Gieger Board Troubleshooting

Support forum for the mightyohm.com Geiger Counter.
http://mightyohm.com/geiger
Post Reply
cheeg
Posts: 1
Joined: Tue Mar 23, 2021 5:12 pm

Gieger Board Troubleshooting

Post by cheeg »

Not hearing anything after powering on the board.

I went through the troubleshooting and I do get the speaker and led to respond when grounding TP1, but nothing when shorting J1 and J2.

A pack of new IN4148s and TLC555CPs are on the way, but are there any other suggestions? See below for picture of the board. Note that the J1 and J2 wires are connected to the tube (not shown in the picture). I verified the contacts to the tube and don't think this is the issue since shorting J1 and J2 doesn't produce anything.
IMG_8362 (1).jpg
IMG_8363 (1).jpg

User avatar
mightyohm
Site Admin
Posts: 1026
Joined: Fri Apr 03, 2009 10:29 pm
Location: Seattle, WA
Contact:

Re: Gieger Board Troubleshooting

Post by mightyohm »

It sounds like the HV supply is not working. I'd start by reflowing any solder joints that look suspect. You can a nice smooth solder joint that fully surrounds each lead. It should look like a hershey kiss when you are done (not too little solder, not too much).

Check that all of your transistors are in the right places - if Q1 and Q3 are swapped that will cause problems. If you have a multimeter you can measure the voltage from each pin of the 555 to ground and compare against the voltages here:
viewtopic.php?p=5489#p5489

Post Reply