ICE TUBE:low voltage w boost controller chip

[mattkpetersen]

The tube does light, but very briefly. Maybe a second or more, and then it flickers out.

EDIT, Sorry, scratch that. When I short the second and third pins on Q3, the tube briefly lights. It does not light when I short the first and third pins. Where the first pin is the pin adjacent to the edge of the board.

[adafruit]

hmm i think we should just try a new kit - email support@adafruit with a link to this post and receive a new ice tube clock kit!

[mattkpetersen]

I'll do so. Thanks for your help.

[Th0mw4lker]

Hi there,

working on my own Ice Tube kit here and had a similiar issue - no display on power up after sucessful power supply tests. Shorted pins 1 to 3 on q3 as suggested in this post and the display lit weakly but seemed correct (blinking default time). Also able to cycle menus. Q3 is installed corrrectly per the silk screen - could it be blown?

Thanks!
Thom

[adafruit_support_bill]

Thom -
Let's start by getting the 4-digit number from the small tube-board. Also, photos of the front & back of the board. In particular the area around the battery sense circuit (R1, R2, C10) and the tube heater circuit (Q3, R3)

[Th0mw4lker]

Board Number is 4111

Photos attached

Please note that I completed the project after shorting Q3 (and eventually replacing Q3 with a jumper wire) so I could program and play with the clock (I was bored). The tube displays the correct time, date, and menus - it's just a bit dim. I removed the VFD and checked the voltage on the cathodes of D3 and D5 - right around 56 vdc. The clock "works" just not sure why it's so dim with Q3 removed.

Thanks!
Thom

photo1.JPG (113.99 KiB) Viewed 1309 times

photo2.JPG (173.87 KiB) Viewed 1309 times

photo3.JPG (206.87 KiB) Viewed 1309 times

[adafruit_support_bill]

Q3 is there to turn off the display when the power goes away so it won't drain the backup battery. The symptom you see is often caused by a problem in the battery sense circuit. With the clock on, what do you measure on pin 13 of the microprocessor?

As for the dim display. It does default to a fairly low setting at initial power up. Are you able to alter the brightness from the menu?

[Th0mw4lker]

Yeah - Actually it's quite bright now (didn't try earlier - duh). So Q3 is removed during my tweaking - when I replace it I go back to getting no display. I guess Q3 is shot?

[adafruit_support_bill]

With the clock on, what do you measure on pin 13 of the microprocessor? It could be a problem in the battery sense part of the circuit.

[Th0mw4lker]

Sorry for the delay - work interferes with my life! Clock on, pin 13 is 1.25v

??

Thanks!

[adafruit_support_bill]

That is above the battery sense threshold (~1.1v), so the processor should be sending power to the VFD via Q3. What voltage do you measure at the gate (center pin) of Q3? It should be pulled low to turn on.

[Th0mw4lker]

I'm getting .32v on the center pin of Q3

[adafruit_support_bill]

What happens if you short that to ground?

[Th0mw4lker]

Nothing -

[adafruit_support_bill]

Can you read the part number on Q3?