Transistor Radio Problem
Discussion
ked.
LunarOne said:
In what way? If it was working before the switch went kaput, then it ought to work again. Unless you fixed it with a sledghammer...?
It does nowt. The switch appears to work in the same way, and I've tested all the continuities. I had to reattach a speaker wire, but when I switch it on, there's no sound, not even a crackle.I've done all the circuit testing I can, so the next step is to reinstall the old switch, and see if I can recreate the fault, in which case I know the new component is at fault.
That original switch looked like a combined potentiometer and switch. The 3 smaller terminals are the potentiometer (also known as variable resistor), the two larger terminals are the power switch. Did you replace the original switch with another with 5 terminals, or did your just attach something to the 2 power terminals? The symptoms you described originally all point to that combined pot / switch, so if it worked before my guess would be that you've wired up the new switch wrongly.
Mave said:
That original switch looked like a combined potentiometer and switch. The 3 smaller terminals are the potentiometer (also known as variable resistor), the two larger terminals are the power switch. Did you replace the original switch with another with 5 terminals, or did your just attach something to the 2 power terminals? The symptoms you described originally all point to that combined pot / switch, so if it worked before my guess would be that you've wired up the new switch wrongly.
The replacement was identical (but maybe 2mm smaller in diameter). I assumed the five pins do the same thing in each case.Yeah, should do. If you've tested continuity then I guess you've got a multimeter?
I doubt that the new pot/switch is at fault, but if you want to check it - (sorry if I'm teaching you to sick eggs!)
The 2 big terminals either side of the cam are for power - should have infinite resistance when the switch is off, very low resistance as soon as the switch is clicked on with no further change as you rotate it to max volume.
The 3 smaller terminals are for the potentiometer. I'm guessing you have the centre and maybe one other connected. You should have 10k resistance across the outer 2.
If you put your meter across the centre and 1 of the outers it should vary from zero to 10k as you rotate the knob. If you put your meter across the centre and other outer it should also vary from zero to 10k but in the opposite direction.
Have you got a photo of the original installation, and the current installation?
I doubt that the new pot/switch is at fault, but if you want to check it - (sorry if I'm teaching you to sick eggs!)
The 2 big terminals either side of the cam are for power - should have infinite resistance when the switch is off, very low resistance as soon as the switch is clicked on with no further change as you rotate it to max volume.
The 3 smaller terminals are for the potentiometer. I'm guessing you have the centre and maybe one other connected. You should have 10k resistance across the outer 2.
If you put your meter across the centre and 1 of the outers it should vary from zero to 10k as you rotate the knob. If you put your meter across the centre and other outer it should also vary from zero to 10k but in the opposite direction.
Have you got a photo of the original installation, and the current installation?
Many years ago when 'That's Life' was on BBC TV, a pensioner wrote to the programme, as her radio from Radio Rentals had packed up. Many years previously Radio Rentals had told her she could keep the radio for no further payment, but they were no longer able to service it. Anyway, 'That's Life' contacted the British Radio Society or whatever it was called, and one of their members who collected old radio receivers, made a replacement coil to repair it.
The Radio Society of Great Britain (RSGB) may be able to help point you in the direction of someone with the necessary skills, as many of their members build equipment as well as using off the shelf transceivers for competitions.
Another option may be to take the radio to a 'Repair Cafe' when such things are allowed to re-open. If you are in luck they may have someone with electronics fault finding skills.
The Radio Society of Great Britain (RSGB) may be able to help point you in the direction of someone with the necessary skills, as many of their members build equipment as well as using off the shelf transceivers for competitions.
Another option may be to take the radio to a 'Repair Cafe' when such things are allowed to re-open. If you are in luck they may have someone with electronics fault finding skills.
Mave said:
Yeah, should do. If you've tested continuity then I guess you've got a multimeter?
I doubt that the new pot/switch is at fault, but if you want to check it - (sorry if I'm teaching you to sick eggs!)
