Thursday, 22 January 2015
Dead Simple Power Supply
At work I'm quite spoilt, there is an abundance of equipment in the labs, and if I need, I can borrow something for home use. Very handy when ding something specific (like the thermocouple I used here) but it comes with a down side.
If I realise I need something, it means dropping work for a few days until I can borrow the equipment (if it's in use at work, I can't have it until it's free) and as I catch the train, it also means bringing the car in if it's too big to fit in my backpack.
When it came to powering my projects, I have a very basic dual rail Power Supply (I built one just like in in Uni, tortured it to death over the coming years by running a car amp from it in my bedroom) that I inherited from a guy-who-got-it-from-a-guy-from-a-garage-sale deal.
The updside: It's got dual isolated rails, 1.25V to 15V range and 'up to' 1A output.
The downside: It's so old the pots are scratchy, so setting an output voltage is a chore, and there isn't any current limit. And you need to whip out your multimeter to set the voltage / measure the current in use.
So I got cracking on this:
Wednesday, 14 January 2015
Cheap and Cheerful!The other day I scored a TV to fix. It also came with a remote that needed some attention. The volume buttons didn't work nor did 'Channel Down'.
This is usually due to the conductive pads on the rubber membrane wearing out. You can buy conductive paint to rejuvenate the buttons, but that stuff isn't cheap, and probably isn't lying around when you want to fix something RIGHT NOW.
So I thought I'd share a little trick I know.
The Patient, Tools and Operation Table.
Sunday, 11 January 2015
Thursday, 8 January 2015
Sentimental IssuesBack in my Uni days, I bought what I thought was a pretty sweet soldering station - the Micron W/2172. If I remember right it cost about 4 weeks worth of part time wages, and I think it was worth it - it's lasted about 20 years so far.
But, there are issues. I can't find a supply of new tips for it, and the last good tip is a conical one. So it was put away in the cupboard and I upgraded to a Hakko 396 station.
Then I got to thinking... both stations used a 24V supply to heat their irons, so how hard would it be to graft a 907 handle into the Micron station? It would also be handy - I could load the Micron station with a big chisel tip for when you need a lot of thermal mass, standardise on one set of spares for both stations, and avoid having to swap tips on my Hakko all the time. WIN!
Will It Work?
There is a lot of information out there about the Hakko 907 handle, and this topic on the EEVBlog forum was exceptionally helpful. The important point to take away is that the 907 handle uses a thermistor to measure it's temperature.
If the Micron does the same, it should be a simple mod.
Take it Apart!
So, I whipped to cover off and started to take a look.
Friday, 5 December 2014
Some Free Advice!
Back when I write about my failure to build a current limiting circuit for my Alarm Panel Interface, Zega was kind enough to offer me some advice.
Long story short, half the oscillations I was chasing in my limiting circuit were due to my quick and dirty Constant Current Load.
Here's the Problem...
Thursday, 4 December 2014
Giving BackThe other day I was looking at my blog stats, I was surprised to find that my KiCAD posts were linked to, where someone was wanting help converting an Altium reference design into KiCAD.
So, I thought I'd help out - here's the reference designs, converted to KiCAD PCB.