detector reads 0.00 uSv/h


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Profile Krunchin-Keith [USA]
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Message 604 - Posted: 10 Dec 2011 | 0:14:01 UTC

I put the chip in, replaced the lcd.

hooked up the wires. hook up usb cable.

All i get is "0.00" reading.

If i disconnect tube and touch two wire stogether briefly, i get a chirp and then the "please wait..." message.

i've tried unplugging usb cable and reconnection several times.

restart computer.

took it all apart, removedd chip, replaced it. checked carefully to be sure no bent pins. reassembled everything.

all no help.


Somewhere there was a thread on this i thought, but can't find it.

now what ?

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Message 606 - Posted: 10 Dec 2011 | 0:38:09 UTC - in response to Message 604.

Under the display in a black sponge a controller of the voltage converter is placed. It should be put down in the socket on the right side in such a position, that a small dot (circular depression) located on the chassis of controller found on the right side, bottom (with the letters IC3). Then mount the display back.

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Message 607 - Posted: 10 Dec 2011 | 0:47:21 UTC - in response to Message 606.
Last modified: 10 Dec 2011 | 1:00:13 UTC

I did that, the "controller" is what i refered to as "chip". I did that first "put the chip in". later I also took apart again, removed and replaced it to make sure no bent pins. I've cvhecked it a thrid time now.

the "dot" is mounted at the bottom near the "IC3"

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Message 609 - Posted: 10 Dec 2011 | 4:11:45 UTC - in response to Message 607.
Last modified: 10 Dec 2011 | 4:15:13 UTC

Is it possible you have the polarity of the leads backwards? Do you have a volt meter you can use to determine which one is positive? And you could check the voltage across the leads at the same time.
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Message 610 - Posted: 10 Dec 2011 | 10:29:09 UTC

Did you remove the black sponge from the CON2-pins?
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Message 611 - Posted: 10 Dec 2011 | 11:40:43 UTC - in response to Message 604.


If i disconnect tube and touch two wire stogether briefly, i get a chirp and then the "please wait..." message.


This is attiny crash/reset caused by electromagnetic pulse, hard to believe that because of the very low current, but it happens and has been proven by experiments. This doesn't affect normal operation.



now what ?


Remove the 34063 so there will be no high voltage.
Disconnect the tube.
Plug the sensor to the USB, make sure the BOINC app is not running (it may disable the beeper), take the "+" connector and try shorting briefly again, you should hear occasional beeps (not everytime, just randomly). Note: touching the "+" connector is essential during this test.

http://www.youtube.com/watch?v=HYm79jUpcl0


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Message 612 - Posted: 10 Dec 2011 | 11:49:52 UTC

There is no black sponge at the goldpin connector?

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Message 613 - Posted: 10 Dec 2011 | 12:01:47 UTC - in response to Message 612.

There is no black sponge at the goldpin connector?

As you mention it here: What's it good for BTW? As it's labelled CON2, I think it's something to connect some other device with, but what?
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Message 615 - Posted: 10 Dec 2011 | 13:10:28 UTC - in response to Message 613.

CON2 is port for programmer.
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Profile Krunchin-Keith [USA]
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Message 617 - Posted: 10 Dec 2011 | 13:34:13 UTC - in response to Message 611.


If i disconnect tube and touch two wire stogether briefly, i get a chirp and then the "please wait..." message.


This is attiny crash/reset caused by electromagnetic pulse, hard to believe that because of the very low current, but it happens and has been proven by experiments. This doesn't affect normal operation.



now what ?


Remove the 34063 so there will be no high voltage.
Disconnect the tube.
Plug the sensor to the USB, make sure the BOINC app is not running (it may disable the beeper), take the "+" connector and try shorting briefly again, you should hear occasional beeps (not everytime, just randomly). Note: touching the "+" connector is essential during this test.

http://www.youtube.com/watch?v=HYm79jUpcl0



@Szopler
No sponge on 6 pins of CON2

I did watch the assembly video and did exactly every step.

i double-tripple verified contorller was in correct position, no bent pins and that my wires to tube had correct polarity. I especially marked the "+" on the PCB, wire and tube all in "RED" magic marker so to be sure when I have to disconnect I put them back correctly. I used a yellow wire for the "+" and a black wire for the other, so even with that i can't really mix them up.

