Another PTek. Another questionable combiner. This one doesn’t even make any damn sense. I’m scared to open up the top of the transmitter to find out why it’s wired the way it is. The resistors are sitting on top of that hand cut piece of random PTFE and will cause a fire if they ever dissipate any significant energy. This is inside an FM2500PS transmitter.
This is a two port Wilkinson combiner that combines together the output of the left two pallets and the right two pallets. Why it’s floating on the thick PTFE slab, I cannot understand— these resistors appear to have the terminal configuration in which one lead of the resistor is the heatsinking base, and the other is the solder tab which just passes right through otherwise. WHY IS THIS BOTH INSULATED FROM AND ELECTRICALLY CONNECTED TO THE HEATSINK??!! Basically, what WILL cause this combiner to blow chunks would be any imbalance between the left and right sides of the transmitter – a single module failure will roast the entire rig. Catastrophically. See video below.
The lower line from each side goes to the start of the harmonic filter network, where they are just unceremoniously smashed together. This is… about the caliber of a badly built CB amp.
Dare I open the top and look around or have I suffered enough torture already??
(edit: yes… sadly I did!!!)
Page spam cut— click to continue. If you dare. I warned you, and Alex Hartman always warns ME not to open these transmitters and look around. But I do anyway. Then my brain hurts. ARGH
Continue reading »
At work we have a rented F-150 to get up and down the mountains. I was going up to one of our sites, nearing the summit, when I smelled a burning plastic/rubber odor. I opened the hood (easier said than done– the placement of the safety latch is, to use my late uncle’s words, Kardashian) and found the cause after about a minute.
Behold….. Ford wiring.
So I’ve been under the hood of a few modern vehicles. All of them except this have the wiring harnesses protected by plastic tubing. This… uh, they just threw a lot of tape on it.
Interior: they used some kind of vinyl tape instead.
The burning smell was a loose piece of tape from the harness on the right hanging down into the manifold. I removed it before taking the picture and buried it in the sand because it was actively on fire— it had glowing embers at the end.
What the fuck, Ford?
Incidentally I’m mad at this shitty truck already. It gave me a bloody nose. See, they put this weird aluminum roller in the seat belt buckles that serves only to make them insanely heavy. As I got out of the truck, the retractor brought it up at unnecessary speed to meet my face with an audible CLONK. I’ve seen the same buckles in Kia and FCA vehicles, but they are not anywhere near as heavy (the roller is hollow I guess). The roller makes no sense at all, it doesn’t turn and is loosely mounted. I’m guessing they did this to reduce wear on the fabric? Funny how my Subaru doesn’t have this and there are no signs of wear to the fabric so…. Uhhhh??
I could go on about how much I hate that steering wheel in the background but I’m out of shitposting juice
I always used to wonder why every time I worked in a radio site I’d find the transmission lines going through the entry panel just goobered in there with silicone sealant or spray foam and the unused pieces of the Microflect / Andrew / CommScope / insert today’s name of the conglomerate cable entry port system lying around unused
Now I understand why and my arms and hands and back and legs all hurt, hours later
Woop Woop the FUCK POINT has been reached, this is as good as I can get this one. You just can’t get these things together if the cable doesn’t wanna go through straight.
I’d seen these photos of the Mt. Shasta Mall food court….
But apparently someone thought it’d be a better idea to throw that beautiful thing down the grinder and cut it off with the blank wall of an Ulta Beauty store.
Even the Orange Julius is gone in favor of yet another SalmonellaWay.
Press F to pay respects.
The contact that turns on the brake light, turns off cruise control, and triggers the solenoid that lets you shift out of park got all pitted! Ewww. Needless to say this was a show stopping bug… but it died at a gas station in walking distance of a Walmart where I was able to get some CRC QD cleaner and 2500 grit sandpaper and burnish it back to life. Here’s the before state. The contacts are actually proper silver buttons and the switch can be disassembled to clean it.
What a right mess though.
Not sure why the CRC QD cleaner turns my skin all weird looking like that.
The switch has a Nissan logo on it so I’m guessing some Nissan model out there in addition to the 2014-2017(?) Subaru Forester have the same thing.
