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previous: Mike I purchased a 6.3V @ 3A CT transfor... -- 9/15/1999 3:22 AM

Re: DC Filament voltage low

9/15/1999 5:59 PM
Scott	Re: DC Filament voltage low A few things to check: 1. It's a bridge rectifier, right? Make sure the CT of the tranny secondary is taped off and not connected to anything (obvious, I know). 2. Where are you actually measuring? The cap "floats" the circuit and meter may not be measuring the true potential across the filament. I recommend a non-floating filament with the minus of the bridge, the cap negative terminal, and the "-" filament wire all connected to ground and removal of the .047 cap. Now, Hook the meter leads to the output of the 1 ohm resistor and ground and you have no doubt what potential is actually available for the filaments. I have found that a grounded DC filament is usually quieter anyway. 3. The bridge or the 15,000 cap could be bad. Sub other parts.

9/15/1999 5:59 PM

Scott

Re: DC Filament voltage low

A few things to check:

1. It's a bridge rectifier, right? Make sure the CT of the tranny secondary is taped off and not connected to anything (obvious, I know).

2. Where are you actually measuring? The cap "floats" the circuit and meter may not be measuring the true potential across the filament. I recommend a non-floating filament with the minus of the bridge, the cap negative terminal, and the "-" filament wire all connected to ground and removal of the .047 cap. Now, Hook the meter leads to the output of the 1 ohm resistor and ground and you have no doubt what potential is actually available for the filaments. I have found that a grounded DC filament is usually quieter anyway.

3. The bridge or the 15,000 cap could be bad. Sub other parts.

Replies:

Mike I've been measuring across the +/- ... -- 9/15/1999 7:39 PM