@TJM
I took apart again, pulled the controller chip (yes the one that was originally in the sponge, i can't read the numbers on it they are too small. , put lcd back. no radioaactive@home running, i aborted last night and set NNW. didn't see the point of running for 0.00. I watched your test video.
Plugging in usb now. Please wait... 0.00, touch wires breifly many times. NO beeps.

No i went to take the two wires off and redo them, to be sure i had good connection, and the tab that gets pushed down against the wire got puleld out, so i could not get the wire back in. I worked at it and got it out of the way and back in somehow so i could get the wire back in.

I've wasted too much time on this now and have to put it aside.

sad :(

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Message 618 - Posted: 10 Dec 2011 | 16:17:00 UTC - in response to Message 617.
Last modified: 10 Dec 2011 | 16:25:43 UTC

From my own experience (very fresh - today's)
Had 0 all the time, no sound, nothing, but if i lift tube above ground (by hand) all seems to be OK. Value ~0.10 and beeps.
Try this - i'm going to make some more tests. :)
Update: seems i have to touch tube with my finger all the time, doesn't matter position of tube.
:O

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Message 619 - Posted: 10 Dec 2011 | 17:28:08 UTC - in response to Message 617.



@TJM
I watched your test video.
Plugging in usb now. Please wait... 0.00, touch wires breifly many times. NO beeps.



Please do the test again, but this time take a wire, find LM358 (the name may be different, look for "358", as far as I remember it's at the center of the board) and short it's first leg to ground a couple of times (the tube "-" connector is at ground level). 358's output is wired directly to PULSE input so the CPU should count.
If you have a multimeter please check if there is +5V at the 358's pin 8.


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Message 620 - Posted: 10 Dec 2011 | 18:39:03 UTC

To the guys (OK, Basia is probably a girl) having trouble, have you tried putting a smoke alarm on top of the tube? That should give you enough gamma radiation to see something if the sensor is working.

Al.

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Message 622 - Posted: 10 Dec 2011 | 19:04:41 UTC - in response to Message 620.

To the guys (OK, Basia is probably a girl) having trouble, have you tried putting a smoke alarm on top of the tube? That should give you enough gamma radiation to see something if the sensor is working.

Al.

Depending on the type of smoke alarm, mine (an optical one) doesn't have any isotopes inside. But an old TV-set (non-flat) will do, if you go near the screen. Mine produced up to 0,4µS/h in 1" distance.
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Message 623 - Posted: 11 Dec 2011 | 1:50:32 UTC - in response to Message 619.



@TJM
I watched your test video.
Plugging in usb now. Please wait... 0.00, touch wires breifly many times. NO beeps.



Please do the test again, but this time take a wire, find LM358 (the name may be different, look for "358", as far as I remember it's at the center of the board) and short it's first leg to ground a couple of times (the tube "-" connector is at ground level). 358's output is wired directly to PULSE input so the CPU should count.
If you have a multimeter please check if there is +5V at the 358's pin 8.



No multimeter. I can use one at work, but that will ahve to wait until next week.

I assume this is what you meant. i took out the hv controller chip. put lcd back in. no tube connected. i used the black tube ground wire and shorted pin 1 on the lm358 on the backside of the pcb. i got chirps. i got readings on the lcd of 0.95, 0.93 and 0.15 after each set of shorts at differnent speeds and counts. then after a while it drops back to 0.00.


i'll try at work next week to see if there is +5v. i don't have anything i can use here at home at the moment.

No smoke detector within usb randge, i can't pull the detector off the wall and the usb cable is not long enough to reach it, i can't move the computer stack.

NO CRT's here, this is LED LCD land. CRT's went out of style 5 years ago at least. Altough there still is a crt monitor packed in the back of the closet and one or two at work i might be able to try.

i can do more test enxt week, as now i'm in the middle of some liquid kooling builds taht have been dragging on for weeks so i'm trying to get at least one of these two done thsi weekend along with everything else i need to do and Christmas stuff.

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Message 625 - Posted: 11 Dec 2011 | 9:08:41 UTC - in response to Message 623.

