[Heathkit] coils for SB610 and SB620

[Jim Brannigan]

Further to the coil issue is the varactor diode.
I've been reluctant to experiment with the coils for fear of blowing the 
varactor diode.
Does anyone know the part#, value, parameters, etc. for this part?

Jim


> Okay.  For Mike and anybody else interested: I've done a little more 
> research and have come up with further info regarding the difference 
> between the coils in a SB-620 vs. those in a HO-13.  The "dummy" terminal 
> on the SB-620's coil *is* used as a solder tie-point, though it is *not* 
> connected to the coil itself.  The resistors which make up the 
> voltage-divider for the sweep-width switch are attached to it, as is the 
> lead to the switch itself.   The HO-13 coils (40-588 or -589) do not have 
> this "dummy" terminal, but are electrically identical to the 40-775 
> or -776, respectively, in the SB-620.  I *assume* they could be used to 
> replace these coils - you would just have to provide an isolated terminal 
> somewhere nearby as a substitute for the "dummy".  And it seems logical 
> that these coils from a SB-620 would be a drop-in replacement for the 
> corresponding ones in a HO-13.
>
> Of course, this is all based on the shaky premise that you can find any of 
> these coils in the first place.
>
> Oddly enough, my manual lists terminal lug #2 as the "dummy", but the 
> engineering blueprints list it as terminal #4.  Oh, well.
>
> FWIW, the coils for the HO-13 are 40-588 (455-1681 kHz.) and 40-589 
> (2075-3395 kHz.)..  The coils for the SB-620 are 40 -774 (not sure what 
> i.f. range, apparently replaced by the -808? or was it the -807?), -775 
> (455-1000 kHz), -776 (3000-3395 kHz.), -807 (5200-6000 kHz.), and -808 
> (1600-2445 kHz.).
>
> 73,
> Tom