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One last check you could make before it starts to get complicated... can you measure the voltage at each end of the LEDs to ground?. It would be a good idea to remove L1 for now as you won't need the high voltage supply until the LED problem is fixed and there's a risk of shorting it to the low voltage side if a meter probe slips.

Hi Tony,

I wondered if you could help me with some problems I'm having with my build?

In a nutshell, I can't get the first stage power-up test to work. No LEDs light up and I have no current across R28.

To begin with, I think I've damaged IC4. I didn't scroll down the instruction page far enough and initially installed it upside-down.
When removing it I probably overheated it (because I melted DHT11).
I also damaged the tracks on the board, but I believe it's all connected okay (I made a solder bridge across pins 5, 6 and 7).

I possibly have a problem with D17. I can get the other LEDs to light dimly if I connect my meter in test-tone mode. It also helps me check polarity.
I can't get D17 to light. I also can't get D1 to light, but it may need more power for me to see it through my camera viewfinder.

Lastly, there's confusion with T12. I have version 1.11a and the assembly instructions say that T12 should have two legs. Mine has three legs, is that a problem?

I'll pick up another temp/humidity sensor today and also an LED to replace D17. I can't get a new IC4 quickly, but in another post you said the board should work without it.

I've double checked and re-soldered every component on the board, so there aren't any dry joints or incorrect solder bridges.

Apart from the obvious melted components, do you see any of the other points causing the board not to power up?

Thanks, Dale

Hi,

First check the current range fuse in your meter, I know it sounds silly but you'd be surprised at the number of times it's been the problem. D17 is only an 'on' indicator and isn't needed so don't worry about replacing it for now, it may be OK once the board is powered up.

It will work fine without IC4 just with less accuracy. They're a serial IIC sensor made by a few different manufacturers and sold under other numbers such as LM75, TCN75, DS75. The price usually reflects how accurate they are, the supplied version should be +- 1 degree C.

T12 will work with either 2 or 3 legs as the third connection is made by soldering the heatsink tab to the PCB, I just end up using whichever version RS has enough of in stock at the time I order.

That is a good point about the instructions, I've swapped the order the pictures are shown in. I doubt there are any V1 kits left to be built by now.

Hi Tony,

I checked the fuse with my other meter and it's okay.
I also removed D17 and checked it off the board. It's also okay. It must've been C5 that was drawing power from the meter.
The only temp sensor I can get nearby is a DHT22. It's bigger, but it should work.
I still don't know why I'm not getting anything to fire up.

It might be worth checking the voltage between the R28 pads just to make sure the power supply and USB lead are OK, I haven't had a faulty supply yet but once did have an o/c lead.
If there's around 5V across there then try temporarily fitting R28 and try powering up again. You've checked it for shorts so it should be OK.

I wouldn't use the DHT22 unless you can't avoid it, it's pin compatibe but quite a bit bigger and won't fit easily into the case. How badly melted is the DHT11? if it's just the plastic it might still work.

Hi Tony,

I don't know what happened, but it's working.
It could be that my meter just wouldn't measure across R28 correctly.
I did have another go at cleaning up some solder connections. After a good clean with quality contact cleaner (highly recommended), there were a couple of spots that looked a bit suspicious.
Anyway, I now have the nixies flickering back and forth. I just have to figure out how to get it to display a temperature value. Maybe it's not getting a reading of any kind. I'll just have to read the instructions!
I'll change the DHT22 back to the DHT11 and see what happens. I'll try the original IC4 back in again. If I have to get a new one of those, I'll get a new DHT11 as well.

Thanks for your help!

Hi Tony.

One more little issue.
When I assemble everything, the nixies just cycle through modes continuously.
The IR signal is being reflected inside the case. Waving my hand over it doesn't do anything at all.
Any clues?

Thanks, Dale

Hi Tony,

Never mind. I figured out what to do.
A small length of black heat shrink tube over the IR LED to direct the light straight up instead of bouncing around inside the case.
It looks great.
Excellent kit, Tony!

Can you post the overlay of the new er version PCB?

Hi,

I've added them to the first post of this thread.