the OEM clock is an occasional very short but sharp
current pulse type of load.

Say what? It's got a little motor in it. Current draw is constant.

George Patterson
There's plenty of room for all of God's creatures. Right next to the
mashed potatoes.

You must have a different clock than I have. Mine is the OEM (still
running after 30 years!) that has the rewinding clunk every 5 minutes
or so. Like they once used in cars 40 years ago.

"George Patterson" wrote in message
news:zxNee.56$Dn.52@trndny02...
nrp wrote:
I suggest 1 Amp as the OEM clock is an occasional very short but sharp
current pulse type of load.

Say what? It's got a little motor in it. Current draw is constant.

George Patterson
There's plenty of room for all of God's creatures. Right next to the
mashed potatoes.

I just replaced one of those fuses on a 172 from the sixties. It was under
the cowl, near the battery, something like 1 or 2 amps, and the POH stated
the fuse was for the clock. A new fuse never helped the clock to work,
though. It's still deader'n 4 o'clock.

Those old clocks are cute but don't last.

nrp wrote:
You must have a different clock than I have. Mine is the OEM (still
running after 30 years!) that has the rewinding clunk every 5 minutes
or so. Like they once used in cars 40 years ago.

Thanks for the replies. My clock is like nrp's and has the rewinding
solenoid that clunks about every 2 minutes. There is only a load on it
for a fraction of a second and is too fast to measure with my dmm. I am
going to put a 1 amp fuse in and see what happens.

Thanks,
Mark

Mark Martindale wrote:


Thanks for the replies. My clock is like nrp's and has the rewinding
solenoid that clunks about every 2 minutes. There is only a load on it
for a fraction of a second and is too fast to measure with my dmm. I am
going to put a 1 amp fuse in and see what happens.

Mark,

The Cessna part # for the fuse is an S1091-1. This is a 1 amp *rated*
fuse. The physical *size*, however, is a little different than your
standard automotive "AGC" glass fuse. The length is the same, but the
diameter is slightly larger. These are called "AGS", and if your local
NAPA doesn't have them, your local Cessna dealer will (they are pretty
inexpensive".

Happy Flying!
Scott Skylane
N92054