Tuesday, 13 October 2015

Inside the PF8

The first task with the boxed Pye PF8 was to open it up and inspect it for completeness. Inside these radios, which are incredibly compact for their age, considering there are no modern 'surface mount' devices, everything is hidden away under a screening plate. In typical Pye form, this plate allows access to all the adjustment points, and labels them very clearly

Removing the plate reveals the electronics. Great use is made of hybrid and thick film modules in Pye's compact handheld transceivers. Whilst in this state, I attempted to apply battery power and measure the voltage at the radio's input. In doing so I discovered the first issue that required attention - the corroded battery terminal.

The 'donor' set had a nice clean terminal, so the whole unit - terminal, insulator, spring and wiring, was removed from each and swapped over.

This time, the test revealed 1.19v at the radios battery input. Good, DC is now getting to the circuits. Rebuilding the radio, and inserting both batteries into the case, I turned on and gave it a go!

And got a very brief flash of the Tx light on PTT before the batteries, which probably havent seen a charger for a couple of decades, went flat! But - It did show the radio working, even if just for a moment!

Next step then is to get the batteries recharged, and to test the radio against the test set. This I can do using the bench PSU. Testing it might be the trickiest part. These radios use an internal skeleton plate antenna designed by Roger G3XBM, with no external antenna connector. To start with at least, testing will be indicative only, but at this stage all I really want to see is if it will receive, and if it transmits!

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