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Time, BitX 20, PCB Laminator and an ESR Meter

    Well, I've done it again.  I've gone a really long time without updating.  What worked on in the mean-time? Mostly small projects, minor modifications to things, repairing broken stuf, a hackerspace (which didn't make it), etc... Maybe I will write about some of that later.  I'm not going to make an effort to catch up.  Last time I said I would write about all the stuff I missed, that just made me not want to sit down and write at all and contributed to the latest huge gap.

   I have been working on one large project.  Last May I bought a Hendricks Kits BitX 20 kit.  I've been slowly putting that together a bit at a time and documenting the build on YouTube. For now it's a pretty much stock build, just follow the instructions with few minor exceptions so it may not get a project page. I do intend to do the varactor mod and the voltage regulator mod.

  I don't expect any surprises from the varactor mod.  I am interested in comparing the before and after w/ the voltage regulator mod though.  I'll probably test it with my heat gun.  It's not that I doubt that a voltage regulator is more stable than a lone zener diode.  I just wonder, did Farhan chose the zener with it's drift in mind? Something to compensate for an opposite drift elsewhere in the circuit?  I've been studying a lot and am learning more every day but I can't yet answer that by just looking at the schematic.  I'll make sure to test it and get that on video.

   Last night I had success with a much smaller project.  I modified a laminator for use with PCB iron on transfers.  This was Aliesha's laminator. PCBs are usually thicker than paper and lamination packets so they don't always fit.  When I found that PCBs do fit through her old laminator I bought her a new, nicer one so that she wouldn't care if I took hers and wrecked it. I didn't want to buy my own just to find that PCBs don't fit, nor did I feel good about modifying one mechanically to fit thicker stuff.  As-Is I could get transfers to work but only by first heating the bare board in the oven and then passing the board through the laminator many many times.  It needed to be hotter!

   Instructions I found on the internet for doing this had two steps. First, either replace or bypass (if you are brave) the thermal fuse. Second, cut the wire to the temperature sensor and add a resistor in series.  This tricks the electronic temperature sensor into thinking the device is cooler than it actually is so it gets hotter.  That sounded easy enough.  Luckily before I ever took apart the laminator I found another page with a slightly different kind of laminator.  This one instead of measuring a resistance just had a mechanical thermostat that acted as  a switch that turns off at a given termperature.  It turns out that is the kind I have.  This was really easy, i just had to replace the regulator with a 170°C one. (and the thermal fuse too of course). 

   Those aren't exactly things I can find in the local Radio Shack but they are no problem at all on EBay.  A few bucks and a long wait for over-seas shipping later and I had a bag of fuses plus 2 thermostats.  Everything fit right in place of the old parts like they were meant to go there.  The only tricky part is you have to crimp the fuses to the wire.   Solder could melt!  I used the bodies of a couple of crimp-on spade connectors for that and just broke the spade part off.  There are a couple of protective sleeves that go over the fuse and wire, they were kind of tricky to slide back on, over the crimps , especially because it has to bend to fit.  After a couple tries I got it though.  There was also heat-shrink tubing over the old fuse leads and crimp connectors.  I guess it must be a special high-temperature variety?  I didn't even try to replace that as I doubt I could get it over my sloppy crimp connectors.  I also doubt my regular heat-shrink tubing would hold up well in that hot environment. I don' t think that this will matter since the whole thing goes inside a couple of insulating sleeves that should protect it from shorting just fine.

   I tested it out with the board design for a Capacitor ESR Tester that I found on the Internet and would like to build.  I added the author's call, VE7IT and a link to his page to an empty area of the PCB design.  Unfortunately I forgot to mirror image the text so it came out mirrored.  I also made no attempt to conserve board by lining the transfer up with a corner.  I just plopped it in the middle, slightly crooked because I was in a hurry to see how my new PCB laminator worked.  Maybe i will scrub the toner off and redo this one before I etch...

PCB Laminator w/ old, new parts and it's first PCB
Here's my new PCB laminator with the old parts on the left, leftover new parts on the right and it's first PCB in the middle.

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