GPO 332 - Transmitter / Receiver issues - UK Vintage Radio Repair and Restoration Discussion Forum

19Seventy7 · 3rd Nov 2022, 2:07 pm

Hi all

I recently got my hands on a GPO 332 which I’ve been doing some work on. The phone came to me with no transmitter in the handset, I have replaced this with a modern replacement designed for the 332.

Upon testing, the phone would ring and I could pick up and hear the other person, but they could not hear me. I found out that the handset wiring was “upside down” in that the red, green and white wires were flipped. Correcting this allowed the other person to hear me.

This is where one, possibly two, faults come in. The most irritating is that the other end repeats for the other user, so they can hear themselves again with a slight delay. I don’t hear the repetition.

The second is that with the correct wiring, the handset volume drops considerably, making it quite hard to hear the other person. I believe I have read that their sound quality isn’t as good as more modern phones (746 etc) but where I’ve had it louder and clearer, I wonder if it is a fault or not.

I will attach photos of the two wiring arrangements when I can, my phone isn’t complying right now!

Any suggestions appreciated

Thanks
‘77

3rd Nov 2022, 2:07 pm	#1
19Seventy7 Octode Join Date: Jun 2018 Location: Essex, UK. Posts: 1,307	GPO 332 - Transmitter / Receiver issues Hi all I recently got my hands on a GPO 332 which I’ve been doing some work on. The phone came to me with no transmitter in the handset, I have replaced this with a modern replacement designed for the 332. Upon testing, the phone would ring and I could pick up and hear the other person, but they could not hear me. I found out that the handset wiring was “upside down” in that the red, green and white wires were flipped. Correcting this allowed the other person to hear me. This is where one, possibly two, faults come in. The most irritating is that the other end repeats for the other user, so they can hear themselves again with a slight delay. I don’t hear the repetition. The second is that with the correct wiring, the handset volume drops considerably, making it quite hard to hear the other person. I believe I have read that their sound quality isn’t as good as more modern phones (746 etc) but where I’ve had it louder and clearer, I wonder if it is a fault or not. I will attach photos of the two wiring arrangements when I can, my phone isn’t complying right now! Any suggestions appreciated Thanks ‘77