power supply to the people

As mentioned before, one of the critical bits missing from my vacuum chamber purchase was a power supply/controller for the TPU 110 turbomolecular pump. Having looked through the pump's manual, I found that it called for a Pfeiffer TCP 270. Once again, eBay was my first and last stop. Perhaps somewhat surprising, there were quite a few available. I know this particular model covered more than one model of pump, so maybe that explains the selection available. The strange thing I've noticed as of late is just how wide of a spread in pricing exists when searching for specific items. One seller might be asking $30, while another is asking $1000. Sometimes the more expensive items are unused or rebuilt, but typically that's not the case. Nor is it necessarily the case that the more expensive items are in better condition. Often even those are listed as untested and sold as-is. Perhaps those sellers "know what they got"; in other words, something likely priced too high to sell.

Once again I opted to go the frugal route, and found a power supply that appeared to be in decent condition, with a "or best offer" option. Keeping with my purchase price modus operandi, I offered an amount that would place it slightly below $100 after shipping. My offer was accepted and I soon received it at my doorstep in a well packaged state.

Huh. The corner was bent, the gauge needle sat almost midway up the scale, and the "pumping unit" button was stuck pushed in. Who knows when the damage was sustained, but given the way it was packaged, it wasn't during shipping. At any rate, I didn't care about the corner or the gauge, but obviously something would have to be done about the switch. I popped it open to take a look (actually, I did that before I even noticed the switch)

Pretty good cable management, and nice old-school wire lacing 

Yep.. The switch took enough of a beating to crack the plastic nut. Removing the nut revealed access to a pair of retaining clips for the switch face. This is how custom switch faces are installed, as well as how the indicator lamp is replaced. I found that the switch operated just fine without the face installed, but there was nothing visibly wrong with the face either. After reinstalling it and toggling the switch numerous times, it seemed to work ok, but every once in a while it would bind slightly, or it wouldn't latch when trying to engage (it's a push-on push-off style). It was usable, but I decided to swap the two switched, especially considering my pump didn't have the heating jacket option anyways, so that switch would go unused.

This was a great opportunity to try out my new soldering iron...

Behold the power of bacon! Er, Bakon. Bakon 950D to be exact. Several years ago I donated my soldering station to the local makerspace, which was fine because I did all my soldering there anyways. Having decided to build up my home lab again, I was in search of an iron. I fell in love with the pencil design of the Pace ADS200. I came so close to pulling the trigger on buying one, but ultimately I decided against it. Realistically, at this point in time, $300 could buy me a decent iron and a bunch of other things. So then I started gravitate towards the TS100 or TS80, but despite the favorable reviews, I really didn't like that grounding the iron was kind of inconvenient. Next up was one of the many variants of the KSGER with a T12 type tip. But there were a bunch of different ones, made by who knows how many different manufacturers, with different power supplies, using different microcontrollers for temp control, and none inspiring too much confidence. Then somehow I came across the Bakon 950D (listed as Feita 950D on Amazon). While I'd probably prefer a unit that uses T12 tips, this one uses T13. Reviews were good, power supply design was proper with name brand active components (the caps not so great), and actual tip grounding. Per this thread, the unit drives the tip with a power of ~42 watts. The original poster of that thread also modified his, bumping up the output power to roughly 66 watts. Ultimately, it was his opinions of the iron that made me choose it. I might eventually replace the included pencil with something that uses T12 tips, and perhaps an almost ADS200-like finger to iron tip distance. 

So the unit might not look very impressive, with it's simple 7-segment displays, two push buttons, and it's wannabe laptop charger enclosure, but I was immediately pleased it during my first go. I've never used an iron with a directly heated tip, so that was game changing for me. Not only does it heat up significantly faster than anything I've ever used before, but it transfers heat to solder joints incredibly quick too. So here's the kicker: I bought the iron, which included 6 different tips, for a penny under $35. Incredible. I'd definitely recommend it to anyone in need of an iron, but doesn't have the budget for a Pace, JBC, or a higher-end Hakko.

Back to the pump power supply. Scrolling through the pump's manual, I came across this little bit:

Uhhhhhh.....

Ummmmm

Ehhhhh

Well two can play that game!

Problem solved.

Maybe not that easy, but close! This looks like a job for........

The ol' universal hacking device chip.

Dropped right into place. No soldering required. 

But all that solderless work was for nothing, because.....

Well that was easy! I was actually aware of this before ordering the power supply, because most of the ones for sale were set for 1000Hz, with the few 716Hz units tending to be more expensive. Even before learning about that resistor, I figured the difference between the two would be minor. Luckily it was much simpler than I originally assumed. 

TODO: change the electrolytics -- Just in case. Clean the dip sockets and IC legs. They look slightly corroded.