| T O P I C R E V I E W |
| atomic.dave |
Posted - 08/28/2011 : 19:08:36
Here's a photo of my latest setup. I installed the 7616 with the fuse clips soldered to the PCB provided by GQ. I drilled out a hole for the mica window and installed a screen to protect it. I had to crank up the high voltage pot all the way in order for this power hungry GM to work, but it works pretty well, mostly sensitive to alpha.
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| 8 L A T E S T R E P L I E S (Newest First) |
| Odiez1 |
Posted - 08/30/2011 : 12:33:45
Well, ZLM shows a voltage doubler for the GMC-060 in the topic about Alpha sensitivity for the 6017 tube. He's the all knowing one... I'm just trying to help. It looks like an extra diode/ capacitor from the transformer to the 'middle' of the diode/ capacitor set for the positive feed to the tube.
It's not total brain surgery leave R3 and R4 alone on the board. Just add a wire across them. Follow the traces on the board from C3 to R4 to R3 to the positive tube connection. Run the wire underneath to make it easier. |
| atomic.dave |
Posted - 08/30/2011 : 07:43:15
Thats like micro surgery on this board. The chips are small. And what is a voltage doubler? do I buy it and replace the pot with a higher range one? or what? sorry, don't know what this is.
quote:
Originally posted by Odiez1
Bypass is like 'go around' so that means in electrical terms to take something out of a circuit.
One of the resistors, r3 or r4, goes to the positive for the tube, the other is connected to the last of the blue capacitors coming from the transformer.
So basically, the easiest way would be to run a wire from the capacitor leg closet to the positive terminal for the tube, over r3 and r4, directly to the positive terminal. The positive terminal I'm talking about is on the opposite side from all the connectors for power and data. They are SMT resistors, and the board has them labeled..
What about a voltage doubler for the 080?
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| Odiez1 |
Posted - 08/30/2011 : 06:37:55
Bypass is like 'go around' so that means in electrical terms to take something out of a circuit.
One of the resistors, r3 or r4, goes to the positive for the tube, the other is connected to the last of the blue capacitors coming from the transformer.
So basically, the easiest way would be to run a wire from the capacitor leg closet to the positive terminal for the tube, over r3 and r4, directly to the positive terminal. The positive terminal I'm talking about is on the opposite side from all the connectors for power and data. They are SMT resistors, and the board has them labeled..
What about a voltage doubler for the 080? |
| atomic.dave |
Posted - 08/30/2011 : 02:05:35
I'm kinda a novice especially to electronics, but what do you mean by bypass R3 and R4?
quote:
Originally posted by Odiez1
That looks pretty good!
I started out that way also, but I really wanted the probe on the opposite end of the box so that the cords and such wouldn't be in the way of the end the tube. For a portable unit, that's great! Once I added in the external probe, mine isn't as portable..
One question for ZLM tho, does the LND 7616 require the mod mentioned for the 6107?
I ask this because you say the pot was all the way up, and when you do the mod, at least bypass R3 and R4 the voltage at the tube will go up. Then you wouldn't have to peg it.
Also, has anyone heard of the Anton CBON 6109? Found on electronic goldmine as a "voltage regulator" but it looks like a GM tube to me.. My other Anton tube is the 6108, a shorter higher range (less sensitive) version of the 6107.
Also, just saw an Anton 222R on ebay..
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| atomic.dave |
Posted - 08/30/2011 : 02:03:48
Yes, the 7616 definitely needs more power. It is not even close to its potential with Alpha. I have a LND-712 on a different system that gets over 100k cpm with an Americium pellet. And the 7616 here gets under 3000 cpm with the Am. How do I go about increasing voltage on the 080? suggestions?
quote:
Originally posted by ZLM
LND 7616 needs about 720 to 750V volte to work correctly. The GMC-080 550V will start the tube. But to get best result, you may need a mod on hi-voltage part.
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| ZLM |
Posted - 08/29/2011 : 20:21:34
LND 7616 needs about 720 to 750V volte to work correctly. The GMC-080 550V will start the tube. But to get best result, you may need a mod on hi-voltage part. |
| Odiez1 |
Posted - 08/29/2011 : 13:37:00
That looks pretty good!
I started out that way also, but I really wanted the probe on the opposite end of the box so that the cords and such wouldn't be in the way of the end the tube. For a portable unit, that's great! Once I added in the external probe, mine isn't as portable..
One question for ZLM tho, does the LND 7616 require the mod mentioned for the 6107?
I ask this because you say the pot was all the way up, and when you do the mod, at least bypass R3 and R4 the voltage at the tube will go up. Then you wouldn't have to peg it.
Also, has anyone heard of the Anton CBON 6109? Found on electronic goldmine as a "voltage regulator" but it looks like a GM tube to me.. My other Anton tube is the 6108, a shorter higher range (less sensitive) version of the 6107.
Also, just saw an Anton 222R on ebay.. |
| ZLM |
Posted - 08/28/2011 : 19:24:12
Good job. |
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