One of these days I’ll fully fix the web server issues with this site. Today is not that day but I do like the result of changing the LEDs in these kitty eared headphones to near-UV colored ones (similar to NTE’s “Super Purple” color). Well I fixed ssl so uh meow
I guess I’m Mrs. Slocombe now, I have wild colorful hair and always talk about my pussy.
So once again I was asked to look at one of our transmitters as after it got split, reconfigured, unsplit, and put back on air, it was only making 75% power… then suddenly, 50%. Very weird. Faults showed an intermediate power amplifier not working, but why? After trying to swap it I noticed one of the power pins on this weird connector at the back had kinda fallen into the module. Here’s the connector and the back of the module.
The connector is a DB 5W5 which is modular and lets you field configure it for whatever floats your boat. In this case it’s four big high current pins and one RF connector.
After not having any luck swapping the module and noticing it seated kinda weird, I called up GatesAir support and was asked to inspect the matching connector on the backplane.
Well There’s Your Problem, they’re all BURNINATED.
Here’s the inside of the module from when I opened it to reseat the pin.
I told my director of engineering about what I found and I’m pretty sure his response was:
The parts quote was $1900 for the backplane and they still haven’t quoted me for the part on the modules. To be honest I don’t think they even like talking to me at all, even when I’m just being a proper friendly person just trying to make wattage.
Then I learned that my director of engineering just resigned. He’s going over to PBS. I’m really happy for him but trying to think of how we’re going to reorganize has me all
Anyway, an afternoon run up to the forest, a day off after spending so much time on that transmitter, and some kitty cuteness helped quell the possum hissing.
Other silliness:
Potentially useful reaction pic:
Transmitter bear, high up in the sierras:
A PissTek fan? No wait. Remember how I said I like how radio doesn’t have graphics systems? This video card’s fans both locked up and killed a big monitor wall. The video processor for this is a single point of failure (of course) and the wall is pretty much the entire news set (of course). These frameless fans are of an unobtainable size but I found that an 80mm x 10mm fan would fit here. These are also vanishingly rare but I was able to get some that Digi-Key still has…
Gingy and Scrappy love the cool, freshly pressure washed patio.
So I have melted from cute when Cassie here helped me turn a screwdriver, but now she’s also helping me with component level repair….
Warming up the Cattoscope….
Sniff snuff sniff snuff hey, what’s this? She stopped and gave me a look after sniffing right here….
Yep, that old Sprague cap has signs of creepage around its seal!
Clearly I am but part of a team of two, and the other member of the team has toes that look like beans.
I should also mention she likes turning on my GW/Instek GDM-8251A multimeter. I think she likes the feel of the power switch and the little relay plinks it makes as it powers up. She leaves it on a lot, so I have the default power up state set to come up with the display dimmed to reduce phosphor burn in. (It’s a thing with VFDs too! Look at your old VCR!)
It’s just about naptime
Today’s— uh, victim— JBL LSR2325P active studio monitor. It’s a nice sounding biamplified monitor with an active crossover system and suspicious “Imagine” brand capacitors. Hmmmmm. 😉
Our music producer came to me with this loudspeaker he uses to play his creations for our news director, among other things, because it was crackling and popping ferociously when the input gain knob was touched. I found the input gain knob loose on the rear panel and guessed I’d also find cracked solder joints. But where?
Input gain control is below the inverted plastic bathtub under that board. So how do you remove this plastic bathtub? Desolder the shitty thermoplastic power switch—- which will melt and eject its metal parts. WTF??!!
You can see the switch on the panel here – it’s a snap in flange mount – the only way to get around doing this would be to cut away the plastic flange and back it out, I guess. The tub it’s in is sealed so this wouldn’t create an air leak. But still— AARGH!!! Also, WHY THERMOPLASTIC? I have a problem with this. See, if the switch starts warming up, the plastic will soften, removing pressure from the contacts, creating more heat. Eventually the fault will only clear when the switch either totally loses contact or the thermoplastic erupts into flames.
Proper electronic assemblies use thermoSETTING resins. Glass reinforced polyesters/epoxies are nice. These are resins that set either when two parts (a resin and a hardener) are mixed, or enough heat+pressure are applied to kick over a curing reaction. This reaction is a one way process and the resulting product WILL NOT MELT and soften. It may eventually be flammable, but most thermosetting resins, especially glass fibre filled ones, have a very good track record of self extinguishing.
Phenolics are very common in solderable connectors. You can always tell when you’re dealing with a phenolic resin because it will not soften and allow the connector to deform with extended heating during soldering. These resins are often colored teal blue/green, or a tan color on Amphenol products. Ever wondered what the name “Amphenol” is about? 😉
Wikipedia article on thermosetting polymers
I don’t even want to think too hard about what that AC power inlet fixture is made of, all things considered.
The header pins leading to both the boards inside this tub were also graced with total shit-grade soldering and I reworked them. There’s one board below with the three jacks and one board above with the amplitude pad and the HF/LF trim filters. I resoldered the input pot and tightened the nut around it with some Loctite purple on it. In theory, I probably should have used blue, but I can’t find the blue, and red is right out of the question. Whatever works, right? I’ve had just as good luck with things like this using nail polish on them.
That’s the fate that befalls any nail polish I buy that looked GREAT in the store but when I put it upon my claws it turned out all watery looking or otherwise unsatisfying. (“NYC Color”, this means you. Well– some of their shades. Some of their newer ones are actually formulated with, well, color, in them.)
After this– I can’t wait for my assistant here to show up so I can run my fingers through his thermal insulation and hear him make silly happy squeaky meows.
The overnight security won’t let me leave without petting him first.
This place is bonkers….
