From the manual:
|TUBES||6U8A Tunable Oscillator, Crystal Oscillator|
6AQ5A Output Amplifier
OA2 Voltage Regulator
|OUTPUT IMPEDANCE||5600 ohms shunted bu 100μμF cable capacitance|
|OUTPUT VOLTAGE||30V Nominal|
|STABILITY||Better than 500 cycles of set frequency over a one hour period (after 15-minute warmup)|
|POWER CONSUMPTION||30 watts at 117 volts (nomimal), 60 CPS, alternating current|
|DIMENSIONS (H x W x D)||5-5/8 inches x 7 inches x 9-1/32 inches|
|NET WEIGHT||7 pounds|
|SHIPPING WEIGHT||8-1/2 pounds|
I acquired my very clean Hallicrafters HA-5 at Hamvention 2016 to use with my Drake 2-NT CW transmitter, which I also had purchased at the 2016 Dayton Hamvention. The seller thought the VFO was functional but could give no concrete assurances.
After running my 2-NT "rock-bound" for several months, I finally decided to verify operation of the HA-5. My boat-anchor elmer, KB8TAD (link) was unavailable to help me with power-up and testing of the VFO. He did, however, send me instructions via email on how to construct and use a "dim bulb tester" in order to safely perform the inital power-up and tests.
Using a "dim bulb tester", I was able to confirm that the HA-5's built-in power supply was healthy and that the the VFO provides accurate and stable output on 80m, 40m, 20m, and 15m bands.
I've enjoyed using the HA-5 with the 2-NT for regular ragchew-QSOs on 80m and have used the pair on 40m and 80m during the Classic Exchange, during the Novice Rig Roundup, and for other QSOs. The HA-5 / 2-NT pair work beautifully together.
UPDATE 2017-02-27: I received only reports of a very nice note from my Drake 2-NT / Hallicrafters HA-5 during the Novice Rig Roundup 2017 event but during my very first rag-chew following the week-long event K8RAT reported a slight instability in my transmitted signal which he has taken to calling a "wooble". A switch to a known-good crystal confirmed that the 2-NT itself is healthy and that the problem is in the HA-5 or the connecting cables. I've been able to hear the instability myself while listening on the 2-C; it's not a classic chirp but an occasional warble in the transmitted tone. I will have to determine what is happening. Is it time for me to re-cap the HA-5? Do I need to check resistor values?
UPDATE 2017-04-27: While poking around inside the HA-5 to try to fix the "wooble" I discovered one of the two 0.01µF 1400-volt ceramic capacitors between the AC cord and chassis-ground was burnt-open. (Indeed, half of the capacitor was completely gone. (I suspect the VFO took a lightning strike while still in the station of a former owner.) At the recommendation of KB8TAD, I replaced the two-conductor AC cord with a three-conductor AC cord, adding a fuse on the hot side of the AC cord before the power switch, using the one good 1400-volt ceramic capacitor on the hot leg of the AC cord, and adding a 0.01µF 500-volt ceramic capacitor on the neutral leg of the AC cord. While testing the HA-5 after performing this modification, I found my VFO-Key cable to be intermittent at the RCA connector, so I made a new VFO-Key cable. I have not yet determined if either of these things fixed the "wooble" but until I can give the HA-5 a thorough test, I'm minimizing expectations.
UPDATE 2017-08-31: Periodic use of the Drake Novice station with the HA-5 VFO has disclosed that the power supply repairs did not fix the "wooble" problem. However, I have come to the conclusion that the "wooble" might be related to a dirty tuning capacitor wiper because making large excursions with the VFO seems to make the "wooble" go away. My next step will be to open the HA-5 and clean the capacitor, and while I'm poking around, I'll clean the bandswitch to see if this bring proper performance on the bands above 40m.
UPDATE 2017-11-22: After getting reports of a "buzzy" CW note, at the recommendation of KB8TAD, I verified the problem isn't a ground-loop issue and Rich gave me 22µF and 100µF electrolytic caps to replace the original multi-cap. When I opened the VFO to replace the caps, I found that a power resistor connected to the original 20µF cap wasn't soldered well. I re-soldered this connection and now need to get some signal reports so I can determine if I still need to replace the original caps.
UPDATE 2017-11-25: After installing the replacement 22µF and 100µF electrolytic caps in place of the original multi-cap—leaving the original cap in place for cosmetics—the "buzzy" CW note was replaced by a pure CW note.