Weber Bias-Rite "expectations"?

[FiddlinJim]

Gang,
I bought a single octal bias-rite head with the plate voltage / cathode current switch a while ago. I'm plugging it in to a pretty cheap DMM and getting strange results. The cathode current looks "right" (or is that "rite"?) but the plate voltage looks divided by 10. So, if I'm expecting like 375 Volts, it's showing 37 or 38. Is this a defective Bias Rite or a DMM incompatibility? I've written a couple of email questions to Ted, but haven't gotten a response. I know he's busy and has some pretty enormous health problems, so I haven't wanted to bug him. Any experiences or insight anybody?

[jhadhar65]

According to his website, it should be a 10,000:1 ratio, so Va=375V should read 0.037.  The plate resistor that develops the drop for the plate voltage reading should be 1M.  What is yours?

He's got some pretty hefty spam filters at work over there, so you might try posting to his attention at his kit forum:

http://www.weberorders.com/forum/index.php

[FiddlinJim]

Thanks. I thought the drop was only for cathode current:

"If you purchased the Bias Rite head only, set your voltmeter to read the lowest volts range. Then, the meter will read directly in milliamps. For instance, when your meter reads 35 millivolts (.035 volts), it is indicating 35 milliamps of cathode current."

I assumed that the plate voltage would be straight through. I'll see if I can measure the resistance of the probe's pins tonight.

[jhadhar65]

No, he's got it engineered so you don't have to switch meter scales to get plate voltage - just the Bias-Rite switch.  That might be your issue right there.