Radio Shack has lost it…

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What you are looking at is the prime endcap space in the middle of my local RadioShack store.

Years ago, this would have been occupied by a home theater system, high end stereo, or something that someone would have actually bought, and it would have made the salesperson who helped them with the transaction a good amount on commission.

Now, it’s stupid t-shirts.

Radio Shack is not much longer for this world. They’ve been my go to place when I need a connector or some simple part on short notice, but I don’t think they’re going to be there for me much longer.

They’re the last venture of the Tandy Corporation, which renamed itself to Radio Shack. Tandy Corporation has engaged in many potentially successful ventures over the years, yet methodically run every single one of them into the ground in flames. Some that come to mind, of course, were Incredible Universe, the Tandy Computer brand, TechAmerica, and Computer City.

I used to love Radio Shack in the late 80s through mid to late 90s. They used to have a lot of components and supplies for my tinkering, and it was with the assistance of a Technician class study guide that I purchased at a Radio Shack in 1999 that I got my ham radio license. Back then they still even carried some ham radio equipment in their stores. I remember they still had the HTX-202/404 brick handhelds in their stores, and a 2 meter mobile radio, along with some Vectronics stuff (was this before or after they were part of MFJ Enterprises?). TechAmerica, a mail order only venture (as far as I know) had even more ham gear available when they were around.

What they didn’t have in their stores, they had available in a 200+ page catalog, available for shipment straight to you or to your local store.

In the late 1990s they started to lose focus on what their core business should be. They began to heavily push cell phones, then gradually cut more and more into their retail planograms* to devote more space to cell phones. Eventually, half the store was occupied by cell phones and accessories. Components were pushed back into organizer drawers in one back aisle. They stopped carrying home theater and stereo gear entirely as of about 2010, instead just focusing on low ticket items and cell phones. The commission based sales model would have seriously stopped working for their employees at this point in time, as there’s no longer such a thing as making a $50 commission on the sale of a $500 TV, for instance…

Now, today, I walked into one of their stores and this was in the middle. The cell phone display was pushed against a wall – there’s a good chance they haven’t sold a phone in quite a while, especially since their prices (up front or hidden!) are not competitive with other retail outlets or buying directly from the carriers.

At some point they did make an effort to reconnect with the electronic hobbyist and education markets, but it was all too little, too late. A line of kits they worked on in conjunction with Make Magazine got liquidated en masse at clearance prices…. then promptly reordered. They also carry a number of Seeed Studio kits and boards, but haven’t made any effort to promote this; they are merely just… there.

Despite the large uptick in interest in ham radio, they have not re-entered this market. They don’t even sell TV antennas for those who want to hook up their television sets for over the air programming.

This of course leaves a space for other businesses to fill. Systemax/TigerDirect is now starting to carry electronic kits in their stores. Who knows, maybe you’ll be able to get an oscilloscope there too, just like you can at a Fry’s. Alfa Electronics has been doing great business at their two store locations, and one of my fellow broadcast nerds has started doing some electronic parts sales from his business, Smiling Dog Systems.

It’s just a shame about Radio Shack. The mighty have truly fallen.

The Night of the Smoking Dummy Load.

A couple of months ago, I had a silly adventure. I was at the Homestead tower, just a couple blocks down the street from a Miami-Dade Fire Rescue station that was, at that time, on “brownout” due to Miami-Dade County budget issues. If you want to learn more about how Miami-Dade’s budget and politics work, I recommend you go check out Eye On Miami — I distance myself from politics to make life more pleasant.

The first thing I’m greeted by is a blaring fire alarm in the hallway of the transmitter building and a really foul electrical fire smell, but no particularly visible smoke. I figured either it wasn’t a particularly big one or it had already gone out and the smoke had been evacuated by an exhaust fan. Either way, I proceeded carefully inside and found the alarm belonged to one room on the first floor with the transmitters for Minnesota Public Radio’s classical station. I called their central control as indicated on the door while using an Xcelite “greenie” as a Sonic Screwdriver to gain access.

Harris HT 25 FM - Well it WAS black once.
Harris HT 25 FM – Well it WAS black once.

Inside I found everything coated in some kind of white sticky filth. The air filter on the Harris HT 25 FM transmitter’s power supply was totally caked in it and I’d first assumed this may have been the source, as the power supply was subsequently running too hot to touch. Keep in mind this is a power supply unit the size of a Volkswagen Type 1 “bug”.

At this point he had an engineer on the way to look at it but our conversation turned to what on earth had Let The Smoke Out. See, there’s a theory with electronics, they all work because they have this Magic Smoke sealed inside at the factory.

OLYMPUS DIGITAL CAMERA

Once you let the smoke out, the device never functions again, and it is impossible to force it back in there. Now I wish I’d scraped some of that white gookus off, maybe someday science can figure out how to coalesce it back into injectable Magic Smoke essence. Aaaanyway…..

