GQ Electronics Technical Support Forum
GQ Electronics Technical Support Forum
Home | Profile | Register | Active Topics | Members | Search | FAQ
Username:
Password:
Save Password
Forgot your Password?

 All Forums
 GQ Electronics Forums
 GQ Geiger Muller Counter
 'Nother newbie
 New Topic  Reply to Topic
 Printer Friendly
Author Previous Topic Topic Next Topic  

liberatorJ

USA
4 Posts

Posted - 11/28/2016 :  09:48:46  Show Profile  Reply with Quote
I'm trying to learn about my GMC-300E Plus that I was given this weekend. I'm a rock & mineral collector and have an autonite specimen ( uranium family) that I wanted to check out. Well, today I was getting readings inside the house and decided to "read" the back yard. I turned it on and left it on the porch for 20-30 minutes. When I next looked at it, I had no readings at all, and since then it doesn't even register in the house where I previously got readings from the granite counter.

Someone have an idea about what's happening? Thanks in advance.

htw
Reply #1

Distelzombie

Germany
141 Posts

Posted - 11/30/2016 :  08:13:07  Show Profile  Reply with Quote
Could you charge the device to the max?
I have the hypothesis that the pot on the circuit board is turned in a way that the tube barely works if the battery is fully charged. The pot sets the voltage for the tube. (Be careful, the voltage is quite high: 300 - 500V.)
If it starts clicking again after you charged it, but then stops a while later, you could try turning the pot very slow in one direction... This either increases or decreases the tubes voltage. I guess you could figure out which way to turn it by turning it. You could damage the tube if you turn the voltage too high.
This is way easier if you have a multimeter.

GMC-300E+ V4.20 with sbt-11 alpha tube
Go to Top of Page
Reply #2

liberatorJ

USA
4 Posts

Posted - 11/30/2016 :  10:30:04  Show Profile  Reply with Quote
Thanks for your input.
I do have a multimeter. I don't know what a "pot" is. Last night I removed the battery cover to check that out and I noticed a small piece of magnetic metal clinging to the battery. It is about 5 mm in diameter and looks like a small button battery, only it is just a small magnet. What it is and function, I have no clue.

htw
Go to Top of Page
Reply #3

ZLM

1024 Posts

Posted - 11/30/2016 :  23:43:51  Show Profile  Reply with Quote
The battery is flat head on positive end. That small magnetic disc is to help the contacting.
Go to Top of Page
Reply #4

Distelzombie

Germany
141 Posts

Posted - 12/01/2016 :  03:40:44  Show Profile  Reply with Quote
With "pot" I mean potentiometer.
https://en.m.wikipedia.org/wiki/Potentiometer

ZLM, do you think this is possible? I mean, in theory the tube voltage is depending on battery voltage, and if the circuit barely provides enough voltage when fully charged...

GMC-300E+ V4.20 with sbt-11 alpha tube

Edited by - Distelzombie on 12/01/2016 03:42:26
Go to Top of Page
Reply #5

liberatorJ

USA
4 Posts

Posted - 12/01/2016 :  10:35:09  Show Profile  Reply with Quote
When I turn on my GMC 300E+, the display says that the battery is 100% so, at this point, I think I will call the company and arrange to send it back for repairs.

Thanks for your help Guys.

htw
Go to Top of Page
Reply #6

Distelzombie

Germany
141 Posts

Posted - 12/02/2016 :  02:02:29  Show Profile  Reply with Quote
That's the solution for everyone and everything I sadly see.

GMC-300E+ V4.20 with sbt-11 alpha tube
Go to Top of Page
Reply #7

ZLM

1024 Posts

Posted - 12/04/2016 :  19:55:36  Show Profile  Reply with Quote
The tube voltage is not depending on the battery voltage.

The tube voltage has it won regulated step up circuit. The circuit works between 3.6-4.2V and the output stays on ~380V always.

So, a full charged battery 4.2V and a low voltage battery 3.6V will provide a same level tube voltage.
Go to Top of Page
Reply #8

Distelzombie

Germany
141 Posts

Posted - 12/08/2016 :  16:48:43  Show Profile  Reply with Quote
So it uses a voltage reference?
Good to know. :)

GMC-300E+ V4.20 with sbt-11 alpha tube
Go to Top of Page
Reply #9

ZLM

1024 Posts

Posted - 12/08/2016 :  20:42:46  Show Profile  Reply with Quote
yes.
Go to Top of Page
  Previous Topic Topic Next Topic  
 New Topic  Reply to Topic
 Printer Friendly
Jump To:
GQ Electronics Technical Support Forum © Copyright since 2011 Go To Top Of Page
Generated in 0.06 sec. Snitz Forums 2000