ice cube clock stops working when menu button pressed

[adafruit2]

hiya sorry about this - i thought we fixed this - all kits will have an additional ZVP2110 going forward

any customers who need an extra transistor please email support@adafruit and ask "for phil"

[jarchie]

And I do become upset when I see kit builders blamed for a problem that is probably not their fault, as has happened many times in previous threads.

We do not blame anyone. We offer free replacement parts to solve the problem.

You do indeed, and this is definitely to Adafruit's credit! But it's also why I held my tongue for so long.

Adafruit is an amazing company, and I'm a big fan overall. I'm also a big fan of you, adafruit_support_bill. I do not know you personally, but I've read enough of your posts to respect you. Tirelessly helping end users is not an easy job. My gripe here is with a single part.

Okay, so blame was not the right word. I apologize. But when anyone writes that Q3 was probably static damaged, to me, that implies that Q3 was damaged during assembly. As an end user myself, I trust that Adafruit takes appropriate precautions to avoid static damage, and I would feel responsible for any damage if I accepted "static damage" as an explanation.

hiya sorry about this - i thought we fixed this - all kits will have an additional ZVP2110 going forward

Well color me impressed. I honestly thought I might get banned for my little diatribe.

+10 for Adafruit!

[phild13]

Thank you for the update to Q3.

crispytwo,
This post Ice Tube Q3 Test: MOSFET or PNP Transistor by Russel 27 goes into great detail as to which transistor or FET works best as a replacement for the original kit supplied ZVP3306A FET. The post is a very good read as it provides current and voltage data for the various tested devices in an easy to read chart. Short story is use a ZVP2110A or a PN2907A along with a 470 ohm or 1K base resistor or whatever value between 470 and 1K you may have around. As the chart shows the ZVP3306A passes the least amount of current and voltage, because it does not fully turn on.
Edit: The clock will work excellent with either the ZVP2110A or the PN2907A /with base resistor. I have used both in the clocks with very good results.

[jarchie]

The clock will work excellent with either the ZVP3306A...

The ZVP3306A works well with the majority of clocks and tubes. My objection here is that there is a significant minority of clocks where the ZVP3306A does not work well. The ZVP3306A most commonly causes the dim digit issue, but also occasionally causes the flaky segment problem described in this thread.

[phild13]

Actually it was my mistake and I will edit the posting. I wanted to and should have said:
"The clock will work excellent with either the ZVP2110A or the PN2907A /with base resistor. I have used both in the clocks with very good results."

I would agree that in many clocks, the ZVP3306A would be ok , but there is a segment of clocks that do not work well with the part. Therefore I would think a better performing component would reduce the number clocks that have issues directly related to the ZVP3306A .

[crispytwo]

report:
I received the 2 mosfets (zvp2110a and zvp3306a-nd) and was able to test both in my clock.

I tested the 3306 first.
The numbers were evenly displayed and clear - similar to the jumpered version.
The brightness controls operated normally and as expected.
I then tested the 2110.
The numbers were evenly displayed and clear - the brightness controls operated normally as did the new 3306.

Both are functioning really similarly, so clearly I destroyed the original mosfet.

Thanks for the help in resolving this issue! Really appreciated!

I hope my subjective 'data' is helpful to someone.

[crispytwo]

With my desoldering incompetence, I managed to screw up my board, and now it is a bit worse off.

I thought everything was going ok, but when I was finished putting the enclosure around and plugged it in, the tube started flickering with the movement of the power connector. It seemed to be a connection problem with the board around Q3, and after trying to ensure a good soldering connection, it appears that I managed to remove a pad. :-( -- which was probably caused issue with the flickering.

I will see if I can figure out a work around to it, but out of curiosity, do you sell just the main board and parts?

[adafruit_support_bill]

We do not sell the main board separately. For some tips on repairing lifted pads, see this guide: http://learn.adafruit.com/adafruit-guid ... n-problems
If you post a photo of the problem area, we can take a look too.

[jarchie]

[W]hen I was finished putting the enclosure around and plugged it in, the tube started flickering with the movement of the power connector.

Was this the same type of flickering that you described at the beginning of this thread? Or was it different? Which transistor was installed when you noticed the flickering?

For some tips on repairing lifted pads...

Repairing the board is best solution, but if you cannot make that work there is one other possibility. But I have never tried it myself.

You can try removing Q3 and running a permanent jumper from the voltage regulator output to the input of R3:

Jumper sites for a clock with no Q3

jumper-sites.png (99.49 KiB) Viewed 1241 times

The reason this will work is that the voltage regulator only provides +5v when the AC adapter is attached. D2 will prevent the battery from powering the VFD chip and filament during sleep, so sleep will also work. The jumper can be kept out-of-sight if you run it underneath the board.

Both are functioning really similarly, so clearly I destroyed the original mosfet.