Upon having the strange experience that a new supposedly frequency agile PTek would only work on half the band (seemed almost like an exciter unlock or something when I tried to dial in 107.1?) I decided to look at the exciter card to see if there’s a tunable tank coil or something
I wish I hadn’t now
SCA and composite inputs, J9 and J10 respectively. C66 lowpasses the composite sorta by shunting everything above an unknown frequency to ground. C65 highpasses the SCA, it’s in series. The two combine at fixed yet frequency dependent levels and go down that via near C63 and R33. U7 under the board is a voltage regulator. J1 is the RF out and L1 is the DC feed to the power amplifier just out of frame.
Yeah just go right ahead and stuff the audio inputs right on top of the RF out. No big deal.
Full view of the card. The DDS is at upper left.
Think you can get away from having your audio run across the butt of a voltage regulator by using the XLR jacks? No.
The trace going down the via next to R81 is one of the audio channels, and it runs right under the header connector for power and data to the board.
A word on this PA. This is a new LDMOS transistor from ST Micro. As such, its dissipation is really low, and it basically gets heatsinked by the leads and traces. Here’s the reference design…
What you get is significantly less copper. The big ground planes that’d soak heat away via the source leads are just not there… so a weird block thing was sandwiched under the board and I don’t even want to look at this any more
The stereo generator used to, in earlier designs, be based off a DSP that I’d heard they couldn’t get anymore. This stereo generator is what I could best describe as “deconstructed BA1414 feeding a high speed ADC”. I’m guessing the two PICs are used for timing generation and the 8 bit ADC, U8 / DAC0800LCM is probably used to generate a sine wave from a lookup table or something. conspicuously absent is any sort of audio filter to roll off program content above 15-18 khz, if this is present the generator flips the hell out. It’s a living nightmare on green circuit board. Gaaah.
Side note– the BA1414 I mentioned above is a chip made by Rohm which is used in a lot of really cheap little FM transmitter baubles and produces TERRIBLE output. It performs stereo multiplexing using a couple of poorly filtered square wave oscillators that are mixed with audio.
This hilarious oversight found on an Allmand Maxi-Power 25 generator. The engine is a small turbodiesel utility engine made by Isuzu. The whole thing was assembled in Japan by Hokuetsu Industries….
… who hopefully sell a special bendy straw funnel.
Here’s the oil fill cap. The drain and filter are very easily accessible from the other side. But the filler… Oy!!
Above, the exhaust pipe.
Perhaps you can get in from the other side? …. Nope.
Look at that cute little tangerine sized turbocharger!
It seems to be like they could have added an access hatch above to make it easier, but yeah… Bring your Crazy Straws….
Newly remodeled store, just… nauseatingly confusing layout. Maybe all the fresh carpet adhesive smell is what’s nauseating though. Oh yes, it’s CARPETED, which will guarantee it reeks of filthy carpet after a few months, like a CVS store does.
Central Illuminated Sadness Cavern (TM)
Slotting fees are nothing new in retail. A company must essentially pay rent to a chain store in many cases to get their product on the shelf, and must pay more for certain features such as end cap displays, shelving at eye level, not having the store’s own generic of the product displayed next to it— in this case certain brands of kitchen products paid to not be plunged into DARKNESS. My visual estimate says 2 f/stops down when you go back to the wall. Amazing.
And this isn’t even one of the layouts with the new “River” concept, which is a curvy path from the entrance that will parade shoppers past promoted items…
Funny how this layout in particular reminds me of the one that took Sears to its grave. 😉
As the Carr fire continued in Whiskeytown, we had no power to our site but a remote control continued operating on the generator. The final data I got from it showed 140F stack temp above the transmitter and 122F at its chassis.
The cause: burnination.
Thanks to Matt at Valley Industrial Communications for these pictures and for being a far braver soul than I…
Hey look, it’s still got a roof!
Continue reading »
I’ve seen this on the Internet before but never thought I’d see a brake rotor this bad in person.
The (Oh, oh,) O’Reilly…. Auto Parts (Yow!) here in Willows just had a customer bring this in when buying new parts. Daaaaaaang!
Or should I say, YOW!
The O’Reilly Auto Parts jingle/radio advertisement music bed I’m referencing is a severe earworm. 😉