Crack & Speedball -Wrong resistance and Voltage readings

[alesi]

I have gone through the solder joints on the large pc board again. No luck.
The voltage readings for A3 and A8 are 1 (one). T1, 2, 4, 5 - ~195.


Appreciate any help.

 

[Paul Birkeland]

Bottoms of the boards was meant to be bottoms of the small PC boards.  We'll deal with the large board later.

Do you get 1.5V at A3 and A8?  (You may need to turn your meter range down to see what the exact voltage is.

-PB

 

[alesi]

I just realised that I mixed two different solders for the boards. Unfortunately one was nearly 20 year old which was till in my toolbox, might explain the excessive flux.
I spent some time with desoldering  braid and alcohol to clean as much as possible and apply the correct solder again on all boards.

Unfortunately the voltage readings have not really changed Now it is about T1,2,4,5 ~ 199
A3/A8 ~1,6

 

[Paul Birkeland]

Tell me about the 20-year-old solder, what does it say on the roll?

 

[alesi]

Well, once I realised it I binned it straight away. So I can't tell what the specifications were.
I remember using it partly for the speedball addon only. The rest was 60/40.

Used this for Crack and it did work
https://www.amazon.co.uk/gp/product/B000LFVHK6/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

And this for the speedball (with the ancient one)
https://www.amazon.co.uk/gp/product/B002L5Y8R8/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

Are there more ways to test the components?

 

[Paul Birkeland]

I think the ancient solder you used might have been solder for plumbing.  The flux in this solder is mildly conductive, and would explain some of the issues you're having.  Unfortunately, since you threw out the roll, it will be very difficult to tell, but I would start by cleaning all of the flux off the PC boards.

 

[alesi]

Thanks for your help.
In case you have few other ideas to debug the issue I'll call it quits then.
I have spent a few hours this morning to remove the old solder, clean up all the flux and re-solder it again.

 

[Paul Birkeland]

Yeah, that plumbing flux really likes to stick around in FRP (PC board and terminal strip material).  If I had your Crack on my bench, I would be putting in a new Speedball.

 

[Doc B]

We had another kit on the bench last month that had an excess flux problem. I thought I could getaway with replacing just the board that had a short on it from the flux. When the customer got it back a noise started up, from another board. We took it back and replaced that one too. So it might be necessary to replace your boards.

If that is the case you might have nothing to lose by pulling the boards off, running them through a dishwasher cycle and reinstalling. Might help, might not.