At 06:04 AM 10/2/2001 -0700, 2 wrote:
> >Tom gets the troubleshooting prize for this problem.
>
>// Agreed
>
> >After pulling the caps,
> >I checked the equalizing/bleeder resistors and found one open! It looks
> >absolutely perfect, no signs of physical damage such as heat, cracks or
> >scrapes. I'll need to get a replacement, then see if the cap is damaged
> >beyond use. It's doubtful at best.
Thinking back a number of years, I had exactly the same experience with the
equalizers in my Viewstar amp. Two of them were open, with absolutely no
visual evidence that anything was wrong. These were 10 watt Ohmite Brown
Devils - decent quality wirewounds by most standards. The resistors
"looked" like new. In my case, the capacitors were fine despite the open
resistors.
Phil
> >
> >Thanks again for all the feedback. It's been an education beyond the
> initial
> >problem.
> >
>// Unreliability is why we do not proffer wire-wound resistors for
>electrolytic capacitor equalizer/bleeder service. Although lower value
>wire-wound resistors are fairly reliable, as you have apparently
>discovered, such is not the case with higher-value units.
>- My guess is that the capacitor that had the open bleeder has white
>deposits around the pressure vent. and/or shows higher leakage @450v.
>Replacing the entire string of capacitors with new, 105ºC units might be
>best. I would also replace the wire-wound equalizer resistors with MOF
>resistors because they are more stable & more reliable. /sources:
>Mouser Electronics -- 800.346.6873. Digikey -- 800.344.4539/
>
>cheers, Mark
>
>- R. L. Measures, 805.386.3734, AG6K, www.vcnet.com/measures.
>end
>
>
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