Alba 432 record player - UK Vintage Radio Repair and Restoration Discussion Forum

kirstyd · 23rd Dec 2017, 10:00 pm

managed to save this from being thrown away this morning [worth it just for the cartridge] apart from the motor running there are no signs of life when its switched on .Theres power coming back to it from the motor but thats it totally dead .I have tested the speaker and its fine but thats about as far as i have got .On opening the thing up i found that someone has fitted a socket on the side presumably for a guitar or some other device .It was fitted into the pick lead up in such a way that the cartridge would be disconnected when a plug was inserted i have since removed anything that shouldn't be there and its now back to its original state .the little amplifier [as far as i can see]only has three transistors .I will investigate further but in the mean time if anyone has any suggestions on what may be wrong with it i would be most greatfull

Edward Huggins · 23rd Dec 2017, 10:08 pm

Check that c. 12-18V is coming from the motor tapped winding to power the amplifier.

Cobaltblue · 23rd Dec 2017, 10:19 pm

I don't have much to do with record players however that amplifier looks very similar to the RP6 http://www.service-data.com/product.php/242/569/a10242

As for faults, dry joints, faulty transistors open circuit bridge rectifier, anybody's guess start by taking the static voltages on the transistors.

Cheers

Mike T

kirstyd · 28th Dec 2017, 9:23 pm

Well I have been fiddling with this for a couple of hours now and have checked various voltages against the ones on the diagram. While doing this I found resistors 3 an d4 were reading high, so I replaced them and while doing this I knocked the VR4 pot and the thing burst into life for a few seconds. So I cleaned the pot with a cotton bud and some switch cleaner. That seemed to do the trick. Next I had to remove the volume control dismantle it and clean it [it wouldn't respond to the usual squirt of switch cleaner] and after putting it back in the thing seems to be working with a CD player going through it but there now seems to be another problem that being that while the volume control is working perfectly the tone control is also turning the vol up and down. As you can just see in photo one in the first thread the pick up lead was connected to the centre tag on the tone control and the earth tag. I have since put it back as it should be or at least how it is in the diagram.

Any ideas boys?

Edward Huggins · 29th Dec 2017, 11:15 am

In this circuit it looks as if the tone control follows the volume control before the 1 stage of amplification. I would re-check your wiring for shorts and also that the tone control capacitor (next to the tone control) is not shorting or has become disconnected.

kirstyd · 29th Dec 2017, 1:53 pm

Thanks Edward will do.

kirstyd · 29th Dec 2017, 6:01 pm

You were right Edward. I checked what I had done and couldn't find anything wrong. I then checked the three connections on the vol pot and found one of them to be bad. A quick heat up with the iron put it right and it's working as it should for what it is.

Thanks guys for the usual good advice.

23rd Dec 2017, 10:00 pm	#1
kirstyd Heptode Join Date: Mar 2014 Location: Leeds, West Yorkshire, UK. Posts: 902	Alba 432 record player managed to save this from being thrown away this morning [worth it just for the cartridge] apart from the motor running there are no signs of life when its switched on .Theres power coming back to it from the motor but thats it totally dead .I have tested the speaker and its fine but thats about as far as i have got .On opening the thing up i found that someone has fitted a socket on the side presumably for a guitar or some other device .It was fitted into the pick lead up in such a way that the cartridge would be disconnected when a plug was inserted i have since removed anything that shouldn't be there and its now back to its original state .the little amplifier [as far as i can see]only has three transistors .I will investigate further but in the mean time if anyone has any suggestions on what may be wrong with it i would be most greatfull Attached Thumbnails

23rd Dec 2017, 10:08 pm	#2
Edward Huggins Dekatron Join Date: Sep 2015 Location: Southwold, Suffolk, UK. Posts: 8,325	Re: Alba 432 record player Check that c. 12-18V is coming from the motor tapped winding to power the amplifier. __________________ Edward.

23rd Dec 2017, 10:19 pm	#3
Cobaltblue Moderator Join Date: Dec 2010 Location: Exeter, Devon and Poole, Dorset UK. Posts: 6,857	Re: Alba 432 record player I don't have much to do with record players however that amplifier looks very similar to the RP6 http://www.service-data.com/product.php/242/569/a10242 As for faults, dry joints, faulty transistors open circuit bridge rectifier, anybody's guess start by taking the static voltages on the transistors. Cheers Mike T __________________ Invisible airwaves crackle with life or at least they used to Mike T BVWS member. www.cossor.co.uk

28th Dec 2017, 9:23 pm	#4
kirstyd Heptode Join Date: Mar 2014 Location: Leeds, West Yorkshire, UK. Posts: 902	Re: Alba 432 record player Well I have been fiddling with this for a couple of hours now and have checked various voltages against the ones on the diagram. While doing this I found resistors 3 an d4 were reading high, so I replaced them and while doing this I knocked the VR4 pot and the thing burst into life for a few seconds. So I cleaned the pot with a cotton bud and some switch cleaner. That seemed to do the trick. Next I had to remove the volume control dismantle it and clean it [it wouldn't respond to the usual squirt of switch cleaner] and after putting it back in the thing seems to be working with a CD player going through it but there now seems to be another problem that being that while the volume control is working perfectly the tone control is also turning the vol up and down. As you can just see in photo one in the first thread the pick up lead was connected to the centre tag on the tone control and the earth tag. I have since put it back as it should be or at least how it is in the diagram. Any ideas boys? Attached Thumbnails

29th Dec 2017, 11:15 am	#5
Edward Huggins Dekatron Join Date: Sep 2015 Location: Southwold, Suffolk, UK. Posts: 8,325	Re: Alba 432 record player In this circuit it looks as if the tone control follows the volume control before the 1 stage of amplification. I would re-check your wiring for shorts and also that the tone control capacitor (next to the tone control) is not shorting or has become disconnected. __________________ Edward.

29th Dec 2017, 1:53 pm	#6
kirstyd Heptode Join Date: Mar 2014 Location: Leeds, West Yorkshire, UK. Posts: 902	Re: Alba 432 record player Thanks Edward will do.

29th Dec 2017, 6:01 pm	#7
kirstyd Heptode Join Date: Mar 2014 Location: Leeds, West Yorkshire, UK. Posts: 902	Re: Alba 432 record player You were right Edward. I checked what I had done and couldn't find anything wrong. I then checked the three connections on the vol pot and found one of them to be bad. A quick heat up with the iron put it right and it's working as it should for what it is. Thanks guys for the usual good advice.