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
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. 😉
A while back I found this in service up Linguini Mountain and removed it in a session of lobbing crap into a pile in the corner. I decided to take a picture of it before shitcanning it in the e-waste box….
The open frame relay was screwed to a hole in the side of a rack, facing outwards as I recall.
What a shame. Potter & Brumfield used to make good relays too, before they just became a Tyco Electronics contract manufactured line of dumpshit. This one, alas– its service to us is done…. Whatever service that may have been.
Incidentally, trying to claim the gym at Whiskeytown for any team other than Instinct is a foolish act, for I will take it back every time I’m out there. Bwahahaha. Isn’t that right, little Mudkip of the lake?
I just received two new 4CX250B / 7203 tubes for one of our transmitters, an old Continental Electronics with the tube intermediate power amplifier (IPA).
I’m already wondering just how they’re going to fail. Not IF they’re going to fail, more like, how, and how much collateral damage will occur.
The sad story: These tubes used to be produced by Eimac and were perfectly fine. At some point, Eimac got sucked into some giant ugly conglomerate that consolidated their tube manufacturing and made some awful changes, then hacked and slashed at their product line. That effectively led to a quality fade then discontinuation of the tubes.
I’ve been pretty much informed that the way to get GOOD 4CX250B tubes is to either go back to 1981 and stockpile them, or find someone who has them sitting around from back then and hope that they’re not gassy or badly manufactured tubes from Eimac’s Salt Lake City facility.
So now, what do you get when you try to buy a 4CX250B?
….this. this is the dumpshit you get. alibaba.com’s finest, I’m sure.
These are “National Electronics” marketed by Richardson Electronics. Richardson’s website only mentions the Eimac tubes that they were a dealer for, and when these were ordered, there was a week’s delay in getting them shipped. National Electronics used to be a perfectly legitimate tube dealer or manufacturer – I think they went with contract manufacturing back in the day, as you’d see a really wide variety of their tubes out there, everywhere from receiving valves to power tubes and even indicators like Nixie tubes. Now, my best guess is it’s just a shell being kicked around via brand name necrophilia.
I don’t know if these even work at all, and won’t until I can get to a mile-high transmitter site whose means of access are currently buried in snow and ice.
So, for now, let me compare them to a new old stock Eimac tube. This is a 3CX800A7, a different tube entirely, but using the same sort of package and plate structure.
Immediately the bright silver plate finish becomes apparent, along with a far different cooling structure. The fins are brazed or soldered to the plate. This is important as the outside of the plate cooler is usually used as the electrical connection via a clamp around the tube. You do not want a bad connection in there.
And now, the Richardson/Alibaba Special – they just… lovingly shoved it down in there with a press and called it a day.
No signs of soldering or brazing are visible.
All in all, it looks like it was just smashed together using the same tooling one would use to make cheap and nasty refrigerator coils.
Now, about that gray mystery metal….
I looked at the socket pins and saw no marks on them at all, just a uniform gray coating of… whatever.
On the Eimac? There are marks in the silver plating from where the tube was put in a socket for factory testing.
Did they even——??? Is there any factory testing??
How’d this Oddish get in my transmitter?
So yeah— I’m NOT convinced these are even going to work, but I guess that’s what I can get now. Thanks, Crapitalism!