The 2 big terminals either side of the cam are for power - should have infinite resistance when the switch is off, very low resistance as soon as the switch is clicked on with no further change as you rotate it to max volume.
The 3 smaller terminals are for the potentiometer. I'm guessing you have the centre and maybe one other connected. You should have 10k resistance across the outer 2.
If you put your meter across the centre and 1 of the outers it should vary from zero to 10k as you rotate the knob. If you put your meter across the centre and other outer it should also vary from zero to 10k but in the opposite direction.
Have you got a photo of the original installation, and the current installation?
Useful info, thank you. No photo of the origonal installation, no.I doubt that the new pot/switch is at fault, but if you want to check it - (sorry if I'm teaching you to sick eggs!)
The 2 big terminals either side of the cam are for power - should have infinite resistance when the switch is off, very low resistance as soon as the switch is clicked on with no further change as you rotate it to max volume.
The 3 smaller terminals are for the potentiometer. I'm guessing you have the centre and maybe one other connected. You should have 10k resistance across the outer 2.
If you put your meter across the centre and 1 of the outers it should vary from zero to 10k as you rotate the knob. If you put your meter across the centre and other outer it should also vary from zero to 10k but in the opposite direction.
Have you got a photo of the original installation, and the current installation?
Start by identifying the radio and getting the circuit diagram
http://www.kbmuseum.org.uk/reg_rgd.htm
http://www.kbmuseum.org.uk/reg_rgd.htm
Doofus said:
Useful info, thank you. No photo of the origonal installation, no.
Few other checks to do with the switch installed - With no batteries fitted, measure the resistance from the centre switch terminal to the speaker terminal. You should see the resistance go up and down by 10K of you sweep the knob from end to end.
With batteries fitted, one of the big terminals should always have 9v on it. The other should go from 0v to 9v when you turn the switch on.
Edited by Mave on Thursday 4th March 15:51
NMNeil said:
Start by identifying the radio and getting the circuit diagram
http://www.kbmuseum.org.uk/reg_rgd.htm
Useful site.http://www.kbmuseum.org.uk/reg_rgd.htm
Looks like an R160 from the earlier photo.
OP double check your speaker wires and battery wires to make sure they are properly connected.
ETA - I see a DC power jack on the rear? Also check wires to/from this and it’s condition. Any issues here will result in a dead set.
Edited by LordLoveLength on Thursday 4th March 15:45
LordLoveLength said:
NMNeil said:
Start by identifying the radio and getting the circuit diagram
http://www.kbmuseum.org.uk/reg_rgd.htm
Useful site.http://www.kbmuseum.org.uk/reg_rgd.htm
Looks like an R160 from the earlier photo.
OP double check your speaker wires and battery wires to make sure they are properly connected.
ETA - I see a DC power jack on the rear? Also check wires to/from this and it’s condition. Any issues here will result in a dead set.
Edited by LordLoveLength on Thursday 4th March 15:45
Thanks all.
ETA: That site says the R160 takes 4x AA, but it actually takes 6.
LordLoveLength said:
Useful site.
Looks like an R160 from the earlier photo.
OP double check your speaker wires and battery wires to make sure they are properly connected.
I think you're right. I initially skipped over the R160 because the index page says it uses 4 x AA batteries, but when you go onto the R160 page you can see it uses 6.Looks like an R160 from the earlier photo.
OP double check your speaker wires and battery wires to make sure they are properly connected.
Open this up and click on the R160 for the factory circuit diagram in PDF.
http://www.kbmuseum.org.uk/service_manuals.htm
http://www.kbmuseum.org.uk/service_manuals.htm
NMNeil said:
Open this up and click on the R160 for the factory circuit diagram in PDF.
http://www.kbmuseum.org.uk/service_manuals.htm
Thank you http://www.kbmuseum.org.uk/service_manuals.htm
Now what do I do?
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