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logisticalstyles
05-14-2012, 09:38 AM
So last week I decided to finish the LED replacement job I did last year. I had to change my power strobe, 33/45 selector and target lights. I was able to replace them all with no issue except the 33/45 selector on one turntable. I tested it before I reinstalled it, but I noticed something odd. when I put the cicuit board in the turntable chasis only the 45 LED lights up.I double checked my solder connections and everything looks good. When it's not in the chasis everything works fine. I went ahead and re-assembled my turntable figuring I would just have to spin at 45RPM until I figured it out. Well it turns out that the speed selector still works! It's just the LED that does not respond correctly when in the chasis. Has anyone else had this happen to them?

I'm assuming there is a short somewhere but I don't know where to look. I messed around with it for a full day and finally gave up. It looks like I may end up having to replace the whole circuit board eventually. Outside of that one problem, everything came out lovely. Now I just have to repaint them.

DTR
05-14-2012, 11:46 AM
It sounds very much like one or both of the solder points on the PCB for the 33 LED are shorting against the casing. That would explain why it works when you take the PCB out. I suggest taking the PCB out and gluing a little square of paper over the solder connections for the LED. Then test it again. As I recall, there is a little spacing collar that fits between the LED and the PCB. If that's been removed then that's another potential place for a short to occur.

I had a similar problem once, it turned out that the metal case of a transistor was shorting against a metal chassis. I glued a square of paper on the transistor to insulate it and it's been fine ever since (eleven years and counting).

Hope this helps

logisticalstyles
05-14-2012, 04:19 PM
Thanks DTR! I will take a second look at any exposed metal.

DTR
05-14-2012, 04:29 PM
No worries, let us know how you get on

logisticalstyles
08-30-2012, 08:34 AM
3 months later...
I finally got the opportunity to open the decks back up and check for exposed or touching metal.I couldn't find anything and now the light stays on 45 in and out of the case. It's not bothering me too much since I can still switch speeds and it doesn't affect the performance of . I may just leave it until I can order another board. My decks are always a work in progress and one project always leads to another. I'll probably replaced the board when I get around to removing the ground wire.

Thanks for the help.