I designed a replacement PC board with new 120ufd 450VDC snap-in capacitors and new resistors to replace the original 125ufd 450vDC HV filter capacitors.
I designed this SB-400/401 LV replacement PC board with new snap-in capacitors and diodes.
I designed the PC board for a homebrew 100Khz calibrator. The circuit is a duplicate of the HRA-10-1 HR-10/10B receiver calibrator.
The homebrew 100Khz calibrator is mounted in an HR-10B receiver. Power for the calibrator is taken from the octal socket terminals below the chassis (3 wires fed through the octal socket guide post hole)). This arrangement allows the calibrator to be controlled by the original front panel slide switch.
HW-100 and HW-101 LMOs
There are differences in the 2 LMOs. For example, the HW-100 LMO on the left will not work in an HW-101 nor will an HW-101 LMO on the right work in an HW-100.
The LMO tube is NOT the oscillator but rather it’s a “Buffer Amp”. The oscillator is solid-state MPF-105 FET. Both LMO frequency ranges are the same, 5.5 MHz at the bottom of ALL bands and 5.0 MHz at the top of ALL bands.
The LMO tuning ranges do not change when the band changes like some older VFOs do (HG-10, VF1, etc).
The LMOs are used in both RX and TX. A failed LMO will result in the loss of both RX and TX.
Original (top) HW-101 VFO planetary ball sides and new HW-101 VFO Planetary ball drives (bottom). The ball drives were made by Oren Elliott Products INC in Ohio.
Fully rebuilt HR-10B. The receiver was disassembled to a bare chassis. All resistors and fixed capacitors were replaced, All point to point wire was replaced and reassembled to operational condition.
Apache TX-1 (Left Mohawk RX-1 (Right) non amplified D-104. PTT change made to the transmitter with 4PDT 6VDC relay powered by internal 5VDC regulated power supply in the bottom rear of the Apache..All-solid-state GR-78 six-band short wave receiver. The power source is a chargeable battery pack. I removed the 120VAC charger circuit. The battery pack has lasted for over 2 years. the receiver works rather well with the simple extendable vertical antenna. An outside antenna increases the reception.
Marauder HX-10 AM/CW/SSB VFO controlled transmitter. This model was the last of Heathkit’s “BIG” ham receivers and transmitters. AM power is 25W while SSB is 100 watts peak and CW is 100 watts. The HX-10 didn’t work when I got it. I had to replace the final amplifier’s screen resistor. I also replaced all of the filter capacitors. It works rather well now.
Regulated HV and LV power supplies. The frequency counter (top right) is an all-solid-state Opto 8000 512Mhz counter.Fully rebuilt IM-18 VTVM. Disassembled to a bare chassis, replacing point-to-point wiring, and all resistors on the PC board, then restored the cabinet with Rustoleum Nutmeg paint.
Various solid-state Voltmeters and VTVMs.
More vintage VTVM. The top left is an Eico fully rebuilt Eico 145A Signal Tracer. To the right of the Eico 145A is a vintage Heathkit 1949 V4 VTVM. The bottom left is an IG-102 RF signal generator. They ALL work. The bottom picture shows my homemade RF Probe is made out of 1/2″ diameter PVC pipe and 2 end caps, 3 1N5711 diodes, a 4Meg resistor, a 1KVDC 0.001ufd capacitor, a “tip” from a Velleman TLM6 plastic probe, 1/4″ mono plug, and RG174 coax cable.
