i need help getting this to work (low voltage

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Longrange
Posts: 3
Joined: Thu Dec 29, 2011 5:22 pm

i need help getting this to work (low voltage

Post by Longrange »

Hi i need some help with the Geiger counter i got from your website for Christmas, i have assembled the whole thing and have been trying to get it to work with little luck. first the ground from the battery connector was not connecting to anything so we added a jumper from it to c5 and now every thing is getting ground, also we are looking at the schematic and noticed r5 and r6 don't match with what was written on the pcb but we looked at pictures on the webpage and found out the pcb was right. also the TLC555CP output is only giving us 3v and tp2 is the same thing, we are using a volt meter rated to 600v. do you have any tips on how to fix/troubleshoot this thanks
Longrange
Posts: 3
Joined: Thu Dec 29, 2011 5:22 pm

Re: i need help getting this to work (low voltage

Post by Longrange »

im going to try replacing the TLC555CP ic and see if that works
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mightyohm
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Re: i need help getting this to work (low voltage

Post by mightyohm »

The first step in debugging is to check all of your solder joints. It sounds like you might have a bad solder connection on the negative terminal of the battery pack. Reflow and add more solder to any joints that look cracked and dull or don't have enough solder on the pad - the solder should make a nice hershey-kiss shape on the pads, with the lead sticking up through the top of the solder joint.

Have you double-checked that the transistors and diodes are installed in the correct direction, matching the photo on the webpage for the kit?

Do you have the FJN3303F installed in the spot for Q1? If the transistors are in the wrong spot, the kit won't work!
dd1968
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Joined: Fri Dec 30, 2011 7:04 pm

Re: i need help getting this to work (low voltage

Post by dd1968 »

You might also want to post a picture of your board .... one of us might spot something out of place.

--Dan
Longrange
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Joined: Thu Dec 29, 2011 5:22 pm

Re: i need help getting this to work (low voltage

Post by Longrange »

thanks guys for the help i first put in a new 555 timer and then it didn't work (oh well only 2 bucks) and then i re-flowed every joint and NOW IT WORKS so thanks for the help.
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mightyohm
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Re: i need help getting this to work (low voltage

Post by mightyohm »

Cool! :D
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