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Ice tube clock
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Please be positive and constructive with your questions and comments.

Ice tube clock

by sonra on Fri Jul 04, 2014 12:23 pm

Hi
I have a problem in my clock after i finish building the kit and enter the VFD IC into the socket the high voltage converter
give an input of about 10 volts even without the display tube connected . i carefully took the IC out of the socket and the output of the converter arise to 40 volts . I double check it and got the some result
Can you help me ?
Regards Doron
sonra
 
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Re: Ice tube clock

by adafruit_support_rick on Fri Jul 04, 2014 2:08 pm

please post clear, detailed pictures of both sides of the controller board.

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Re: Ice tube clock

by sonra on Fri Jul 04, 2014 4:54 pm

Hi
This are the pictures I hope they are good
Doron
IMG_20140704_233615.gif
IMG_20140704_233615.gif (144.54 KiB) Viewed 543 times
IMG_20140704_233642.gif
IMG_20140704_233642.gif (148.27 KiB) Viewed 543 times
sonra
 
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Re: Ice tube clock

by jarchie on Fri Jul 04, 2014 5:10 pm

In the build instructions, the boost test is done before inserting the VFD driver chip. It is normal for the boost voltage to drop dramatically with the driver chip installed--even without the display attached.

Are you certain that there is a problem? Have you tried making and installing the IV-18 and side board assembly?

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Re: Ice tube clock

by sonra on Sun Jul 06, 2014 7:35 am

Hi ,
I still a problem so I have check with scope
1) the boost circuit as input to q2 the i have pulse of about 2 volts as output a have pulse peek 10 v
2) the output of the VLC are pulses of 10 v peek with the tube connected or not
Any idea ??
sonra
 
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Re: Ice tube clock

by Agent_24 on Sun Jul 06, 2014 8:11 am

Are you able to post any better photos? It's hard to see any detail in the ones already up there.

Have you got the boost converter components all soldered well and around the right way?
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Re: Ice tube clock

by sonra on Sun Jul 06, 2014 3:31 pm

20140706_222447.jpg
20140706_222447.jpg (668.15 KiB) Viewed 506 times
Hi
the components are all well soldered
what should be boost output voltage when the the VFD is in the socket ??
I send a new picture
sonra
 
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Re: Ice tube clock

by adafruit_support_rick on Sun Jul 06, 2014 4:17 pm

Our ice-tube expert is out-of-town this week. Maybe jarchie will chime in - he's also an expert on these clocks.

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Re: Ice tube clock

by jarchie on Sun Jul 06, 2014 10:52 pm

sonra wrote:I still [have] a problem...

What is the problem, exactly? Does the display not light? Do the segments flicker?

sonra wrote:what should be boost output voltage when the the VFD is in the socket ??

Because the boost circuit is open loop, there is no voltage regulation for the boost output. The exact boost voltage will vary from clock to clock. At the lowest brightness setting--the default--boost output is usually around 14 volts (just a guess) with the display installed. I believe that the IV-18 tube should still light dimly at 10 volts.

For example, the Adafruit clock sitting in front of me has a boost voltage of 14 volts at the lowest brightness setting, with the VFD driver chip installed, and with no tube assembly. The boost voltage falls to 13 volts when I insert the tube assembly. When I remove both the tube assembly and VFD driver chip, boost voltage rises to 60 volts.

According to the build instructions, "[y]ou should measure around 60VDC. It may be as low as 40V but not lower." So a boost output of 40v without the VFD driver chip or tube assembly is acceptable. I suspect your boost circuit is functioning correctly, so the problem probably lies elsewhere.

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Re: Ice tube clock

by sonra on Mon Jul 07, 2014 4:38 am

Hi
The problem is not stable dome times the display does not light some time some segments are flickering
Doron
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Re: Ice tube clock

by jarchie on Mon Jul 07, 2014 5:37 am

sonra wrote:The problem is not stable dome times the display does not light some time some segments are flickering

Usually that happens when Q3 is bad. To confirm that Q3 is the problem, please try the jumper test.

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Re: Ice tube clock

by sonra on Tue Jul 08, 2014 4:08 pm

Hi
I try the jumber test . The same results > i see with scope pulse of 10v on the tube board and it is flickering
Any idea does the tube can work on 10 v ?
Doron
sonra
 
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Re: Ice tube clock

by jarchie on Tue Jul 08, 2014 5:48 pm

sonra wrote:I try the jumber test . The same results > i see with scope pulse of 10v on the tube board and it is flickering

Interesting. Would you be able to upload a short video of the display flickering?

Failing that, what does the flickering look like? Do the individual digits or segments flicker independently or does the entire display flicker? Do all parts of the display flicker or is the flickering limited to specific segments or digits? Does the flickering seem random or can you identify some sort of pattern?

I'm only aware of one case where flickering was not due to a bad Q3. The cause was a bad PLCC socket. It might be worth examining your socket closely for similar damage.

In theory, flickering could be caused other dodgy connections in the display driver circuit. Would you post higher resolution photos of the bottom/solder side of the main board so that we could more easily spot any potentially problematic solder joints?

sonra wrote:Any idea does the tube can work on 10 v ?

Yes, I believe the tube will function on 10v. If the problem were due to low boost voltage, I would expect different symptoms: A display where the rightmost digit(s) are too dark to read, but no flickering.

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Re: Ice tube clock

by Agent_24 on Tue Jul 08, 2014 9:59 pm

Check or replace D3, I had one of these where D3 was bad and the boost converter would only produce 10v and the tube didn't light at all.
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Re: Ice tube clock

by jarchie on Wed Jul 09, 2014 12:09 am

Agent_24 wrote:Check or replace D3, I had one of these where D3 was bad and the boost converter would only produce 10v and the tube didn't light at all.

Hmmm... Did you measure 10v when testing the boost circuit or after inserting the MAX6921?

The default boost duty cycle in the Adafruit firmware is 30/256. I just hacked the firmware on my clock to use a boost duty cycle of 10/256. At that duty cycle, the boost voltage was 27.9v without the MAX6921 or IV-18 installed. After inserting the MAX6921, the boost voltage fell to 9.76v. After inserting the display, the boost voltage fell to 9.49v. But even at a boost voltage of 9.49v, the display was still readable in low light. So I would think that a boost voltage of 10v with the MAX6921 installed should still be sufficient to drive the display.

It can't hurt to test D3, as recommended by Agent_24. After all, a bad D3 might cause ~10v from the boost converter and a tube that won't light. My point is only that 10v from the boost converter is sufficient to light the tube, so 10v from the boost converter--by itself--should not cause the tube to fail.

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