So I was looking for a picture I took a while back of an audio mixer and searched Google Photos for “mixer”. First result?
So I figured it was a good time to reboot the ELC automation server for Good Day Sacramento and one of my coworkers has wanted to braid my hair ever since I dyed it all rainbow. Her daughters aged out of letting her braid their hair and she missed doing it… so she braided my mane while ELC juddered back to life. The result is amazing.
The shirt I’m wearing is one I drew on with glow in the dark fabric paint. I wasn’t sure at first if I liked how it came out until I saw how it looks actually worn. It just didn’t look as nice lying flat. I’m gonna have to put a blacklight up at the station somewhere for…. reasons.
Ever seen a TV live truck on scene? Well, if you have, chances are you’ve noticed a thing on top that looks like the top of Crow T. Robot’s head on a tall extendable mast.
What you’re looking at is a foldable microwave dish that can be used to send video from a live shot back to a fixed receiver site that forwards it to the TV studio. At the bottom of it is a remote controlled pair of big chonky motors that let you, standing on the ground, pan or tilt the dish to get it lined up with the receive site so the station can see your live shot coming in.
One of ours got stuck in the up position so I needed to pull it apart and fix it and I intended to take some more pictures of the apparatus as it’s kinda cute – it has two big Bodine gear motors driving worm screw drives via little drive chains, and has limit switch cam assemblies to keep you from going past safe travel limits on the thing.
I found the issue pretty soon after figuring out how to open the weird chassis of the dish motor, which opened vaguely like a milk carton – a hinged milk carton made of sheet metal. I’ve never seen anything quite like that and have to give them points for originality, though, if you had to get in there and the dish was stuck in a position other than straight up, you’d have to disassemble the entire shebang from the sides and take the dish off and everything and eww.
Thankfully, this was stuck straight up, and Tina caught a couple pictures of me working on it after I got it open:
But then the gloop went off.
See, what happened was one of the motor brushes got stuck in the brush holder and wouldn’t advance as it wore down a little, which caused the motor to stop working open circuit. I pulled it apart and managed to get this picture before I realized….. whoops, the armature of the motor and its pressed on bearing were the only thing holding the gloop in. You can see the brush on the right still wedged back in the holder where it can’t actually touch the commutator:
The gloop I refer to is a particularly foul, stinky, sticky, syrupy sort of gear oil, almost all the way up to being a grease in viscosity, but just low enough in viscosity to allow it to make a huge mess in short order. This is the second time I’ve run into it on Bodine motors – there’s no externally visible sign of it having an oil filled gearbox, no fill/drain screw or plug, nothing. You just get a terrible surprise if you dare separate the motor from the gearbox. GLOOOOP.
A fair amount escaped and got all over everything, but there was certainly enough left in the gearbox immersing its guts that I don’t feel I need to disassemble the whole thing and try to refill it. Nah, it’s just a learning experience… AGAIN…. BEWARE THE GLOOP.
Otherwise it will get the song stuck in your head. That song never leaves…. not that it ever has to.
A carefully phase and chroma level adjusted message from your friendly local non-binary broadcast engineer.
The resolution on this Panasonic BT-S901 shows just how spoiled I have always been by the nicer resolution on JVC and Ikegami monitors. This claims to be 300 lines but pretty much looks like a RGB microwave oven door. :3
Down in the river delta this morning, a circuit breaker went TWANG, and eventually, an engineer went HHHHHHHHHHHHHHHHHHHHHHHHHHHH.
The Space Station Toilet transmitter dumped one cabinet. While I was waiting for one of my coworkers to get there on site and see why it wouldn’t come back up, the first order of business was to remote in and change the combiner mode so the dead cabinet was no longer in the system (which caused a large amount of power from the other two surviving cabinets to get dumped into the combiner reject load due to the mismatch).
The Space Station Toilet is an older generation of Harris transmitter using their old eCDI user interface system. Their newer stuff uses a weird looking but far easier to use interface which does not require FECKING JAVA (!!!!) and has a nice block diagram sort of layout. You can see it in action here on a HPX series FM. Since it’s natively designed to work great on touchscreens, the newer GatesAir TV rigs come with a cute little pull out shelf where you just set a generic tablet PC in there to use as the front panel UI. But uh, eCDI is a confusing dated looking mess, and its design contributed to an… incident.
I went in there, took the dud cabinet out of the combiner on the mode tab, then noticed cabinet 1 had no IPA power or beam voltage. I decided since it was not working correctly to switch it back to BG heat until it could be serviced.
BG heat is kind of a keep warm mode that leaves the ESCIOT tube filament on at reduced voltage, and I think also leaves the ion pump on. It’s basically a warm standby that keeps the filament ready to go, and helps maintain the hard vacuum while the tube isn’t actively online. Well….
Two minutes later I got a call from our director saying “hey, we’re off the air, and I think it’s because you did the same thing I did…”
Sure enough… Note the two screenshots. See the difference?
Blink and you miss it. It’s not the difference of which button is selected at upper right.
The issue is, if you’re in the HPA tab at the bottom, the Beam On / Standby / BG Heat / Off buttons affect the state of one HPA cabinet, as selected by the 1/2/3 buttons. If you’re in the TX tab, guess what they affect the state of….
KERPLUNK. FLUSH. BEAM OFF. ZERO WATTS. ENJOY BUSH’S BAKED BEANS.
Beans. Mmmm, beans.
The day this thing is to be decommissioned I want to see what happens if I fill the cooling system and high voltage power supply cabinets with beans and turn the transmitter on one final time. BEANS ON, BABY! Mwahahahaha.
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.
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:
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.
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.
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?