The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)

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awemawson:
I started out this morning with the intention of removing the wires from the Klippon Block for input array #3 one by one, and numbering them and replacing to avoid confusion. I had the choice of cutting off the boot lace ferrules, slipping on small number sleeves and refitting a bootlace ferule, or using a larger diameter number sleeve that would go over the existing ferrule, and hold them in place with clear heat shrink tubing. I choose this later approach. The replacement Klippon block isn't due until next week.

By the time I got half way through the process I thought, blow this, leave the wires off and see if you can attack the Klippon block with a soldering iron. Someone on another forum had told me that the orange plastic of the blocks is in two parts, the sides clipping together, and if unclipped the PCB is released.

So, all wires off, and released from the DIN rail, sure enough with a bit of persuasion the sides came off letting me see the solder side of the PCB for the first time. To my amazement every single pin of the 37 way Sub D connector had a neat little skirt of solder about 1/2 mm off the board - the whole lot were dry joints :bugeye: So the 'solder to pin' junction had stood the test of time, but the 'solder to PCB' junction had failed. I assume that these were flow soldered originally - perhaps the PCB cleaning wasn't up to scratch :scratch: (But the joints for the terminal blocks were fine)

Careful application of a bit of flux along with flux cored solder and soldering iron, and I remade all the joints. All passed a continuity test so I re-assembled the block, re-wired it in the machine and crossed my fingers.

All was well, she fired up like a champ and passed the tap test ("Tap with screwdriver handle in the manner of a reasonable man")

It does beg the question what is the state of the other four of these blocks - but then, I'll have a spare arriving next week :clap:

This exercise did at least give me an excuse to try my new Chinese "Heat Proof Silicone Soldering Mat", and I must say it's actually pretty good - saves my desktop drawing surface, and is thick and pliable enough to stop things skidding about as you work on them.

nrml:
Is there enough wriggle room to pull open the other blocks for inspection without disconnecting all the wires? Isn't it worth sorting out while you are still working there for future peace of mind?

russ57:
Is that soldering mat like the silicon BBQ/grill mats? Although direct from China might be cheaper anyway..

Russ

awemawson:
NRML: in a word no, and then yes in that order!

The DIN rail that they mount on is right at the top of the cabinet, and the connected wires are too short to get the unit off while still attached.

However I do intend to work my way through them starting with the extreme left one this morning. Some are quite sparsely wired so should be easy, but #5 at the extreme right is fully populated so will be time consuming.

Russ: not seen the B&Q mats so can't comment. This was £11 inc postage.

awemawson:
So I cracked on and attacked the leftmost Klippon block - IP1 - moderately populated with 14 wires needing labelling and 5 pre-numbered that need mapping.
It took two hours end to end and thankfully all tested OK on re-assembly. Oddly there was a link on pin 16 but the PCB track looked OK and tested OK. The soldered joints didn't look too bad but I re-did them anyway and also left the mystery link in place - maybe the track has a hairline crack?

Can I face doing another one just now - mm - have a coffee and a think :coffee: :coffee:

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