Heathkit SB 200

[k0ayf]

I have a SB 200 with the Harbach soft key installed and will not work with my SB101 but will work with any other modern rig such as a ICOM 7000. The TR relay in the SB 200 just will not energize, there seems to be no problems in the SB 101. Any help?

Mike / K0AYF

[Pete, WA2CWA]

What connections are you making to the SB-101 to key the SB-200?

[KA8WTK]

  If I remember right, the SB-200 uses 120 volts to operate the relay. Your SB-101 would ground this voltage with an internal relay contact to operate the relay in the SB-200. A modern rig would "smoke" in an instant trying to do that. The Soft Key unit allows the lower voltage and current available from a modern rig to throw a relay on the Soft Key board that connects the 120 volts to ground and close the relay in the SB-200. The SB-101 does not supply the low voltage to operate the Soft Key board relay that your IC-7000 does.
  You would need to consult all three schematics to see if my memory is correct before making any changes.

  Someone please correct me if I am not remembering correctly!

Bill

[WQ9E]

Bill,

I think you are on the right track except even the modern rigs don't supply a voltage; just the relay contacts to control the low voltage supplied by the soft key circuit which then keys the existing AC coil relay in the SB-200.

But I wonder if the problem is the relay contact on the SB-102 has enough resistance that the low voltage circuit isn't working with it; perhaps a relay contact cleaning is in order.  I would use an ohm meter to measure the closed relay resistance of your transceiver and see what it shows.

[Pete, WA2CWA]

  If I remember right, the SB-200 uses 120 volts to operate the relay. Your SB-101 would ground this voltage with an internal relay contact to operate the relay in the SB-200. A modern rig would "smoke" in an instant trying to do that. The Soft Key unit allows the lower voltage and current available from a modern rig to throw a relay on the Soft Key board that connects the 120 volts to ground and close the relay in the SB-200. The SB-101 does not supply the low voltage to operate the Soft Key board relay that your IC-7000 does.
  You would need to consult all three schematics to see if my memory is correct before making any changes.

  Someone please correct me if I am not remembering correctly!

Bill

There is no relay on the soft key board. With the soft key wired in place in the SB-200, to activate the Internal SB-200 relay generally requires a ground or close to zero volt potential on the antenna relay jack of the SB-200.

[KM1H]

The SB-200 uses a negative -125V supply for the relay line and that is what is brought to ground at the relay connector.  The Harbach kit changes that to a  low voltage and current. Most modern rigs use a SS switch to ground the amp control, older and slower ones used a relay.

The SB-101 relay contacts may have pitting and a high enough resistance to have any effect at the new low voltage. Try cleaning them.

Carl
KM1H

[k0ayf]

I have a SB 200 with the Harbach soft key installed and will not work with my SB101 but will work with any other modern rig such as a ICOM 7000. The TR relay in the SB 200 just will not energize, there seems to be no problems in the SB 101. Any help?

Mike / K0AYF

Thanks for the quick reply's I have done all the things mentioned, traced all the wiring in the 101, cleaned the contracts in the 101, relay functions as it should, contacted Harbach he says it should work. We'll keep at it.

Thanks, Mike /K0AYF

[Pete, WA2CWA]

I have a SB 200 with the Harbach soft key installed and will not work with my SB101 but will work with any other modern rig such as a ICOM 7000. The TR relay in the SB 200 just will not energize, there seems to be no problems in the SB 101. Any help?

Mike / K0AYF

Thanks for the quick reply's I have done all the things mentioned, traced all the wiring in the 101, cleaned the contracts in the 101, relay functions as it should, contacted Harbach he says it should work. We'll keep at it.

Thanks, Mike /K0AYF

One side of a SB-101 relay contact goes to the center connection of the antenna relay jack on the SB-200. The other side of the relay contact in the SB-101 should go to the ground/chassis connection. When you key the SB-101, the relay in the SB-101 should close these two contacts (make connection to each other) and key the SB-200.