The Craftmans Shop > New from Old
The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
PekkaNF:
Jep. No system works for all ocasions and I often run out of hands, those two extras help.
https://www.bot-thoughts.com/2013/01/easy-pogo-pin-test-jigs.html
https://blog.adafruit.com/2013/07/08/using-pogo-pins-to-shrink-6-pin-isp-connectors/
There are some easy solutions for batch of boards, but to test economically single board on hobby setting needs soldering - eventually.
awemawson:
My 'Hot Air Re-work Station' arrived by post today. I have to say that I am impressed with what you get for your money. (£36.67 plus post - total £44) and it seems quite well made. My photo doesn't show it but a temperature controlled soldering iron is included in the kit that plugs into the base unit.
A bit busy today but I had to try it out. I removed a resistor pack from the original RAM card that got dissolved, and it seems that the pack is in good enough condition to re-fit if needed, so a good result for a first effort.
I need to research what temperatures to use - the solder melts below 200 deg C but most on line sources say use 250 which is what I did. But what temperature can IC's stand and still survive?
awemawson:
I got a bit more time this afternoon, so decided to remove at least one of the suspect 74HC00D SMD chips to find why A12 wasn't floating 'high' as expected.
So - first chip out and I powered up and A12 is still 'misbehaving' - so then I took the second chip out as A12 connects to two gate inputs on both chips. Argh - A12 STILL misbehaving :bang:
OK what's going on here :scratch: Well it turns out that the termination of these five control lines is not a simple 10k pull up to 5 volts, but also a 10 k pull down to 0 volts.
All five control lines pull up to 5 logic high and down to logic low with a 1K5 resistor so it's all been a none problem - how very familiar !
OK something else learnt, AND practice using the SMD hot air gizmo. I decided to re-install the two chips and darn me they have survived the exercise and still work!
But I MUST sort out physical connections to this board - pushing female jumper leads onto the edge connector is very unsatisfactory - I must knuckle down and solder up the bread board that I now have.
Still - happy that I can not only remove SMD chips but also put them back and they still work :clap:
awemawson:
So why haven'i I done the breadboard yet?
Well I've been waiting for inspiration to get over a little 'problem-ette' - the bread board designer certainly laid it out to take a DIN41612 three row 48 pin socket, but only the outer 'A & C' rows of pins are brought out to the body of the board - row 'B', the centre one, is all on it's ownsome lonesome and will need jumpers, which cannot be on the component side if the socket is to sit correctly.
OK it's only 16 links - 32 soldered joints - but I've been trying to work out ways round it ! Years back I'd do links like this in 'self fluxing' enamelled copper 'magnet wire' where a good hot soldering iron would volatilise the insulation, but I'm not sure if I have any left - time to go hunting in the wire stash :lol:
The plan is to have the Arduino fixed to the breadboard as you may well have gathered from the picture.
. . . I'm off wire hunting . . .
awemawson:
Well it seems that I have :thumbup:
Buried in a dusty box I found two rolls of self fluxing wire - one rather too thin and the other rather too thick - oh well 'it'll do'
Iron needed cranking up to 475 degrees C to effectively remove the enamel, but it DOES work !
More experimentation later I think
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