Heathkit power supplies

Rig power saupplies

I have two Heathkit HP23 power supplies, there were used with a number of heatkit transceivers and transmitters. One is an HP23A, the other is an HP23B version, not much difference between them. I have had to rebuild both, the original capacitors were past their use by date. I added current and voltage monitoring jacks and IEC power connectors, I do not like having long power chords dangling as I carry equipment, an accident waiting to happen.

These power supplies provide two switchable low tension voltage, 250@ 100 mA and 300 Volt @150 mA DC. The high tension voltage is 820 Volt no load and about 700 Volt @ 250 mA. The Bias voltage is minus 130 Volt at no load and about -100 Volt at 20 mA. The heater voltage is 12.6 Volt AC and max current is 5.5 Amp. The B version and perhaps some of the other version, did not seem to have the 6.3 Voltage tap brought out on the power socket.

The HP-23 family of Power Supplies for the SB-series started with the HP-23 in 1963. It was replaced by the HP-23A in 1968, which in turn was replaced by the HP-23B in 1973, which in turn was replaced by the HP-23C in 1978 and was produced until 1979. The Hewlett Packard Company did not let the Heath Company use HP as a designation for their products so the HP-23C then became PS-23. Even if these power supplies originally were meant for the SB-series they also became the standard power supply for the HW-100/HW-101.

These power supplies could stand aloan or be housed inside the SB600 external speaker cabinet. I have the following rigs that use these power supplies: HW-32, 20 Metre SSB transceiver, an SB-110, 6 Meter SSB transceiver and an SB101 SSB HF multi band transceiver. I have two power supplies and have collected the parts to scratch build another.

You will notice I have added six pin jacket sockets to each supply, the black socket is the Ground (-ve), two each of the red sockets are for measuring the two HT voltages and the supply current via a one Ohm resistor between the sockets and the fifth red socket is to measure the negative bias supply. To measure the voltages, measure btween the top pin jack socket on the appropriate site and to measure the current measure the voltage accross each pair of sockets. I have also added a "local" mains switch so I do not have to switch the supplies via the BIG multi way connectors that re used. Any cables I make will not have the power mains leads.

Universal Mains Power Supply

Some time ago I picked up an IP-32 high voltage mains supply at an AHARS Buy and Sell, I had been looking for one for several years. When I got it home and put it on the bench I soon discovered all was not well inside. The specifications say the High Voltage output is variable from zero to 400 Volt and maximum current is 100 mA (120 mA for a very short time). There is a zero to minus 100 Volt bias supply limited to 1 mAmp. Like the other power supplies above, the capacitors were well past their use by date and when I was testing I found I could not get any more than 300 Volt DC from of the HT supply. I soon discovered at least one BIG electrolytic capacitor was getting very hot so I turned it off before the power transformer suffered.With all the electrolytic capacitors replaced, all was good.

The valve (tube) line up is two 6L6 pass devices, a 6BH6 as the error amplifier, two OA 2's as the voltage stabilisers and a 6X4 as the bias supply.

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Written by and Copyright, Phil. Storr © Last updated 18th June 2019