Another newbie question (top digit on tube doesn't light))

[teeroy]

Well my son and I just completed the ice tube clock (his first electronic project) and All went well. We then plugged it in to discover that the top segment of each digit would not light. I've read some of the other posts on missing segments and am stumped. I've re soldiered all the connections that pertain to the driver and the tube. I guess the real problem is that I'm having problems reading the schematic and finding the exact pin/wire location on the ic and the tube for that top part of the digit. can someone help me locate the area that I need to focus on? I've also tested continuity on all the pins. All seems ok. I'm stumped. HELP! THANKS.

[teeroy]

Sorry here is a pic of the problem.

[adafruit]

resolder the tube, the headers and the VFD driver socket

[teeroy]

Thanks for the fast response. Yup I just spent the afternoon re working the areas that you described and checked the continuity (twice). I still have no top segment in all of the digits any other ideas? Here is some pics.

[adafruit]

looks like way too mcuh solder on the tube, the blobs are touching?

[Rotzog]

Yup, looks like you are shorting out pin 12, the segment A anode.

http://www.ladyada.net/make/icetube/download.html

Look for the mini data sheet for the IV-18 tube.

[teeroy]

I'll look again and focus on pin 12. The solder is getting messy because I've went over it three times. if there isn't a bridge where would you look next.

[teeroy]

Ok I went and found pin 12 and traced all the solder joints to the driver and re-soldered them again and tested for continuity and shorts, all ok. Still no top segments lit when I powered it up. can I test to see if the driver is delivering any power to that pin? What voltage should it be and where do I place the negative side of my meter? Is it possible that the driver is bad?

[adafruit]

sadly, you might have 'poofed' the VFD driver if you shorted the pin to another one - which is really looks like from the photo
use
http://www.ladyada.net/media/icetube/IV-18.pdf
and
http://www.ladyada.net/media/icetube/ic ... emv1.1.png
to verify which pin is VFD segment 'A'
then use a multimeter to do a continuity test between that pin and the ones next to it (shouldnt be)
then do a continuity test between that pin and the corresponding VFD driver pin (should be)
if you've found that its NOT shorted to another pin but it IS connected thru to the VFD you can buy a new VFD from us at support@adafruit

[teeroy]

yup it must be the driver. #12 pin and the ones on either side are clear to the VFD driver socket. . when I put the VFD driver back into the socket the pin next to #12 shorts to it and also one on the other side of the circle as noted in the picture. I'll place my order for a new VFD ASAP. I hope it works.

[adafruit]

yup, well at least you have debugged the issue. poor zapped VFD luckily easy to replace with a socket

[teeroy]

Thanks for sending the part out, I just got it last night. This morning I placed it in and fired it up! No good. same problem. I think my next step is to check the top digit(segment) separately to see if it will light, any tips on doing this? my next procedure will be removing the tube driver socket and re-solder that to the board

[adafruit]

yes its 'down the line'
please return the tube (well packaged) if you can - we'll send it to the next person with a problem