Icetube: 14V and no beep after test 3

[stele]

Everything went great up until test 3, where I was getting a good 60V off D3.

After installing C5, R3, Q3, and the last two sockets I did another test with these symptoms:

1. no beep anymore
2. 14V off D3, *and* off the bottom pin of IC3. The troubleshooting guide says this should be 9V. I'm still getting 5V off the top pin of IC3. This is with AND without the tube driver chip installed.

Could shorting something in the MAX6921 area cause the microcontroller to no longer "post"?

My joins aren't the best but everything was working fine up there until near the end. Would love some constructive feedback!

[adafruit_support_bill]

14V off D3, *and* off the bottom pin of IC3.

What are you using to power this? Can you measure the output of your power supply only (disconnected from the clock).

[stele]

Well this is weird. I'm using the 9V power supply that came with the kit. But I just checked it and it's putting out 15V! I believe I remember checking it when I first pulled it out of its packaging, and saw 9V. Could a short in the high voltage section of the board caused the power supply to freak out like this? Or could it have just "gone bad" on its own?

I tried the board with a 12V and 5V power supply I had lying around and still no beep.

[adafruit_support_bill]

Strange. I've never seen one of those power supplies fail like that. Usually the output voltage drops.

Can you post a detail shot showing Q3? The photo is a little dark, but it looks like it might be in backwards.

[stele]

Q3 is a little flatter than a normal round-backed transistor - I had to look at it twice to get the "flat" side right, but it's in properly. (see photo).

Also, the 4th test I did BEFORE installing this transistor (I did the test before I realized I'd skipped Q3). Hopefully leaving it out for test 4 didn't cause a surge.

[adafruit_support_bill]

OK. Let's try replacing the power supply and the processor. Contact support@adafruit.com with a link to this thread and ask for a replacement Ice Tube power supply and processor.

[stele]

I'm willing to do that, but I want to make sure it wasn't something I screwed up first. Is it possible something I did wrong (providing power in the wrong order, or without Q3 installed, or the tube plugged in without the driver chip installed) that could have screwed up the power supply? FWIW, I did leave the power supply plugged in while I was constructing the circuit.

[adafruit_support_bill]

I don't think so. Not even sure that a dead-short would cause the supply to do that. My suspicion is that something in the power supply blew - sending a surge through the system that killed the processor. We sell those supplies by the thousands. We get maybe one or two failures a year, but I have never seen one do that.

[stele]

Okay, I'll do what you suggest. I didn't know power supplies could do that either. Would you like me to send it to you?

[stele]

Question - IC3 is still putting out 5V with the busted power supply. Could the power supply have put a large surge through there when it "went"? I'm curious as to what the failure conditions are on these voltage regulators.

[adafruit_support_bill]

When you contact support for a replacement, you can ask if they want it back, but I don't think it is necessary.

[stele]

Talked to support and they are shipping replacement parts. Will let you know how it goes. Thanks again for your help!

BTW - is there a relatively simple way to tell, with a multimeter and some axillary parts, if an ATMEGA is dead or not?

[adafruit_support_bill]

The fact that your voltage regulator is putting out 5v and the processor doesn't beep anymore at startup is a pretty good indication.

[stele]

Great news!! Got the new power supply and chip today and it's working perfectly! Plugged in the tube for the first time and got 12:00:00 as expected.

Thanks for such wonderful support!