Only 11,45v on TP2

[jeroenParticipant]

Hi Guys,

Following the tutorial on youtube to put together my NCM109 v1.1 board I managed to get all the parts installed. Although there were a few minor differences in tho components I received and the one’s in the video I got it all soldered on the board.
The biggest difference is U4. Which, according to the video should already be installed but instead I needed to solder it on my self. It is a 3547 L3478 MA which also needs to be soldered 90 degrees rotated as compared to the video.

Measuring the voltage between TP0 and TP1 gives me 5v which is correct. If I measure over TP0 and TP2 I “only” get 11,45v. No matter what I do with the variable resister R17 it stays on 11,45v.
Do you have any clue to what is wrong here?

Jeroen

[mnadlerParticipant]

I too have the same issue, only 11.26v between ground and T2. I had the same issue with the U4 chip, and feel confident it’s properly installed, as the pitch between leads wouldn’t have allowed to be soldered the other way.

Have any thoughts?

[jeroenParticipant]

I just found out the problem. Although everything looked fine I noticed pin 8 of U4 was not soldered as good as the other pins. So I re-soldered the pin and voila, 180V on pin TP2.
I am now soldering the tubes on the board and will post a reply here if all is working fine.

[mnadlerParticipant]

I inspected my U4 soldering, and that’s not my problem.

[jeroenParticipant]

My clock is working now. Next step: Building the case 🙂

[mnadlerParticipant]

I found a cold solder joint on R16, all good.

[yaelblazeParticipant]

Does it haappen for you guys that Q1 is really hot ?

[Author]

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