Replacing the Band Switch on a Pilot Radiogram |
Written by Bryce Ringwood |
I guess we all make mistakes, but this one turned out to be very destructive. The radio was (and happily still is) a Pilot Radiogram, with four nondescript wires hanging out of the chassis. Two of the wires were for the mains connection and two were for the antenna and earth.
Sadly, someone chose the wrong pair. But then, because the radio didn't respond .. they turned the band change switch. The owner of the set blamed "kids". I think today's kids are far more savvy. I blame "adults".
This simple act burned out all the antenna coils and the antenna wafer on the switch. The antenna coil on the ferrite rod was missing - presumably someone brushed the charred remains away.
![]()
The contacts have melted and the rotor is cracked and burned
I contemplated the situation, then offered to install 4 antenna wires. The owner said " that would be ridiculous "(which it would) so I gave her a quote for a new switch (replacing the single burned out wafer wasn't an option, as the offending wafer was the "middlest" one.) Fortunately I had a switch kit. Note that you can purchase switch kits from electronic suppliers, such as RS electronics and Mantech. Each wafer costs well over R100-00 before you begin, so that the new switch can cost well over R1000-00.
There is an additional complication, in that the original switch was a custom-made item with front and back wafer contacts. These special wafers had to be simulated by adding additional wafers, where the original switch had five wafers, the new one had to have seven.
![]()
Original Band Switch
Since this won't be the first or last time a band-change switch needs replacement, here's one way of going about installing a replacement:
The final jobs were to check the AGC, refit the volume control/on off switch and fit a decent 3 core mains lead and plug.
![]()
New Band Switch
The turntable that came with the set had a modern stereo cartridge with no stylus. I used a new BSR stereo-compatible mono cartridge. This is a very loud radio, whether on GRAM or MW/SW. The sensitivity is about what you would expect from an ECH42 front-end, nevertheless there are plenty of stations to be heard on each of the shortwave bands.
The valve line-up is EZ41 (Rectifier), EL41(Output), EBC41 (Detector and AGC) , EF41 (IF Amplifier), ECH42 (Mixer/Osc) and an EBC41 doing something unknown. The magic-eye is the expensive EM34.
(To be edited)
|