OldTuna Posted September 3, 2009 Share Posted September 3, 2009 Got an old Wurly 140B that's developed a nasty ground hum, especially from the 1/4" jack. The speaker's a bit more quiet but the hum is still there. Is this something simple to stop or is it time for more serious repairs? Link to comment Share on other sites More sharing options...
B3bluesman59 Posted September 3, 2009 Share Posted September 3, 2009 You will have to open up the board and start checking for loose wire ground connections. That is usually the problem with getting "hum" on those older Wurlies. I had a couple of them and each time I fixed it by running down loose connections. Make sure too that you have a three prong grounded AC cord. That sometimes too can be the problem. The 140B came from the factory with a standard two prong AC cord...not good. Link to comment Share on other sites More sharing options...
mate stubb Posted September 3, 2009 Share Posted September 3, 2009 The filter caps on the power supply may have given up. Moe --- Link to comment Share on other sites More sharing options...
OldTuna Posted September 4, 2009 Author Share Posted September 4, 2009 Thanks for the help, guys. I had a feeling that it might be the caps....everything else seems to be good. I'll look into that and let you know what I find. Again, thanks for the good info. Link to comment Share on other sites More sharing options...
Throbert Posted September 4, 2009 Share Posted September 4, 2009 If there's a ground pin on the AC try lifting it with an adapter otherwise...yea the AC Hz has ate through the caps. Triton Extreme 76, Kawai ES3, GEM-RPX, HX3/Drawbar control, MSI Z97 MPower/4790K, Lynx Aurora 8/MADI/AES16e, OP-X PRO, Ptec, Komplete. Ashley MX-206. future MOTU M64 RME Digiface Dante for Mon./net Link to comment Share on other sites More sharing options...
B3bluesman59 Posted September 5, 2009 Share Posted September 5, 2009 The reed bar shield is the first place to check for hum. Also check out this site for 140B parts: http://www.vintagevibe.com/c-20-model-140b-parts.aspx Link to comment Share on other sites More sharing options...
BillWelcome Home Studios Posted September 5, 2009 Share Posted September 5, 2009 I have bought a lot of vintage equipment over the years, including quite a few amplifiers from the 40s and 50s. Sometimes, you can solve the problems by reheating the solder joints. Solder scales over time, and simply re-liquefying the solder can remake connections that were turning into capacitors. Go through the circuit, re-making every connection (including the jacks...) I ONLY recommend this if you are knowledgeable about working inside of electrical equipment though. If not, do NOT do this. When doing this, give a visual inspection to the parts. Cooked resistors are pretty obvious, but it is often possible to see other flaky parts, too. And then there are the big caps in the power supply. They dry out over time, and need replaced. No not, EVER lift the ground pin. EVER. "I believe that entertainment can aspire to be art, and can become art, but if you set out to make art you're an idiot." Steve Martin Show business: we're all here because we're not all there. Link to comment Share on other sites More sharing options...
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