Page 1 of 1

Adjusting HV on Ludlum 12

Posted: Wed Mar 22, 2017 2:18 am
by John Beutz
I bought a ratemeter without looking closely at whether its HV was adjustable. It is stuck at around 860V. Is there any real way to change the output to 1600V (for my BF3 tube), or, alternatively, use some another power supply for the tube and still use the ratemeter to get a signal from neutrons?

Maybe I will just look for a new neutron tube that operates around 900V or below.
IMG_1044.jpg

Re: Adjusting HV on Ludlum 12

Posted: Wed Mar 22, 2017 2:29 am
by Andrew Seltzman
Yes it is, the HV adjustment pot is under the "cal" cover, as is the discriminator control. By the way, if you hold down the HV button, the output voltage will display on the bottom scale on the meter.

Re: Adjusting HV on Ludlum 12

Posted: Wed Mar 22, 2017 2:38 am
by John Beutz
Whelp. It was right there.
Thank you! I need to get my simple investigative skills checked. What would I do without the internet, I wonder.

Re: Adjusting HV on Ludlum 12

Posted: Wed Mar 22, 2017 5:41 pm
by Rex Allers
I know the question has already been answered but I thought I would mention a couple things.

"How do I use this thing I just bought," seems like more of a New User Chat question than something worth preserving in one of the technical sections.

A web search for 'Ludlum Model 12 manual' provided several downloadable pdf's of the user manual. That seems like an obvious place to start looking for an answer.

Strangely, the M12.pdf from the Ludlum site seems to be missing the page with the main diagram of everything on the front panel. There was at least one other older pdf in the search hits that did have this diagram. I just sent an email to Ludlum pointing out the missing page in the pdf they offer.

Re: Adjusting HV on Ludlum 12

Posted: Wed Mar 22, 2017 6:35 pm
by John Beutz
Yes, I asked this question mainly because of the missing page, and my own ignorance of the device and forum procedures. If I can figure out how, I'll delete this post because I also asked it in my other thread (which was also the wrong place for such a question).

Re: Adjusting HV on Ludlum 12

Posted: Wed Mar 22, 2017 7:10 pm
by dario_tortato
Hi, if you have need of the M12 Ludlum manuals, they are present in the forum where I am moderator: http://www.radioactivityforum.it/forum/ ... f=25&t=197
I hope this can be of help.

Dario

Re: Adjusting HV on Ludlum 12

Posted: Thu Mar 23, 2017 2:13 pm
by Richard Hull
Never, ever attempt to erase one of your own posts. It will get a pink slip for sure.

Richard Hull, The "garbage man"