Help identifying a component please.

Need help with a project? Trying to find a component? Post any general technical questions here.
Post Reply
tascam424
Posts: 3
Joined: Thu Dec 15, 2016 5:38 pm

Help identifying a component please.

Post by tascam424 » Thu Dec 15, 2016 6:12 pm

Hi folks, thank you very much for having me here. I'm a bit of an electronics hobbyist .. I enjoy fixing things, but my overall knowledge is fairly small. So i'm trying to replace a volume control/power switch on an old record player, i've tested the pots and they are dead and to be honest the switch is pretty gritty too ..

My problem is there are no identifying codes of any use, with exception to A503 on the potentiometer.

I have been able to find similar dual potentiometers with the code A503 but without the switch.

So my questions are .. Are all A503 Dual Pots exactly the same ratings ?
And secondly .. Is the switch a separate component or does it come attached ?

I'll attach some photos and hopefully somebody can advise.

Thanks again

Image

Image

Image

Image

Image

David
Posts: 217
Joined: Sun Oct 04, 2015 6:18 pm

Re: Help identifying a component please.

Post by David » Fri Dec 16, 2016 10:29 pm

A503 is the crucial marking. "503" is similar to the colour code - the first two numbers are the value, and the third the multiplier (the number of zeros) so you have a 50,000 ohm pot. the initial letter tells you if it is a log or linear pot, but I have forgotten which is which. If the pots are not completely ruined, try setting the pot to mid-position, and measuring the resistance from the middle tag to each of the others. If the resistance is roughly equal (and try this on each pot) then you have a linear pot, and if one measurement is well different from the other, then you have a log pot.

Similar sized pots will have similar wattage ratings. The switch is the black bit on the end opposite to the shaft, with (pic is indistinct) four tags. It should click as the shaft is turned fully anticlockwise.

tascam424
Posts: 3
Joined: Thu Dec 15, 2016 5:38 pm

Re: Help identifying a component please.

Post by tascam424 » Sun Dec 18, 2016 1:22 pm

Hi there and thank you very much for your response. Yes unfortunately the pots are totally ruined, as in nothing happening at all on them. But you have given me valuable information. I have found the pot on a couple of places online, but i can't find one with the switch. Is the switch a secondary component or is it manufactured with the pot ? They don't appear to want to separate so i'm assuming it is all one component.

Thanks again !

David
Posts: 217
Joined: Sun Oct 04, 2015 6:18 pm

Re: Help identifying a component please.

Post by David » Mon Dec 19, 2016 10:13 am

Yes from your pics the pot is one with an integral switch. I'm slightly surprised that you can't find a dual gang 50K pot with a switch - have you tried Maplins or RS? Btw, a dual gang 47k pot would work just as well, and may be easier to find. Otherwise, you will have to wire in a separate switch. Take the greatest care when working with mains voltages.

What actually happened to destroy the original pot? Check that there is not a fault elsewhere which could trash a new one.

tascam424
Posts: 3
Joined: Thu Dec 15, 2016 5:38 pm

Re: Help identifying a component please.

Post by tascam424 » Mon Dec 19, 2016 9:00 pm

Hi thanks again for your response. Yes i have found numerous 47 & 50k dual gang potentiometers but unfortunately i can't seem to find one with a switch. I tried Maplin and they don't have it at all .. I've also checked RS online, but might be worth a phonemail. It has come of a very old record player and it has been failing over a long time just though wear so i don't believe there to be an underlying cause.

Thanks again .. I'll keep hunting !

magpie
Posts: 32
Joined: Sun Sep 06, 2015 11:34 am

Re: Help identifying a component please.

Post by magpie » Tue Dec 20, 2016 6:54 pm

Try Mouser Electronics UK. They have a range of potentiometers with a switch.

Post Reply