BIAS Transformer T203, and Associated Circuitry

From Collins 30S-1 HF Amplifier
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new Hammond PWDP-13042 bias-supply replacement transformer

The replacement Peter Dahl transfomer! It took 2-1/2 months from initiating the order, until delivery. I made the actual purchase through Digi-Key, who provided the customer-facing fulfilment for Hammond. The transfomer also includes a 12.6VAC (at 800ma continuous commercial service) winding, which is used for three distinct purposes within the 30S-1:

  • the AC voltage from this winding powers the incandescent dial and meter bulbs
  • rectified and filtered DC runs through the HV-interlock circuit
  • rectified and filtered DC is used to operate the Antenna Relays (when an external short-to-ground occurs - often an Amp T/R relay inside the exciter)