The person at MPR indicated that he’d had contractor after contractor working on the site, whose maintenance is principally contracted out to Clear Channel Miami. His only indication that there might have been any trouble was that he tried to run a backup transmitter at the site and “it just wasn’t coming up right”. I proceeded to clean their filters while I waited for someone to arrive. OLYMPUS DIGITAL CAMERA

Shortly afterwards I found some very melty things in the vicinity of the dummy load. The site has two transmitters, one antenna, and one dummy load. A coax switch in a DPDT (double pole / double throw) configuration routes the output of both transmitters so that if one is set to antenna, the other is set to dummy load. This way one of them can be run for testing/maintenance while the other is on air, seamlessly. Smokelessly, even, if everything works right…. which it didn’t really.

OLYMPUS DIGITAL CAMERAThe object seen here is the top of the dummy load. Down inside the gray box, there is a star shaped holder clamped to the tops of six noninductive “Globar” type resistors that go down a chimney with a blower at the bottom. RF is applied to the top and grounded at the bottom, and they’re paralleled to form a load that presents 50 ohms impedance at  up to 25,000 watts…. IF THE AIR IS FLOWING. Unfortunately, there was a little oopsie. Note the heat darkening to the metal grille, the white gook splattered on the two pieces of spare feedline to the left…

OLYMPUS DIGITAL CAMERA…And this Krispy Kable…

The air coming out of the load by convection was probably over 500 degrees F. It seems like the resistors got just hot enough to smoke off the coating on the outside but not actually burn out or crack – the load actually tested 50 ohms at DC after the incident.

In the above picture you can see a Bird wattmeter line section. The “slug” which contains the coupling circuitry to pass a reading down the cable as a DC current is not in it. Here is what happened to the slugs from the heat.OLYMPUS DIGITAL CAMERA I call these flame broiled Birds.

The plastic top on one actually became convex and pushed the label off; on the other, the plastic bottom that protects the sampling element warped and tried to fall down the line section when I removed the slug. It’s actually fascinating to see how these work inside, they’re sort of a non-contact coupling with an L/C circuit and a diode. One of these days I’ll have to learn the magical theory as to how these directional couplers work. (Yes, they’re directional – they measure the power flowing in the direction the arrow is pointed, and you can turn them around to switch between measuring forward and reflected power!)

The backup transmitter was a Rockwell-Collins that looked distinctly older than I am. The other guy who showed up on site (whose name I have sadly forgotten) went to turn it on. He pressed filament on… and the dummy load’s blower began running with no problem. Mystery upon mystery, what happened? OLYMPUS DIGITAL CAMERAAt this point we waited for a “ready” indication telling us it was time to turn on the high plate voltage to make it start.

 

The old beast had none.

 

I was actually wondering if it’d light the Plate Off button or something as a ready indication, but it didn’t do that either. I started messing with the multimeter function on the front panel and observed that the meter didn’t work right, and the exciter’s power seemed to have flicked on and off a time or two. OLYMPUS DIGITAL CAMERA

With us both standing in front of the transmitter, he reached for the PLATE ON button.

Old tube broadcast transmitters like this usually run 4000-9000 volts DC on the plate at several amps. When voltage like that finds an unwarranted path, the whole unit tends to respond with an unwelcome BANG. Knowing this, I just about dashed from the room before he could touch the button.

It made two wimpy clacks, but nothing happened. The plate voltage kind of wobbled around but the wattage never went anywhere. The multimeter (when I could get it to work) indicated that the bias voltages were there, but it looked like one supply voltage was missing in action.

He asked me if I had any ideas. I looked at his feet and saw that he was wearing sandals. I was wearing steel toe boots. I said, “Hold on, I’ve got this” and kicked the unit in the front panel. The sound from the transmitter gained a bassier thrumming note, and a glance at the 1897867_10202606324673089_224100874_nmeters showed 25,000 watts output.

To repair something like this, you must truly understand it.

Last I heard they were going to go back in there and reverse-engineer the mess that was made of the control wiring to allow this transmitter to run without the load blower running and its airflow vane switch moving. Alas, the only way I will ever know for sure is the smoke test: Did the building fill with smoke again?

I’m also hoping that Harris HT 25 FM gets a very good internal cleaning at some point. They are known for making some spectacular bangs when they get unhappy.

Tascam CD-500B Button Repair

The Tascam CD-500B is one of a sadly quickly dying breed — a professional grade CD player, with balanced audio output (and AES/EBU digital) as well as RS-232 and contact closure remote control. Unfortunately, it features some very non-professional grade buttons on the front panel. I don’t even understand what on earth they were thinking.

Symptom: Buttons “fall” into front panel. Operation of button is impossible.

