No longer works after stupid mistake (shorting TP1 and TP2)

[DimV]

Hello,

I assembled my kit, and it seemed to be working but I didn't get as many clicks as I expected, so to test it I shorted TP1 with ground. In the process I learned two things: TP2 is not ground, and I'm an idiot. Now the kit detects nothing at all. It still outputs data to serial just fine, but at a count of 0 per ever. If I briefly short TP1 with an actual ground a count does register, but shorting across the tube clips has no effect.

I replaced the Q2 and Q3 transistors solely on the basis that I had more, but that didn't help. Given all that, does anyone have any ideas on what else I could have broken and how to check it? Any help would be much appreciated!

Sincerely,
Dumb for brains

[mightyohm]

It sure seems like Q2 is fried. Are you sure you replaced it with a working transistor?

Do you hear a faint whine from the speaker when the kit is on?

[DimV]

Thank you for getting back to me! I do hear the whine but just to be safe I replaced Q2 again with another new transistor, however my kit functions exactly as before: no natural counts or from shorting between the clips, but TP1 to ground does register.

I have some replacement parts on order. When they get here I'll try swapping things out until it works, and I'll reply back with my findings. (Or if it doesn't go well, order a whole new kit. :)

It sure seems like Q2 is fried. Are you sure you replaced it with a working transistor?

Do you hear a faint whine from the speaker when the kit is on?

[DimV]

It sure seems like Q2 is fried. Are you sure you replaced it with a working transistor?

Do you hear a faint whine from the speaker when the kit is on?

Further demonstrating my ignorance, I just discovered that the pin I can short to and get a response is not ground, but apparently pin 1 of the pulse connector; that causes a tick, but shorting to ground does not.

So far I've replaced all three transistors (Q1-3), the inductor (L1), one of the capacitors (C2), both diodes (D1-2), the timing chip (U1), and the batteries, with no change. I have a replacement Attiny chip but neither the equipment or the knowledge how to flash it yet (let alone compile code), however unless my new discovery of what ground is (and isn't) indicates another problem that's where I'm heading next.

[mightyohm]

Shorting pin 1 of the PULSE connector to ground is shorting your power supply, so you are effectively resetting the microcontroller. There's a pretty good chance that the ATTINY is fried, given your description.

Send an e-mail to support@mightyohm.com with a short description of your problem and we can work on getting you a new microcontroller to test with!