[Heath] Trying to connect a SB 104 to a SB 200 -- need help/information

[JF]

Been quite a few years since I last used those. Are you aware that 
Heathkit made field upgrade kits for both the SB-104 (it became the 
SB-104A) and HP-1144? There were many changes, so you need to make 
sure which ones you have.

In case you someday may want to use the SB-200 with modern xcvrs (and 
this is also recommended for the SB-104 series) I would advise 
against using the original hookup, as the keying voltage and current 
required will almost certainly damage all but old radios rated for them.

For a few bucks you can make or buy a small low-voltage/current 
"soft-key" module that fits inside the SB-200 and replaces the old 
120VDC keying system. Back around the 1990's Allen Harbach WA4DRU 
started up Harbach Electronics, making available numerous kits/parts 
for the SB-104/SB-200, and one of these was the "SK-201 Soft-Key 
Keying Interface", still available for $30.00. Allen is now a SK, and 
the business was taken over by Jeff Weinberg, W8CQ

Description:
"The SK-201 safely acts as an amplifier interface to your modern 
transceiver to the Heathkit SB-200 or SB-201. This unit is mounted 
inside the amplifier and transforms the negative 120VDC key closure 
to approximately 0.7VDC at 1.5mA.  Without it you run the risk of 
severely damaging the keying circuit in your transceiver."

The website for SB-200 kits at Harbach Electronics is:

<https://harbachelectronics.com/product-category/heathkit-sb-200-sb-201/>

and the Soft-Key particulars are at:

<https://harbachelectronics.com/shop/heathkit-sb-200-sb-201/sk-201-soft-key-keying-interface/>

I would also highly recommend replacing the SB-200's power supply 
module/metering circuit, as the old ones deteriorated with age. For 
tips on restoring the SB-200 I would suggest looking at sites like

<http://www.crompton.com/hamradio/heath/sb200/sb200.html>

and numerous others.

73
John  KE5ZB


Original message:
On 6/17/2018 10:48 PM, A Lawrence Fibich wrote:
> Trying to connect the SB 104 to drive the SB 200 --- earlier told
> connect to pins 8 (relay) and pin 9 (ground) to go to turn on the SB
> 200. But in looking at the schematic and wiring diagram for the
> Heathkit power supply HP-1144 this isn't right-- e.g. pin 7 (GRN), 8
> (BLU), 9 (VIOL), 10 (no wire) are all tied together - and schematic
> for the power supply give no indication how it would work if even I
> separated the wires/connections.
> ? Anyone have a helpful clue-- interesting - like ALL other Heathkit
> transceivers give instructions on connecting the SB 200 -- ?? not
> this unit ??
> Thank you ALL in advance for all your helpfulness...
> Larry Fibich  AF6LF   Sacramento