|
11)
Message boards :
Cafe :
USB or BOINC troubles?
(Message 3448)
Posted 2953 days ago by --Norbert For anyone with a R@H sensor that works (clicks/flashes) but has USB or BOINC troubles, note that the serial output can be used at another radiation site, http://www.radmon.org. Search that site's forum for '@home' for a how-to post by Bert490. |
|
12)
Message boards :
Number crunching :
using a GMC-300 for a project detector?
(Message 3421)
Posted 3017 days ago by --Norbert There are other options for you to contribute with your GMC-320+, if this site proves too difficult. The following alternate sites are compatible with that detector: www.radmon.org www.netc.com www.gmcmap.com |
|
13)
Message boards :
Science :
1/2 x like graph starting on Dec 29. - ideas?
(Message 3414)
Posted 3037 days ago by --Norbert When this happens, does the LCD display also show the same values, alternating high and low? If so, there must be a problem with the tube or electronics. In addition, before the spike, the hourly values seem to be mostly the same value, not fluctuating naturally. All the other sensors show variation every sample and for the hourly values too. If the LCD display does not change on a second-by second basis, this also points to a detector issue. |
|
14)
Message boards :
Science :
Strange graph
(Message 3407)
Posted 3061 days ago by --Norbert Something seems wrong with your graph. Does the detector display show a steady value? |
|
15)
Message boards :
Science :
What value is R8 on a v2.60 kit?
(Message 3401)
Posted 3076 days ago by --Norbert It looks to me that this resistor is used to recharge C9 after each detection click at a predictable fast rate, so that high counts can be seen reliably. Using a value 10x higher would I think have little effect at low count rates (I could be wrong). But I don't see how a higher value would result in overheating; lower yes but not higher. I would check other components too for proper values, especially DZ4, R9 and C9, also R12 and R18, in case they are the cause of the over-current. |
|
16)
Message boards :
Science :
Can not Disable Buzzer and Backlight (Help)
(Message 3394)
Posted 3092 days ago by --Norbert The backlight and buzzer on the detector are not under BOINC software control. This is changed with the pushbuttons on the detector. Press the middle one repeatedly to cycle through backlight and display options. The right button cycles through LED and buzzer options. To avoid waiting for one of us to reply, searcy the forum (up to a year ago search is possible in 'advanced search'). |
|
17)
Message boards :
Science :
Detector Defect
(Message 3374)
Posted 3132 days ago by --Norbert Now that I see the backside of your board, I see DZ4 is in the proper spot for that version, due to the layout problem (thanks, rattorosso). You can check this DZ4 with the board un-powered using the diode test function of your meter. It is shared with the '2k' setting near the 10:00 position on the dial. With the black lead touching the diode's banded end (right side in photo) and the red lead on the bent leg, the meter should read between 600 and 700 or near there (this is millivolts of forward drop voltage). With the leads reversed, the meter should read infinity, which is a '1' on the left side of the display. To measure R12 and R18, also do not power the board. Use the '20M' setting near 12:00 on the dial. For this the leads can be either way across each resistor, and the reading should be within 5% of 5.1. The 2 orange devices are capacitors (C10 and C13) and they are in the correct position near the tube, not near DZ4. They are not likely bad because the tube voltage seems OK. |
|
18)
Message boards :
Science :
Detector Defect
(Message 3371)
Posted 3133 days ago by --Norbert Hang on a sec. Where is DZ4? There's nothing there in the photo. I believe it is necessary to protect IC1 from high voltage spikes when the tube fires. Was it really working before without this? In any case, it's possible that IC1 is now damaged. I would buy a replacement DZ4, IC1 and any resistor that is way over it's proper value. Solder in DZ4 and any bad resistor, then see if it works. If not, clip all the leads of IC1, de-solder the 8 pins still in the holes, and solder in the new IC1. |
|
19)
Message boards :
Science :
Detector Defect
(Message 3370)
Posted 3133 days ago by --Norbert It was working before, so it must be one of: - new tube is installed backwards (Plus on the board, other end hanging out with loose wire attached) - new tube is no good - something else on the board is bad. As Karmanngaz says, look closely at the solder joints; maybe one came loose when the tube got damaged. Pay most attention to the area around IC1, the 8-pin chip. That is where the detector circuit is. I'm not sure how to reliably check the pulses coming out of pin 1 of that IC, they are likely very short so won't show up on a digital meter. This is where the old needle type meters are better (you would see a little jump on the needle every time the tube fires). Hmm, you can also measure the resistances using your multimeter on the ohms scale (the omega part at the dial's top left). Use the setting appropriate for each resistor value and google 'resistor color code' to read the bands. The readings should never be higher than the resistor value (within 5%), but can be lower due to other components in the circuit. |
|
20)
Message boards :
Science :
Detector Defect
(Message 3358)
Posted 3149 days ago by --Norbert I think the circuit is good based on your 204 V reading. The measurement location of the probes means that the overall tube voltage is 408 V, which is what the tube needs. It should work with your new tube. For future reference, all other voltage measurements mentioned should be made with the black probe at 0V or ground, and the red probe at each location. The black chip (IC) pins are numbered counter-clockwise with pin1 marked with a small indentation (lower left here). So on the big chip IC1, pin 5 is correctly shown by your green arrow below. But pin 3 would be to the left of that, and your red arrow points to pin 12. |