As a side note, I agree that this is the simplest explanation given only that the replacement ZVP3306A worked fine. This was also the case with nearly all previous users who tried that solution.

I've personally witnessed the flaky segment problem disappear and return by simply attaching an oscilloscope probe. Quite a while back, another user was able to make the problem disappear and return by using different 9v adapters! There is always a tiny bit of variation from part-to-part and the flaky segment problem is rare. Together, this explains why a replacement ZVP3306A works when the original does not. By installing a different ZVP3306A, the circuit is changed just enough to eliminate the problem.

[crispytwo]

Was this the same type of flickering that you described at the beginning of this thread? Or was it different? Which transistor was installed when you noticed the flickering?

No, new - it was like a loose wire flickering, like a broken light switch, and the entire tube went 8s then blank and returned to time - whenever the board jiggled (pressed against the plastic cover underneath -- in my excitement, I forgot to bolt it on and it was floppy and pressed there). Q3 was the area.

I'm concerned that it surged and blew a different component with the bursts. I was looking at a similar long wire connection for connecting to R3. I will give your suggestion a try. My intuition says it will be something else now. I'm wondering if the VFD chip is damageable in this way.

Is there any info on the voltage drops I should see going to the tube?

[jarchie]

Is there any info on the voltage drops I should see going to the tube?

It depends on the transistor that is installed. Did you stick with the ZVP2110A?

The post by Russell 27 has specific values, but he was using a 5.05 volt supply and the clock uses a 4.8v or so supply. Still, the values he gives should be similar to what would be observed in an actual clock.

[phild13]

If you want fairly accurate readings from Russell 27's post with what your clock runs at, just subtract .25 volts from his readings. I think he mentions a 4.7 volt average and so recommends subtracting .3 volts this in one of his posts in the thread. You don't really need more accurate readings to see the relationship between the transistors in the chart and which ones work better.
Edit: Found reference to it:
viewtopic.php?f=41&t=51283&start=30#p266570
Most transistors readings did not change much but it was reported that the ZVP3306 did change a lot.

The Maxim VFD has a spec of 3 volts minimum for reliable operation, but most of them probably will work ok at slightly less voltage and I think it is a fairly robust chip, so flickering on and off probably did not affect it.

[crispytwo]

Sorry I've been slow to respond. I've not had the time until today.

tl;dr; my display is dark.

I think I've frankensteined it with minimal scarring and made sure the connections are good. I'm using 3 pins of a chip socket so I can add or remove the mosfet and interchange it with a new one without soldering. The 3 connections from the pins to their respective components are good (via a conductivity test).

• R3 to outside pin of Q3
• IC pin 5 to center pin of Q3
• IC pin 20,21 to inside pin of Q3

I removed and tossed the zvp2110a since it was quite manhandled and put in the zvp3306 that was used in the early successful test... no change. I do have 1 more of each for future reference if needed.

@jarchie
I also attempted the long jumper wire in case that would help -- It didn't in my new circumstance. :-( -- However, I did see " .. b. b. " faintly. I've remove the wire and spent time devising the above.

I went through the standard trouble shooting and came to this measurement:

Low Boost Voltage.
With no tube or VFD chip installed, you should measure between 40 and 70v on the striped end of D3. With a VFD chip installed, you should measure approximately 14-16v.

When I tested this and I'm getting 12.6v at D3 -- which seems potentially too low.

@PhilD13
In reference to 'Russell 27' method, it seemed to me that he is testing the voltage drop across the resistor R3 to ground.
So, my in-circuit voltages (with the tube connected):

• connection at Q3-R3 is 1.97V
• connection at R3-tube is 1.19V

His values were 4.26V and 2.96V respectively (although his are measured at 70 brightness -- which I expect that mine is the default 30)

I really have no idea what kind of failure I've caused to produce this effect since the clock was working when jumpered.

Is there anything I could test to show that the VFD chip is damaged?
Or test that the voltage coming into or out of it is incorrect?
Is it possible that the tube failed?

I'm wondering if I should start a new thread since it is no longer the original problem?

[russell 27]

If your display is okay with jumper, the transistor is the problem. You could always increase display brightness, to adjust higher voltage output. Which to clarify, is the output boost of the inductor, this has no effect on transistor voltage, which solely handles the filament.

[crispytwo]

@Russell27
The jumper did work, until I screwed up my board with desoldering the 'final' time and caused a loose pad on Q3 (I had some strong flickering through all the numbers). Now the jumper has no positive effect. This leads me to believe that I screwed up something else.

It is good to know that the transistor voltage is only the filament.

My thinking is it is related to the high voltage parts, since the other parts I can measure seem to be functioning ok.

Today, I am suspecting the tube. I wonder if the tube is conducting appropriately.

Is there any information on which pins should be conductive and which pins are not?
Is there a guide (list) to inform what the voltage should be for each output pin when operating without a tube connected or with a tube connected?