I've finished the kit but the brightness is very low.
In MENU the brightness is set to max but the numbers are recognized only in a dark room.
Is this normal?
very low brightness (ICE Tube)
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Please be positive and constructive with your questions and comments.
- adafruit_support_bill
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Re: very low brightness (ICE Tube)
It should be readable in normal room light. What voltage do you measure on the output of the boost converter? Also, what voltage do you measure on R3? http://forums.adafruit.com/viewtopic.php?f=41&t=27032
- monochron
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Re: very low brightness (ICE Tube)
At +UB (the striped end of the diode D5) I measure about 31V. It's too low, I gues.
- adafruit_support_bill
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Re: very low brightness (ICE Tube)
Is that with or without the tube & VFD chip installed? You will want 40v-7v with no chip or tube. It typically drops to the 15v range with the load from the chip & tube.I measure about 31V.
- monochron
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Re: very low brightness (ICE Tube)
That's with tube and chip installed.
While building the kit at test-step I measured 59V.
May I use a wall-power supply with 12V instead the 9V power-supply? Will this rise the brightness?
While building the kit at test-step I measured 59V.
May I use a wall-power supply with 12V instead the 9V power-supply? Will this rise the brightness?
- adafruit_support_bill
- Posts: 88093
- Joined: Sat Feb 07, 2009 10:11 am
Re: very low brightness (ICE Tube)
The clock should run at 12v, but It sounds like you have a very good boost voltage already. Check the heater voltage on R3 - on the end closer to Q3.
- monochron
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Re: very low brightness (ICE Tube)
The heater voltage on Q3/R3 is 3,25 V
When I use the 12 power-supply, heater voltage stay at 3,25V. Boot voltage then is exact 60V and the brightness is better than with 9V power-pupply. Is heater voltage 3,25V OK?
When I use the 12 power-supply, heater voltage stay at 3,25V. Boot voltage then is exact 60V and the brightness is better than with 9V power-pupply. Is heater voltage 3,25V OK?
- adafruit_support_bill
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Re: very low brightness (ICE Tube)
3.25v is a little low. It should be more in the 4.7v range. If you post some photos of the front & back of the board, we can take a look.
- monochron
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Re: very low brightness (ICE Tube)
I've send the photos...
- Attachments
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- Board frontside
- IT_front.jpg (287.66 KiB) Viewed 636 times
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- IT_1.jpg (174.84 KiB) Viewed 636 times
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- Board backside
- IT_back.jpg (354.75 KiB) Viewed 636 times
- adafruit_support_bill
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- Joined: Sat Feb 07, 2009 10:11 am
Re: very low brightness (ICE Tube)
That looks good. Let's get some other voltage readings:
- Pin 5 of the processor chip
Pin 13 of the processor chip
The outer-most pin of Q3
- monochron
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- Joined: Tue Mar 18, 2014 3:46 am
Re: very low brightness (ICE Tube)
Pin 5 of the Processor = 0V
Pin 13 of the Prozessor = 1,254V
Emitter of Q3 = 4,66V
All signals against heatsink of 7805
Pin 13 of the Prozessor = 1,254V
Emitter of Q3 = 4,66V
All signals against heatsink of 7805
- adafruit_support_bill
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Re: very low brightness (ICE Tube)
OK. So it looks like the power sense circuit is working right, but Q3 is not turning on completely to send the full voltage to the VFD and the tube. Can you post a close-up photo showing Q3 from the top? Just to make sure it is installed correctly.
Also, just to confirm the diagnosis, try touching a jumper wire (carefully) between the two outer pins of Q3. This will effectively bypass Q3 and should give you a brighter display.
Also, just to confirm the diagnosis, try touching a jumper wire (carefully) between the two outer pins of Q3. This will effectively bypass Q3 and should give you a brighter display.
- monochron
- Posts: 14
- Joined: Tue Mar 18, 2014 3:46 am
Re: very low brightness (ICE Tube)
When I shortcut Q3 the brightness of the display is OK. It's a little difference, but OK.
- Attachments
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- Q3
- Q3_1.jpg (170.53 KiB) Viewed 615 times
- adafruit_support_bill
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Re: very low brightness (ICE Tube)
It sounds like possibly a flaky Q3. If you contact [email protected] with a link to this thread we can send out a replacement.
These MOSFETs are quite static sensitive. Handle with care on an anti-static surface, if possible.
These MOSFETs are quite static sensitive. Handle with care on an anti-static surface, if possible.
- monochron
- Posts: 14
- Joined: Tue Mar 18, 2014 3:46 am
Re: very low brightness (ICE Tube)
Thanks for the excellent support.
But to save shipping costs I will buy this transistor here in Germany. It will not cost so much (i guess :-). Which designation has Q3? Which type should I order?
But to save shipping costs I will buy this transistor here in Germany. It will not cost so much (i guess :-). Which designation has Q3? Which type should I order?
Please be positive and constructive with your questions and comments.