[Hallicrafters] S meters

[Langston, Mike]

I'm a first-timer on the reflector, so be kind. I need some help.

1.	I have S-meters that won't zero (electrically, they're fine
mechanically). One is on a SX-115 and the other on a SX-117 (I also have a
similar problem on a 75-A4). I get action from both the "zero" pot and the
"factory gain" pot but they just won't get the meter low enough. The pots
have been checked and are correct. I suspect one or more shorted ceramic
caps in the AVC circuit and that will be the next thing I check (that would
make the AVC circuit inoperable, correct?).

2.	Once I have the S-meter operating properly, I will need to adjust
the factory gain to get an S-9 reading with the proper input signal. Without
a $1000 piece of test gear, is there any simple way to measure a 1/2 or 1
microvolt level? My signal generator (Sun Equip) has a variable output level
but how can I (reasonably accurately) determine what that is?

Everything else on these two rigs seems to be working properly. They have
been re-capped and tubes checked (replaced as necessary) but not yet
aligned. I also haven't checked the tube voltages against the manual in the
AVC circuit. I will do that when checking the ceramic disc caps in that
circuit. I'm currently working on the 117 and then will move to the 115.

Any ideas, tricks or comments would be greatly appreciated.

Tnx & 73
Mike Langston
KL7CD
mlangston at hcpriceco.com