[Heath] Fw: SB-102 S-Meter operation

[Kenneth G. Gordon]

On 27 Mar 2017 at 17:03, Joseph Smalley via Heath wrote:

>  Hello to the group.  I still use my SB-102 that I built in 1972,  I have two issues I want to fix.
> Number ONE is the poor operation of the S-meter very rarely does the S-meter give a good 
> reading
>
> Any ideas will be appreciated.

The "S" meter circuitry in the SB and HW series transceivers was changed several times until 
the LAST iteration of those changes happened for the late SB-102s. I had much the same 
issues as you do with my SB-102 and the last change made the difference. I don't have the 
info to hand at the moment, but maybe someone else here does.

> Number TWO sometimes the resting (idling) plate current will increase above the set value of 50 
> MA, this happens
> when I get long winded CW only here.

Normally, that is a clear indication of grid-emission from damaged or overheated final amp 
tubes. Screen voltage rises causing idle current to rise, especially after a long transmission. 
There was also a mod to modify the TR switch by moving one wire, such that the screens of 
the 6146s would be grounded when the rig was in receive, and that fixed that sort of problem.

Again, I don't have the exact info to hand at the moment, but some others may have here.

Ken W7EKB

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