![]() ![]() You'll also want to change the transmit/stby switch to close the ptt circuit. Other relay contacts can be used to mute the rx and ant changeover. Larger ones will cause the transmitter on lag on a bit before it completely dies causing terrific feedback. When you build the p/s keep your HV filter cap 20MFD or less. If your power transformer also supply's the heater voltage too you will want to use it to open the CT of the HV winding to kill the HV. The contacts on the relay are used to open primary of the plate transformer on the APS-50. The small trans is to power the relay coil thought the mic switch with a small dc voltage. The reason for that is the power cable is shielded with lot of AC wiring which may induce 60cy hum into ptt/mic a pic of one I did about 20yrs ago. On the APS-50 there is no connection to pin 8. FOR SALE Harvey Wells TBS-50D Bandmaster Deluxe Transmitter. On my sets I've rewired it the other way round so the audio is on the tip and the ring is the ptt line. HARVEY WELLS TBS-50D Bandmaster Deluxe Transmitter Parts or Restoration SN 4213 - 123.50. The ptt wiring is on pin 8 of the connector on the back and is connected to the tip of the mic connector on the front panel. Soon as I get you antenna back up I'll have one on the air. Was fixing an old Harvey- Wells Bandmaster Jr today and all the problems (for now) taken care of. I have worked a lot of CW DX with these fine boatanchors and Even. I've had a bunch of them and have repair a fair number too! Customers where always happy with the end product. My favorite offbeat rig is my Harvey Wells Bandmaster and Hallicrafters SX-71 receiver. Have found these little transmitters to be very reliable over the years. It may not be a bad idea to grab a spare set as it's not uncommon for the tank coils to be in bad shape or missing. If you read the manual the original loading cap requires a additional cap in parallel with it on 80 and 40mtrs. Work well on all bands.Īs I noted the replacement loading cap that was a common modification for these sets. It's useable on 80 on A3 but not so good on A1. Type: Amateur HF transmitter: Frequency range: 10-80 m: Mode: AM/CW: RF Power output: AM: 75 W CW: 90 W: Voltage: Mains: Current drain: Max A: Impedance: 50-500. If you are contemplating using it on HF w/the vfo you'll be chasing your contact up and down the band! The vfo is awful! Poor design lots of heat inside which causes it to drift badly. I uses it in my old grey one with a WWII T-17 carbon mike works great!!! You can play with the R/C values to change the fq response. I've used this circuit on the C to increase audio level to the modulator tubes. It's not uncommon to run into a C with the CMA-50 upgrade. You may have noticed that the front panels on the B and C models are a bit more deco looking, the D is a bit plainer. If weight is an issue then go for the B it's about 10pounds. Wasn't sure if you where looking for one to use or look at. ![]()
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