Fixing the Space Station Toilet (Harris PowerCD)

A couple weeks ago I was at the tower making bad jokes about the liquid cooled EEV ESCIOT tube based Harris PowerCD transmitter being a space station toilet.

Really, it’s a three stall restroom, and today I got all three flushing again… and learned more about how freaking weird and scary *pure* deionized water can be.

First, here’s a questionable explanation of what’s in there. You’re looking at two separate liquid cooling loops. The external one which exits the cabinet at upper left circulates an ethylene glycol coolant solution (similar to automotive antifreeze, but nigh unobtainable outside of ordering it off Shamazon) between the heat sources and a set of fan cooled radiators outdoors. It’s circulated by an external pump station. I marked its flow with the orange arrow emojis. The internal one has a pump in the cabinet as it’s a closed loop within. The vertical accordion looking piece is a heat exchanger. Attached to the door on the left are two filters that keep the deionized (DI) water as pure as possible to keep its electrical resistivity high.

The supply manifold at the top sends the anode and collector water jacket water supplies to the tube cart around the front. The small line coming out the middle feeds the filters; you can set their flow rate with a valve up there. Everything finally returns to the pipe at the left that sends the DI water back to the reservoir on top. Now, have you noticed the middle finger emojis yet? Well.

Meet the Pinwheel of Despair.

In the DI water returns from the anode and collector are these Seametrics flow sensors. The pinwheel has magnets in two opposing vanes, and a Hall effect sensor screws into the recess seen at the bottom here. By measuring the interval between pulses, the transmitter controls can determine if there’s enough water flow… until the sensor breaks.

Now let me say this, I see absolutely nothing wrong with the design and build of the Seametrics sensor. It’s actually damn cool for what it is. No metal parts contact the working fluid, and it rides on a ceramic shaft and ruby bearings like a fine watch movement (and that wouldn’t even have ceramic shafts… Or would it?)

The Seametrics is even completely field rebuildable!

So, uh, time to be creeped out and amazed by mere water. In the picture of the cabinet you’ll see there’s one more sensor mounted horizontally in the glycol line. This never fails, as the glycol solution has some lubricity to it – that is to say it’s slick and forms a film that tends to isolate facing surfaces from direct contact, just like an oil would. The DI water, however…. No. When I got some on my hands, it felt really weird, almost more like I’d just rubbed them with a really cheap and nasty hand sanitizer that was stripping the oils and leaving behind sticky yackage. So let’s see what it does to those extremely hard, smooth bearings:

Hey wait a minute, that notch wasn’t there from the factory!
Unhappy Calamari

The bore of the bearing above has become egg shaped. This wasn’t even the worst one — that distinction goes to the one that was in the collector flow meter:


I wasn’t able to pull this one apart for further inspection but didn’t need to. You can see the axle right through the plastic — it chewed completely through the ruby bearing and started digging into the plastic. Funny thing was this one would work perfectly UNTIL the water temp rose to about 46 degrees C when I put the cabinet in Beam On (normal RF output state), at which point it’d abruptly start ticking down from 12.6 GPM to 10 and the controls would kick the beam supply off to avoid meltdown. After rebuilding both sensors on the DI water side, the flow readings come up the moment the pump starts and stay stable.

This is either success or impending zeeky boogy doog
now don’t tempt me to try to fix that old radar too

Want to read more about how damn weird pure water is? There’s a somewhat sensationalized (in their usual style and don’t even get me started on that Supermicro fiasco) article from Business Insider about the Super Kamiokande which is a massive subterranean neutrino detector tank lined with the stuff that physicists have had to enter on a rubber boat for maintenance. Just imagining what that’d feel like across a large area of skin makes me want to go rub an Aloe Vera leaf on my entire body.

Really it can kinda be summed up by this poor Chia Bob Ross that doesn’t look much like a Happy Little Tree. Fnord.

From a distant time

Transmitter sites used to be kinda different – it was not uncommon for them to be manned daily, if not outright equipped with an engineer in residence. Now they just tend to have weird ghosts and stuff. I’ve only ever seen the name O’keefe & Merritt on appliances in old transmitter site kitchens. Ok then?

Shitpost #3141592

In honor of whoever the holder of mysterious Dogecoin whale account is having made deposits of 420, 69, 420.69, and 3.141592 coins just to show off. (who the hell are you?)

Today I found out this mysterious BK Dynascan component tester/curve tracer was also sold as the Polar T-1000 or T-1200 so I finally have a manual! Woo.

And with the posting of Milkwalker, I dedicate the rest of this to shitposts and random memes.

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How cold did this even get??

I keep staring at this photo someone sent me on Facebook in amazement and confusion:

I’m a little confused as to whether this is from a weep water system slowly running water through the lines to avoid freeze damage between the equipment room and the gantry, or if it actually attempted a wash cycle at like… -20F or something… and just became a giant aesthetically pleasing mass of colorful ice. Either way, it’s beautiful, but not very useful until temperatures rise and possibly a few blown out hoses get changed.

2014 Subaru Forester Fan Relay Diagram For The Rest Of Us

I hate cars. They’re just giant expensive pieces of cost-engineered crap that cause horrible anxiety. Apparently, the service manuals for them pile confusion on top of that as well.

I don’t know WHO this diagram was designed for, but it was clearly not to be seen by human eyes and minds. OUCH.

From the factory service manual:

Ow. My brain. I mean— this IS a schematic, but… ow.

I redrew it to make it easier to understand and follow. The scanner in my office doesn’t understand the orange I highlighted the wires that should be energized off +12V ignition switched and turned it kinda beige-ish. Whatever.

I omitted the “Through Joint Connector” points shown here. I have no idea what those physically are – my best guess, being that I didn’t see a bunch of connectors in the circuit, is that they mean those are internally connected on the ECM harness plugs or in the fuse/relay holders.

Fuse F22 is a horrible mystery. Check it for yourself – the factory schematic suggests that the ONLY thing it powers is the “Sub Fan” relay coil, not the actual fans themselves. Why? Actually WHY ANY OF THIS???

In general I have a love/hate relationship with any cooling fan control system that incorporates a low fan speed for pretty much no good reason, and by that, I mean, I love to hate every single one of them. I’d rather hear a single loud fan cycling on and off than knowing that the whole control system is a ball of spaghetti wrapped around a meatball of ticking time bomb complexity. I also love that when I was trying to figure out how this works (the manual doesn’t really explain it) I found that there’s a reasonably useless possible state for the system of running one of the two fans.

I’m having an issue with one of the relays causing one of the fans not to spin. Specifically, it’s the “main” fan on the driver side, suggesting an issue with Main Fan Relay 2, which I was able to get the cover off of and look around inside… it looks like it’s gotten hot and both contacts looked pretty raunchy. It is not the logic state that you’d get to if the ECM were to ground pin B12 and not B11, which would cause the main fan to run only, at high speed.

So here’s the adventure so far—-

I’ve been through one radiator fan which might not have even been bad in the first place, though it spins kinda rough and probably needed to be changed even if it WAS functioning (that being the case, it may have been drawing too much current and pitting the relays).

Pictures from this silly adventure ahead (let’s keep this post from making the main page a kilometer long!)
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