11-04-2014, 07:48 PM
Hi all
I am restoring a Pye 25c and everything is fine except for the speaker. One of the coils was open circuit, but I got lucky as the break was very near the end of the winding and I was able to repair it. The total dc resistance measures 2k, which is correct.
However, I cannot get any sound from the speaker. I can see a nice strong audio signal on the o/p valve anode, so the speaker coil is fine and the voltages each side of it are correct (about a 6V dc drop across the coil).
Now comes the issue! I have no experience of these type of speakers whatsoever. I have cleaned all the parts and tried adjusting the big copper coloured screw that sticks out of the front, but nothing. There is a click from the speaker when I connect power to it. I assume that the long thin copper strip that has a thread connecting to the centre of the cone has to be adjusted very close to the the strip of metal with a slot in it underneath?? I've also heard people talk about a "reed". Is this the metal strip I have just referred to or another part that may be missing? Also, what is the purpose of the slot?
The magnet has some attraction if you hold a dscrewdriver near it, but I don't know if thats enough. Again, I have no experience of how to repair magnets, so I am stuck here.
Can anyone broaden my education on this type of speaker and suggest things I can try to get it working?
Any help very gratefully received.
Many thanks
Trev
I am restoring a Pye 25c and everything is fine except for the speaker. One of the coils was open circuit, but I got lucky as the break was very near the end of the winding and I was able to repair it. The total dc resistance measures 2k, which is correct.
However, I cannot get any sound from the speaker. I can see a nice strong audio signal on the o/p valve anode, so the speaker coil is fine and the voltages each side of it are correct (about a 6V dc drop across the coil).
Now comes the issue! I have no experience of these type of speakers whatsoever. I have cleaned all the parts and tried adjusting the big copper coloured screw that sticks out of the front, but nothing. There is a click from the speaker when I connect power to it. I assume that the long thin copper strip that has a thread connecting to the centre of the cone has to be adjusted very close to the the strip of metal with a slot in it underneath?? I've also heard people talk about a "reed". Is this the metal strip I have just referred to or another part that may be missing? Also, what is the purpose of the slot?
The magnet has some attraction if you hold a dscrewdriver near it, but I don't know if thats enough. Again, I have no experience of how to repair magnets, so I am stuck here.
Can anyone broaden my education on this type of speaker and suggest things I can try to get it working?
Any help very gratefully received.
Many thanks
Trev