Broken off button
Button with broken hinge. Note that the switch is off center and sort of BESIDE the button, not directly under it as it is on Denon players

Problem: Thin plastic hinge section of button has broken.

Solution: Wedge button in place from below so it’s trapped between the front panel, the wedge, and the switch on the circuit board.

Disassembly of the player: This player is truly and sadly built like total BPC (Black Plastic Crap). You have to remove the rack ears, top cover, and the entire front panel. Carefully release the wires going to the front panel and unscrew the one visible grounding jumper. Unplug the two multi pin connectors (they cannot be mixed up – different number of pins). Remove all the silver screws around the front of the player and release the tabs on the right and left sides, then drop the front forward. Remove two screws holding in the LCD, then you can unscrew and remove either button board as needed.

Wedge the broken button(s) from below, then set them into the front panel with it tilted downwards and reassemble.

It is worth noting this player uses what appears to be a standard slotload SATA cd-rom drive as its transport! I have not tried substituting drives yet to see what happens. The buttons break before the transport 🙂

When you and your Arduino do not give a fuck

I can say fuck on the Internet, right?

the wiring is


// fucks.ino: Arduino sketch for automatically running out of fucks to give. Should work on any board, wired to an HD44780 based display or compatible. Does it look like I give a fuck?
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
// rs, enable, d4, d5, d6, d7
// on the lcd end these match to:
// 4, 6, 11, 12, 13, 14
// don't forget the 10k pot between gnd/5v with the wiper on lcd pin 3, ground pin 1, and +5 on pin 2,
// or a completely negative number of fucks will be given. this is undesirable but hilarious.
int fucks;
void setup()
{
fucks=100; // or whatever. watch me give a fuck.
lcd.begin(20,2);
lcd.setCursor(0,0);
lcd.print("Fucks To Give:");
lcd.setCursor(0,1);
lcd.print(fucks);

}

void loop() {
if (fucks>=1) {
lcd.setCursor(0,1);
lcd.print(fucks);
delay(250);
fucks--;
}
if (fucks=0) {
lcd.setCursor(0,0);
lcd.print(" Out Of Fucks ");
lcd.setCursor(0,1);
lcd.print("To Give! Fuck Off.");
delay(30000); // or just go fuck yourself
}
}

I could put up an example picture and video but I am out of fucks to give

Cleaning your MAF sensor for performance and profit

2012-12-30 19.46.01The MAF sensor is a device that measures the amount of air flowing into your car’s engine air intake and is used to determine the appropriate amount of fuel to shoot in to achieve an optimal fuel/air ratio. Incorrect MAF sensor readings, caused by contamination, can lead to loss of performance, fuel economy, or rough running. That being said, let’s begin! This will take only a few minutes and will most likely save you money on fuel when it’s done.

First, obtain a can of MAF sensor cleaner. Your local auto parts store should have it, and a can is probably good for 5-6 cleanings. Clean it whenever you clean/replace the air filter.

On some vehicles you will have access to the MAF sensor immediately upon opening the air filter housing. On others there will be stuff in the way and you’ll need to remove it from the intake line. It’s usually held in with two screws.

Mazda 6 (2.5 L4) MAF sensor. It's located just beyond the air filter box.
Mazda 6 (2.5 L4) MAF sensor. It’s located just beyond the air filter box.

Step one: Remove the screws holding in the sensor and pull it out CAREFULLY – do not touch or damage any of its parts. Some sensors may have a fine platinum wire that must not be damaged or… well, you’re stuck buying a replacement for something that has a platinum wire in it. Gross. 😀

The pictures shown here are on a Mazda 6 with a 2.5 liter L4 engine; however, I’ve seen the exact same MAF sensor setup on many other import and domestic vehicles including Toyota, Nissan, and *some* Honda vehicles (they only recently started adding MAFs — many Hondas simply do not have one and rely instead on manifold pressure + throttle position to determine the flow rate).

Step two: Spray it down!

The spray can may come with a straw – you can attach that to the nozzle and use that, but do not stick the spray straw into any part of the sensor. Do not touch any small wires on the sensor or expensive problems will result. This sensor appears to simply have none. I’m not totally sure how it works, but the fact is, it doesn’t work well if it’s grungy. 🙂

The cleaner works very quickly but I usually try to spray it, let it stay soaked for a minute, then spray it down again to rinse. Repeat if you still see any visible contamination.

Rub a dub dub, baby.
Rub a dub dub, baby.

Step three: Reinstall the sensor and you’re done!

Now start up the car and drive off, you may notice an improvement immediately. If you don’t, you probably will the next time you fuel up.

A random tip: Track your gas mileage at http://www.fuelly.com and compare it to that reported by others to make sure your vehicle’s running well.

