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Re: help with ella hum

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tokyofist

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In Reply to: help with ella hum posted by tokyofist on March 15, 2006 at 18:42:23:

well, i'm really running out of ideas here, guys.
new RCA jacks did not fix the problem.
I noticed that barrels on two of the bias jacks were shorting out to the chassis, so I isolated them. still the same noise. right channel is deifinitely worse.
I notice now that both positive speaker posts show continuity with ground. the 24ohm resistors across the + and - post reads fine. could both posts be shorting to ground through the OPTs? could this cause the problem that I describe? any help is appreciated.
dave

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Re: help with ella hum - RHone 21:00:36 03/23/06 (1)
Dave,
The OPT are just one long, long wire between the speaker + and - terminals hence the continuity you observed. I would go back and double, triple and quadruple check all the changes you made. I know sometimes I just have to stare at the circuit for ages until I recognise a problem. Also you might try verifying all the ground connections around the circuit ie. one probe of the multimeter on a known good ground eg PS PCB and then rove around the audio PCB and o/p tubes checking all the ground connections. If you've real buzz-saw hum your probably looking for a disconnection, not just fractions of ohms.
Good luck!
Rod
- Re: help with ella hum - tokyofist 04:40:52 03/24/06 (0)
  thanks rod. sometimes all you need is a little encouragement.

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