[Boatanchors] B&W 5100 xmtr

Sun, 03 Aug 2003 22:30:16 -0400

David Wilke wrote:
> Does anyone know the resting bias (both PA and Modulator)current in mils recommended for the B&W 5100 xmtr?I cannot find this info in the manual.   [email protected]  
> 

Hi David,

I have a newly acquired 5100 here, so this is a timely topic 
for me.

The PA is class C, so resting bias really isn't an issue. 
You want to see 17 mils of grid drive and load the plate to 
a max of 220 mills, per the manual.  I think that's all we 
need to know.

The modulator is another story.  Mine shows 100 mils 
resting, but the tube data sheets I look at indicate it 
should be something like 32 mils. (Class AB2 with 600 volts 
on the plates.) It's a shame B&W doesn't state the tube 
element voltages. Have you located R44, the pot in the grid 
circuit?  I haven't.  I'm inclined to crank the bias up and 
watch for distortion of a test tone into a dummy load, but 
need to find the adjustment.  Set's been working great, and 
haven't had it out of the cabinet.

Al
-- 
Al Klase - N3FRQ
[email protected]
Flemington, NJ 08822
Web Page:  http://www.webex.net/~skywaves/home.htm