Real-time Environmental Monitoring

This topic has 15 replies, 3 voices, and was last updated 5 years, 8 months ago by uRADMonitor.

Viewing 13 posts - 1 through 13 (of 13 total)

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July 7, 2018 at 9:44 am #5902
ybm
Participant
Hi,

What happend to my A3 unit ?
For a month now I have impossible readings like 8000µSv/h !!!
Have a look https://www.uradmonitor.com/?open=8200009CI
I did restart it this morning but still
Attachments:
1. QQC..png
July 9, 2018 at 12:05 pm #5905

ybm
Participant

Thank you for the tip Wolferl.
I will try that and keep you informed.
And sorry for the wrng link

July 12, 2018 at 6:58 am #5917

ybm
Participant

I open the enclosure take the board out but did not see anything abnormal.
Still giving me weird readings.

July 12, 2018 at 9:51 pm #5936
uRADMonitor
Keymaster
Thanks for your help on this @Wolferl,

It is possible the tube goes into oscillation due to a misbehaving capacitor, called “the compensation capacitor”. Normally all A3 units have it set for 150pF, linked on the type of Geiger tube used (SI29BG), but in this case the value should be bigger to prevent these oscillations that result in high counts.

Either this, or the tube is faulty going in avalanche (unlikely).

You can either send the unit back so I can have a look at it, or change the capacitor yourself based on my indications. I’ll be happy to accommodate any of the two options.
Attachments:
1. compensation_capacitor.jpg
July 13, 2018 at 6:44 am #5939

ybm
Participant

Thank you all,

As my A3 was pen board and one of the wire that rely the sensor to the board was cut.
After re-solder I pass a 300° rework air blow lightly on the card specially in the middle under the Geiger tube.
Since, it seems to rework.

Crossing the finger 🙂

July 13, 2018 at 6:46 am #5940

ybm
Participant

Correction
As my A3 was open board and one of the wire that rely the sensor to the board was cut.

July 13, 2018 at 6:57 am #5941

ybm
Participant

I apply the heat exactly where Radu point on the picture he submit.
By the way, the black wire that was cut maybe also the cause.
I couldnt say if it was cut before or after the opening of the casing.

July 13, 2018 at 10:16 am #5944
ybm
Participant
Everything works fein
The two pic below represent the graphs of the day for my two outside unit rads and temp
Attachments:
1. compare.png
2. compare-temp.png
July 13, 2018 at 10:17 am #5947

ybm
Participant

They are positioned east and west

July 13, 2018 at 3:32 pm #5949

ybm
Participant

Hi

Thanks to you to for helping
Have a great day.

Cheers
Yves

July 15, 2018 at 10:18 am #5955
ybm
Participant
Hello all,

It start again this morning at 8:28 it passes from 0.20µSv/h to more than 9000µSv/h
And the curve is straight til 10:40 then it drop down to “normal” background level around 0.14
It is very ennoying because such readings is not representing the reality at all and should not display on UradMonitor network.
If Radhoo is around , I dont know what to do?
Attachments:
1. voltage-graph.png
2. Rads-15-07-18.png
July 15, 2018 at 11:08 am #5958
ybm
Participant
I have a guess.
It is maybe due to the heat inside the box that disturb something.
At 12:00 today the exhaust indicate 35.6° aand the ambient temp was 30°
At 08:30 the ambient temp was escalating from 30 to 34°that mean at that time the exhaust air from the board might have be 40°
I decide to move the A3 to a new location from screwed to the inside part of the wooden shutter to a cool wall.
Will see
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August 8, 2018 at 9:29 am #5992

uRADMonitor
Keymaster

Hello @ybm,

The unit was fixed, I replaced the compensation capacitors and two transistors in the counting circuit.

The tube itself was OK!

Soon to be shipped back!
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