The Heathkit HD-1410 Iambic keyer is a very popular unit. There are many of these still in use today. Although the keying paddles are not by any means a Brown Brother’s key paddle, they’re not too bad!

The HD-1410 features a built in power supply and adjustable sidetone. The side tone pitch is also adjustable, although you must open the case to access this control. The HD-1410 will operate on either 12 volt DC or 110 AC.

The output is fully solid state. The HD-1410 will key either grid block or cathode keyed transmitters.

All of this is housed in a small wrap around case that matches the "SB" line of Heathkit equipment.

Since the HD-1410 is fully solid state, a good place to start looking for trouble is the power supply. If the HD-1410 works on an external battery but not on AC, check the 110 AC fuse and the power transformer. On the other hand if the keyer seems dead, but the red power lamp comes on, check Q8 and D7. With a DVM, check the voltage on the collector of Q8. It should be at least 10 volts. The output, on the emitter, should be at least 5 volts. If the emitter is over five volts, then Q8 is shorted. If the output on the emitter is zero, then suspect Q8 or D7. Diode D7 biases the driver transistor on. The TTL IC chips in the HD-1410 require +5 volts to operate. Too much or too low of voltage will cause the HD-1410 to fail.

A common problem is a shorted or open output transistor. You can easily check this by turning up the sidetone volume. If the sidetone follows the keying, then the keyer is working, but the output transistors have failed. Check either Q5, Q6 or Q7. Also, check diodes D4 and D5. These parts fail if you try and key a transmitter the HD-1410 can not handle.

To get the HD-1410 to key most solid state transmitter, remove D5 and R27 and replace these with a jumper wires. This will allow the HD-1410 to pull the keying line to ground.

I've found IC3 can go bad and cause either a string of dots or dashes to be produced. Also check IC 5.

IC5 also drives the sidetone oscillator. Transistor Q3 takes the output from IC5 and drives the speaker.

After years of use, the paddles may need to be removed and cleaned. To remove the paddles, pull off the black plastic covers. Then, remove the speed and sidetone volume controls. Unsolder the wires from the pilot light. You can then pull down the front panel. There are a few screws holding the paddle assembly on the PC board. After removing the hardware, the paddles can be removed. Clean the contacts with a rough strip of paper.