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liberatorJ
USA
4 Posts |
 Posted - 11/28/2016 : 09:48:46
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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 |
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| Reply #1
Distelzombie
Germany
202 Posts |
Posted - 11/30/2016 : 08:13:07
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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-11a alpha tube
My statements are "stuff-a-hobbyist-says" and not in any way professional. |
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| Reply #2
liberatorJ
USA
4 Posts |
Posted - 11/30/2016 : 10:30:04
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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 |
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| Reply #3
ZLM
1261 Posts |
Posted - 11/30/2016 : 23:43:51
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| The battery is flat head on positive end. That small magnetic disc is to help the contacting. |
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| Reply #4
Distelzombie
Germany
202 Posts |
Posted - 12/01/2016 : 03:40:44
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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-11a alpha tube
My statements are "stuff-a-hobbyist-says" and not in any way professional. |
Edited by - Distelzombie on 12/01/2016 03:42:26 |
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| Reply #5
liberatorJ
USA
4 Posts |
Posted - 12/01/2016 : 10:35:09
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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 |
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| Reply #6
Distelzombie
Germany
202 Posts |
Posted - 12/02/2016 : 02:02:29
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| That's the solution for everyone and everything I sadly see. |
GMC-300E+ V4.20 with sbt-11a alpha tube
My statements are "stuff-a-hobbyist-says" and not in any way professional. |
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| Reply #7
ZLM
1261 Posts |
Posted - 12/04/2016 : 19:55:36
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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. |
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| Reply #8
Distelzombie
Germany
202 Posts |
Posted - 12/08/2016 : 16:48:43
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So it uses a voltage reference?
Good to know. :) |
GMC-300E+ V4.20 with sbt-11a alpha tube
My statements are "stuff-a-hobbyist-says" and not in any way professional. |
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| Reply #9
ZLM
1261 Posts |
Posted - 12/08/2016 : 20:42:46
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| yes. |
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'Nother newbie
