[Heath] SB-110A ? SOLVED

[Kenneth G. Gordon]

On 6 Apr 2012 at 10:08, George Babits wrote:

> Hi Ken,
> 
> Actually whoever installed the modification did such a good job it
> looked like part of the original kit.  What was throwing me was the
> "why" of the SB-102 schematic which showed the modification.  I didn't
> have the shorting plug  (for the PA screen) so  it was simpler to just
> remove the whole thing. Now if I can just figure out what those two
> loose leads behind the function switch were for.

If I am not mistaken, those are to switch the SB-640 external LMO into and 
out of the circuit. There should have also been a diode which connects two 
of the "ports" on that Molex connector together. I never did know what that 
was for, but suspect it may have been used as a "steering" diode in the final 
map screen circuit.

I also think that the reason the bit of SB-102 schematic was included with 
your rig was that the SB-102 came with that modification as part of the 
original kit.

If I remember correctly, very LATE models of the SB-101 also came from 
Heathkit with that modification included in the kit.

And as I said earlier, Heathkit sold a very small kit that enabled users of 
other SB/HW transceivers to install it so that an external LMO could be used 
with them. I have seen at least one HW-101 with that mod.

I have an SB-102 here which does have the Molex plug in it. If I can dig it 
out, I'll "reverse engineer" it to tell you what those two wires do, but it will 
take some time before I can get to it.

>  They are part of the
> wiring harness but I can't find them in the assembly instructions. 
> That'll keep me busy for a while today.

OK. Well, if you figure it out, let us know what you find.

vy 73, George.

Ken W7EKB