Radiation source won't help, something is wrong around the LM358 and the signal just doesn't pass through it. Perhaps one of the nearby elements or more likely one of the connections got damaged during shipment, as far as I know all sensors were tested before shipping.
It's very easy to repair, just find someone with basic knowledge about analog circuits, the schematic is available so it shouldn't take more than a couple of minutes to find what's wrong.



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Message 628 - Posted: 11 Dec 2011 | 21:09:32 UTC - in response to Message 623.
Last modified: 11 Dec 2011 | 22:06:03 UTC

Flip the PCB over and inspect the copper traces for breaks (discontinuities) with a magnifying glass. Look for cold solder joints too. The soldering on my detector was impeccable but nobody's perfect. If you can find a couple replacements for the two LM358N you can switch them out and see if that gets it working.
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Message 634 - Posted: 13 Dec 2011 | 3:21:22 UTC

I have unfortunately got the same thing. I got it working very briefly, returned a couple of units then it seems to have stopped once more and I get 0.00.

The alligator clips I have do not fit on very well though. So I'll replace those. And I used 16gauge wire which was actually a little too big. Do you have any recommend parts for the wire/clips at all ?

My tube seems as if it got just a little crushed on one side too. I'm not certain whether this causes any problems - it is not pierced at all.

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Message 635 - Posted: 13 Dec 2011 | 11:02:19 UTC - in response to Message 634.

Can you show a photo of the tube ?
Your detector worked fine for a while (you got some credits) so I'd say check the connectors first and then eventually follow the test procedures described above.

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Message 636 - Posted: 13 Dec 2011 | 18:40:19 UTC - in response to Message 634.

@Bok

Looks like your sensor started working again a little while ago. The readings looks sensible, but quite 'spiky'.

My bet is a poor connection with the croc/alligator clips. I tried about half a dozen different types (I have a big box of them) until I found a size that gave me confidence in a good connection.

The ones I finally used came from a set of prewired patch leads. For normal use I'd say they were soo small, but in this case they grip really well, and I suspect the teeth cut through any tarnishing on the tube terminals.

Al.

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Message 637 - Posted: 13 Dec 2011 | 21:07:54 UTC
Last modified: 13 Dec 2011 | 21:16:54 UTC

I've used 6mm fuse clips as an "intermediate" between the tube and the alligators. Perhaps you can see it in the last picture in this thread.

Perhaps one day I will ask someone with an soldering equipment to simply solder some wire to such a clip, but for now it's fine, and nothing lasts as long as a good temporary solution ;)

or
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Message 640 - Posted: 14 Dec 2011 | 2:42:33 UTC - in response to Message 636.

I redid the connections a little, but they are still not very good. I need to rethink it and/or take the advice given here. Electronics and such is note really my forte :)

@Bok

Looks like your sensor started working again a little while ago. The readings looks sensible, but quite 'spiky'.

My bet is a poor connection with the croc/alligator clips. I tried about half a dozen different types (I have a big box of them) until I found a size that gave me confidence in a good connection.

The ones I finally used came from a set of prewired patch leads. For normal use I'd say they were soo small, but in this case they grip really well, and I suspect the teeth cut through any tarnishing on the tube terminals.

Al.

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Message 641 - Posted: 14 Dec 2011 | 7:15:40 UTC - in response to Message 640.

Try the easy solutions first. Clean the tarnish off the brass contacts on the ends of the tube. Fine (400 grit) emery cloth or sandpaper or steel wool will do the job quickly. If you don't have those materials then dip a rag in vinegar then dab it in some table salt to pick up some salt grains then rub the brass with the vinegar and salt. Texas Pete's hot sauce works well too. The high voltage at the ends of the leads should punch through a little tarnish but if your clips/connections are not tight and the tarnish is excessive ya never know. A quick cleanup of the tarnish is easy and it eliminates a possible cause.

I redid the connections a little, but they are still not very good. I need to rethink it and/or take the advice given here. Electronics and such is note really my forte :)

@Bok

Looks like your sensor started working again a little while ago. The readings looks sensible, but quite 'spiky'.

My bet is a poor connection with the croc/alligator clips. I tried about half a dozen different types (I have a big box of them) until I found a size that gave me confidence in a good connection.

The ones I finally used came from a set of prewired patch leads. For normal use I'd say they were soo small, but in this case they grip really well, and I suspect the teeth cut through any tarnishing on the tube terminals.

Al.



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