Heater voltage measurement

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briango2000
Posts: 7
Joined: Sat Nov 29, 2008 9:01 am
Location: Salem, OR

Heater voltage measurement

Post by briango2000 »

For the 6.3 VAC on the heaters...I should be measuring across both pins that the heaters are wired to?
paulster
Posts: 1299
Joined: Tue Oct 10, 2006 5:08 pm
Location: Los Angeles & London

Re: Heater voltage measurement

Post by paulster »

Correct.

The centre-tap of the transformer heater winding is tied to ground, so if you keep your black multimeter lead clipped to the chassis as you'd normally do then each of the heater pins should read 3.15Vac relative to ground, or 6.3Vac between the two pins.

Just be careful when using two hands inside the amp to measure across two pins. It's best to have the amp in standby mode to do this, with the B+ caps discharged, although there are still healthy voltages floating around at the power supply end of the chassis.

Paul
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