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Ice Clock Tube does not light up
Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.

Re: Ice Clock Tube does not light up - boost voltage low

by BarneyRubble on Wed Jun 04, 2014 10:04 pm

OK I tried changing the Maxim chip and them the Atmel chip - same thing. The segments look like they are counting and are certainly brighter with Q3 bypassed but still lots of missing segments
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Re: Ice Clock Tube does not light up - boost voltage low

by jarchie on Wed Jun 04, 2014 10:49 pm

adafruit_support_bill wrote:I'm curious to see how jarchie's theory pans out.

Sorry to mislead you here. My theory was simply that the problem wasn't with the tube, and I was planning to send a couple replacement parts for BarneyRubble to try. But after realizing that BarneyRubble had parts from another kit, I haven't actually sent anything as of yet. So unfortunately, I don't have any brilliant yet-to-be-revealed theory that I'm holding back on. :-(

BarneyRubble wrote:OK I tried changing the Maxim chip and them the Atmel chip - same thing. The segments look like they are counting and are certainly brighter with Q3 bypassed but still lots of missing segments

The fact that the digits are brighter indicates that Q3 is correctly bypassed. Is there any rhyme-or-reason to the particular segments that are lit or do they seem to be random? For example, is just a particular digit or two that's failing or is it a segment or two that's failing across all the digits?

Right now I can only think of two possibilities... both of which strike me as somewhat remote. First there might be a bad chip socket or bad connections in the board. Second there might be a defective part that's causing other parts to go bad; for example, tube with an internal short might blow certain pins of the VFD chip.

I'll sleep on this information and post back later, but in the meantime, maybe someone else will have a good idea.

Also, BarneyRubble did try cleaning the excess rosin from his board... no luck.

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Re: Ice Clock Tube does not light up - boost voltage low

by BarneyRubble on Wed Jun 04, 2014 11:08 pm

Dudes - here are some photos of the rosin free board and a little video of the tube with Q3 bypassed. I tried 2 tubes - one of them is worse than the other but both brighten up with Q3 bypassed. The video is of the better of the 2 tubes.

Video = http://youtu.be/MDivLgwmt9I
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Re: Ice Clock Tube does not light up - boost voltage low

by BarneyRubble on Wed Jun 04, 2014 11:13 pm

Last pic of the mainboard rosin free.
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Re: Ice Clock Tube does not light up - boost voltage low

by adafruit_support_bill on Thu Jun 05, 2014 5:47 am

One thing is clear, the problem is not due to your soldering. Those are some nice looking boards!

It looks like your top segment is out on all digits. Then there is that odd flicker. Is the same segment missing from the other tube?

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Re: Ice Clock Tube does not light up - boost voltage low

by BarneyRubble on Thu Jun 05, 2014 7:29 am

Yeah - I learned to solder when I was a kid - about 30 years ago..... and it never leaves you if you are taught properly....

The digits - with Q3 by passed on BOTH tubes they look the same. Without Q3 bypassed one of the tubes is barely visible but exhibits the same and the second tube is still relatively bright but same digits missing. As I say I changed the actives out so what next? I do have a second board that I could try and make up to see if there is a problem with anything else but I did want to get one working before I attempted the second one.
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Re: Ice Clock Tube does not light up - boost voltage low

by adafruit_support_bill on Thu Jun 05, 2014 7:38 am

Did you swap the VFD chips too? If you are seeing the same segment missing on two different tubes, I'd normally suspect a soldering problem on the boards. Next most likely suspects would be the VFD chip itself, or a bad contact in the socket.

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Re: Ice Clock Tube does not light up - boost voltage low

by BarneyRubble on Thu Jun 05, 2014 7:43 am

I changed the VFD chip and the microcontroller too - one at a time (old fashioned fault finding too.....) - let me check on the exact digits missing tomorrow. I will bypass Q3 and take a short video of each tube. I will take a close up of the socket - you can see my soldering ain't bad though
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Re: Ice Clock Tube does not light up - boost voltage low

by BarneyRubble on Thu Jun 05, 2014 9:03 pm

HI - Videos. Q3 bypassed.

Tube 1 - http://youtu.be/bU98DnK01eI

Tube 2 - http://youtu.be/UY_gXvOQets

Socket

Looks like one of the springy pins is not good - see annotated photos. This would explain why both tubes show the same digit missing - see videos. Now - once I get that part fixed up - what about tube brightness - is this adjustable?

Apologies on resolution as I used my iPhone on digital zoom - forgot my camera today...

rgds.

Steve
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Re: Ice Clock Tube does not light up - boost voltage low

by jarchie on Thu Jun 05, 2014 10:42 pm

Wow. Good eye!

The odd flickering has disappeared in the last two videos, and the bad pin you found drives segment A--the top segment. The display is multiplexed, so that one bad pin causes segment A to fail across all the digits. Looks like you found the problem!

As for the flickering in the first video, maybe reseating the VFD driver chip fixed that? Normally that kind of flickering is the hallmark of a bad Q3. My theory is that oscillation of Q3 is normally the cause, but in this case, I'm thinking that perhaps another dodgy connection between the driver chip and the socket might have resulted in similar behavior.

With regard to the brightness, yes, it's adjustable through the menus. By default, the clock is on the lowest setting. At the highest setting, the boost voltage is higher and you'll get an unpleasant tingling sensation if you touch the wrong part of the board.

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Re: Ice Clock Tube does not light up

by adafruit_support_bill on Fri Jun 06, 2014 6:06 am

Well done! That should be repairable with a gentle pull if you can find a tool small enough to get in there. Let us know how it goes.

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Re: Ice Clock Tube does not light up

by jarchie on Fri Jun 06, 2014 3:05 pm

adafruit_support_bill wrote:...if you can find a tool small enough to get in there.

If no suitable tool is available, it might be possible to make your own from a sewing pin or needle. First, soften the metal by heating the pin tip until red hot and allowing the pin to cool gradually in the open air. Then, shape the end into a tiny hook or bend with a small pair of needle-nose pliers. Optionally, harden the hook by heating the metal until red hot and plunging the red hot pin tip into a cup of water. Finally, wipe away the excess soot and oxidation with alcohol and a rag.

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Re: Ice Clock Tube does not light up

by BarneyRubble on Mon Jun 09, 2014 3:08 am

Well I pulled the pin and it works better but still not a good contact with a bit of flickering. I really need a new socket. I am worried if I pull it any more it will break the pin.
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Re: Ice Clock Tube does not light up

by adafruit_support_bill on Mon Jun 09, 2014 6:06 am

If you really want a new socket we can send you one. I wasn't going to ask you to undo all that beautiful soldering. That would be quite a chore. Unless you have access to a hot-air-rework station, trying to desolder a PLCC socket is likely to just make things worse.

My recommendation would be a new kit. If you contact support@adafruit.com with a link to this thread we can arrange for a replacement.

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Please be positive and constructive with your questions and comments.