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TonyDuell · 25th Nov 2020, 5:40 pm

That 'red thing' looks like one version of the Transmitter 21A. That's an electronic unit using an electret microphone and an IC and is normally very reliable.

Can you measure the DC voltage between the 2 terminals on that Transmitter (with the telephone plugged into the line and off-hook)

Can you also post a photo of the insides of the main part of the telephone (the fixing screw for the cover is between the 2 cables at the back, it should be captive, just undo it until it springs out slightly and the cover is free). I want to see how different it is from a normal Telephone 746.

25th Nov 2020, 5:40 pm	#7
TonyDuell Dekatron Join Date: Jun 2015 Location: Biggin Hill, London, UK. Posts: 5,208	Re: TMA 7214 Faint outgoing speech That 'red thing' looks like one version of the Transmitter 21A. That's an electronic unit using an electret microphone and an IC and is normally very reliable. Can you measure the DC voltage between the 2 terminals on that Transmitter (with the telephone plugged into the line and off-hook) Can you also post a photo of the insides of the main part of the telephone (the fixing screw for the cover is between the 2 cables at the back, it should be captive, just undo it until it springs out slightly and the cover is free). I want to see how different it is from a normal Telephone 746.