The Water Cooled IC-V8000

I’ve always had a soft spot for the way Icom designs their mobile ham rigs. See, someone at Icom realized that hams are ridiculously longwinded and will overheat many commercial grade radios made for the typical 5/5/90 duty cycle (5% TX, 5% RX, 90% standby) easily… so they designed most of their radios with giant passive heatsinks integral with the exterior chassis of the radio. On some of their radios there is a small cooling fan at the back that pushes a little more airflow over the chassis if needed. I used to have an old IC-229H which just had a huge passive heatsink at the back, and there’s an IC-2100H in my parents’ car that just does the whole case/heatsink thing for cooling.

Unfortunately someone, in the process of building an Echolink node around an IC-V8000, thought they needed a bit more cooling and then this happened…

 I don’t entirely understand WHY this was done — the radio has a very large heatsink of its own… or HAD a very large heatsink of its own, as it may be. It’s a 75W radio and could easily be turned down to mid or low power to further reduce heating problems without doing… that.
The images were found on Facebook and I’m presenting them anonymously to protect the guilty party XD
Shown below is an unmolested reference model:

User interface design FAIL? In MY automobile?

It’s more likely than you think!!

 

The next time you turn on your car, leave the key in the “RUN” position without turning it all the way to start and look at the lights that will appear on the dashboard. You should notice somewhere a small battery icon.

And there, folks, is the fail, for despite being a glowing battery icon, this light does not indicate a problem with the vehicle’s BATTERY.

I’m not going to put up schematics and stuff because that’s just getting too technical* for this. In short, the battery light indicates a problem with your vehicle’s ALTERNATOR.

The ALTERNATOR light, which inexplicably has a freaking BATTERY painted on it, indicates that the vehicle’s alternator is not charging the battery when it SHOULD BE. It came on when you turned the ignition on without starting the engine because the alternator is not being spun by the engine. Once the engine is running it should go out, because the alternator is being spun and is generating electric current to recharge the battery.

You may see the light occasionally flicker under any situation that keeps the alternator from spinning. Driving through a puddle may wet the belt and cause it to slip, causing the light to flicker. Forcing the engine RPM too low on a vehicle with a manual transmission will also make it flicker. In either case it will go out once the alternator spins back up to operating speed.

If the alternator fails to generate power, due to a broken/failed belt (you may also notice a loss of power steering assist and air conditioning!), the light will come on. The car will stop running once the battery runs out of power.

If the alternator itself fails, it may also turn on the battery light. Note that the battery light signal is generated by the alternator, so a particularly rotten failure of the alternator’s internal electronics may not necessarily turn on the light. My father had the electronic voltage regulation controls inside the alternator on a Volvo 740  fail like this while driving on the Florida’s Turnpike in the middle of nowhere – the first sign of trouble was when the antilock brake controller (dimly) illuminated its fault light due to the low input voltage!

Soooo… why not label the light “ALTERNATOR”? Even the execrably designed NABI 40LFW transit bus has the light labelled as “GEN STOP”. Suggesting that it means the GENerator has STOPped working is infinitely more useful.

* me, resisting the urge to geek out about how this actually works? INSANE

Miami and Tampa Frequency Lists for the Wouxun KG-UVD1P

Hey, it’s me, I want to give you some good frequencies…

Miami Area Repeater Listing

Tampa Area Repeater Listing

Use KG-UV Commander to edit and transfer the files to the radio.

Under the hood: Morningstar SunSaver MPPT.

Buckin' Bronco

This is the Morningstar Sunsaver MPPT charge controller, capable of pumping 15 amps into a 12 or 24 volt battery system from an up to 75V input. It’s fairly simple, though the 6P6C jack can be used for Morningstar’s Modbus system or Remote Meter to add more control, programming, and monitoring capabilities. The unit is driven by a Microchip PIC18???* microcontroller.

A typical MPPT controller consists of a switching buck or buck-boost converter with the input connected to the solar panel array, and the output connected to the battery system. A microcontroller monitors the solar array voltage and current (and multiplies them to calculate the power) periodically, and adjusts the switching of the converter appropriately to keep the input side voltage at the solar array’s maximum power point, Vmp.

Inside the Morningstar Sunsaver MPPT, there is… a switching buck converter with a micro… etc. Here you go:

* The conformal coating stuck to the top of the chip made it difficult to read. Like the flavor of PIC matters? XD

Control/Logic Board

No fans or other active cooling are needed. The inductor is thermally coupled to the back of the housing, which is a tall metal fin attached to the heatsink/base. The switching transistors are, undoubtedly, potted somewhere in there. The potted construction is also used on the SunSaver PWM controllers.

Simple, elegant, but here’s the big question: WHY does it cost $250?! Rest assured, I’m scouring the market for some *good* low cost MPPT controllers. This is just a very good and not quite as low cost controller!