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Title: Tech Opinion Please Post by: MrGoldTop on March 27, 2012, 10:18:25 PM I was checking out my C-Lator build the other day starting with basic voltage measurments like filament voltage, etc. Connected alligator clips of my DMM to pins 4-5, 9 and while measuring I think the clip on pin 9 might have slouched over and briefly touched pin 8 (47uf electorlytic cap). Could I have fried the cap with that AC voltage?
Thanks Title: Re: Tech Opinion Please Post by: SoundPerf on March 28, 2012, 02:40:19 AM I wouldn't worry about it too much. Have you noticed any strange measurements or increased noise? Was it on there long?
In the end it was only getting half wave voltage. Title: Re: Tech Opinion Please Post by: MrGoldTop on March 28, 2012, 03:24:23 PM The reason I posted was that I couldn't get a good measurement of the capacitance. But my DMM sometimes gives strange results especially in the higher uf range. I have since powered it up and all voltages agree with those in the voltage chart. I'll be playing through it tonight. I guess that will be the ultimate test.
Thanks again Title: Re: Tech Opinion Please Post by: MrGoldTop on March 29, 2012, 05:06:03 AM I got to check it out tonight and there is quite a bit of noise when using it. Coming out of the recovery stage. Noise varies with pot position and the bright switch actually reduces the noise. So I'll probably change out the cap.
Title: Re: Tech Opinion Please Post by: SoundPerf on March 29, 2012, 05:14:48 AM I got to check it out tonight and there is quite a bit of noise when using it. Coming out of the recovery stage. Noise varies with pot position and the bright switch actually reduces the noise. So I'll probably change out the cap. Yeah, sounds like a good idea. Still sort of suprising, but not impossible. Hope this fixes it. If you get a chance report with progress.... P.S. It might be worth swapping another tube in there if you have one, just to rule out tube damage. Title: Re: Tech Opinion Please Post by: MrGoldTop on April 02, 2012, 02:11:07 AM Update
Swapped out the tube for a Raytheon BP (Probably a waste of a good vintage tube) but it sounds much better. Might just replace the cap anyway. Title: Re: Tech Opinion Please Post by: SoundPerf on April 02, 2012, 02:46:13 AM Update Swapped out the tube for a Raytheon BP (Probably a waste of a good vintage tube) but it sounds much better. Might just replace the cap anyway. You know due to the way you posed the question and me not giving it a proper consideration, I was approaching this from a standpoint of the heater voltage on the cap, but possibly the bigger issue was the fact that the cathode voltage was on the heater filament. I forget what sort of voltage is on pin 8, but I know it doesn't take much to ruin the tube filament. Replacing the tube is probably a good idea. Here's a write-up about testing caps. It's probably easier to just replace the thing, but you may me interested in knowing for sure. Glad you're making headway. http://www.angelfire.com/electronic/funwithtubes/Testing_caps.html (http://www.angelfire.com/electronic/funwithtubes/Testing_caps.html) Title: Re: Tech Opinion Please Post by: MrGoldTop on April 03, 2012, 04:15:20 AM Changed out the cap and it all sounds good. Thanks for the help.
Title: Re: Tech Opinion Please Post by: SoundPerf on April 06, 2012, 01:12:11 AM Changed out the cap and it all sounds good. Thanks for the help. That's good news. Happy Jam'n! |