The Smell of Molten Projects in the Morning

Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.

Author: Ed

Credit Card Services: Payback
If you have a landline telephone number, you’ve probably been robo-called by “Rachael” from “Credit Card Services” with an offer to lower your credit card rates. She gives you two options:
- Press 1 to speak with a live operator
- Press 3 (or, sometimes, 2) to prevent further calls
I presume you’ve discovered that pressing 3 has no effect.

Credit Card Services is obviously a scam:
- We’re on the FTC Do-Not-Call Registry
- We don’t have a pre-existing business relationship with CCS
- They use a robo-dialer
- Pressing 3 (or whatever) doesn’t discontinue the calls
- Their caller ID is spoofed
Rather than get mad, play along. CCS obviously preys on suckers willing to read off their credit card information to total strangers, so you can retaliate by stringing them along as far as possible, thus increasing their cost-per-sucker. Admittedly, their “agents” are (at best) minimum-wage slaves, which means you’re messing with their income stream, but after the first few months it becomes pretty obvious that the calls will never stop and you may as well roll with the punch.

Suggested topics, all presented in a slow monotone with long pauses:
- Making sure they’re not associated with any of your credit cards (they aren’t)
- Understanding whether they’re offering a loan to pay off your cards (they lie)
- Asking for a callback number in case the call gets dropped (it’ll be a junk number)
They expect a minimum $4k account balance with the usual usurious credit card rates. Getting them to admit any of that requires carefully paced inquiry, because their script requires getting my balance before they devote any more time to me. I haven’t fed them any (totally bogus) numbers yet, but that may be the only way to get beyond the preliminaries.

Topics I’ll investigate in upcoming calls:
- Their current interest rate
- The repayment schedule
- What they hold as collateral
- How’s the weather where they are (it’ll be terrible here, for sure)
Thus far, I’ve discovered that any mention of these topics produces an instant disconnect:
- Why pressing 3 does not discontinue further calls
- Inquiring about their company mailing address
- Asking to speak with a supervisor
- Whether lying to strangers all day affects their personal relationships
My record so far is 3:05 from picking up the phone, which includes the recorded message and a bit of hold music.
2011-12-16
Roof Shingle Fungus Redux

Cleaned the gutters a while ago and the shingle fungus is getting worse: more sites and more stains. I sprized some general-purpose fungicide on the area over the kitchen:

Shingle fungus – east slope

And down the valley between the north and east slopes:

Shingle fungus – north and east slopes

We’ll see what happens by next spring; I hope the larger moss clumps will take the hint.

However, that short length of copper wire seems to be improving things. Here’s the before:

Copper effect on roof discoloration

Compared with the current state, from a different spot:

Shingle fungus – below Cu wire

The intense streaks have vanished, leaving a uniform lighter gray layer, and the upper area near the wire looks, mmm, less awful than the lower areas. I think running copper wire or zinc strips (which I have not found at the big box stores) along the ridge vent will do wonders, although I’m not sure how to anchor either one along the hip joints between the other slopes.

2011-12-15
Weller EC1201A Soldering Handle Failure
For the last few days, my trust Weller EC1000 soldering iron (well, station) has been misbehaving: shortly after cleaning the tip, it would become covered in charred residue and slag. Today, the LED I’d hacked across the heater terminals inside the base stayed dark, even though the tip was hot, and then became sensitive to the handle position. Obviously there’s a loose wire inside, right?

So I took the handle apart by removing the two screws on the front plate:

Weller EC1201A soldering handle innards

The trick to getting the guts out is to push down on the tab inside the handle that locks the cord strain relief block into the handle. After that, everything comes apart with very little force at all.

Contrary to what I thought, the heater is in the tube surrounding the temperature sensor probe. Looking at the connector on the front of the base unit, the key is on the left side and the wires going clockwise from above the key are:
- Yellow: heater
- White: heater
- Black: sensor
- Red: sensor
- Green: shield
I would have sworn the red & black were the heater, as they have special-looking brass/bronze/copper colored pins & sockets. Wrong again.

The temperature probe comes apart thusly:

Weller EC1201A temperature probe disassembly

Basically, slide the connector and ceramic-coated sensor out of the back of the black shell, then pull the spring-loaded sheath out the front.

I hoped for a laying-on-of-hands fix, but it was not to be: the tip heats while the LED (which I wired there early in the iron’s life) across the heater power remains off. But the LED blinked on intermittently with slight pressure on the iron’s tip; a bit more poking and prodding isolated an intermittent open-circuit to the ground wire just outboard of the strain relief at the handle:

Soldering iron cable failure

A bit more poking & tugging isolated an intermittent high-resistance short (a few hundred ohms, more or less) to a section of cable half a foot from the base connector at the bottom of the cable’s natural loop when the iron’s in the holder.

Unfortunately, fixing all that didn’t restore the iron to life. It seems that the temperature sensor (a thermocouple?) has failed, allowing the tip to heat well beyond any rational temperature. Now that I’m looking, a cleaned solder layer turns blue with oxidation in a matter of seconds and rosin chars instantly. The temperature control knob has no effect whatsoever.

The date codes inside the box show it’s been with me since late 1982, so on a dollars-per-year basis the thing has been a bargain. A new sensor is $60, a new handle is twice that, and I think it’s time for a new iron… at less than the price of the sensor alone, I think that’s OK.
2011-12-14
RCA Alarm Clock Dimming

Mary prefers dim digits on the bedroom alarm clock, far below what the usual DIM switch setting provides. I’d slipped a two-stop neutral density filter in front of our old clock’s VFD tube, but the new one has nice green LED digits that ought to have a tweakable current-setting resistor behind the switch. Indeed, a bit of surgery revealed the switch & resistors:

RCA clock – DIM switch and resistors

It turns out that the 220 Ω resistors set the DIM current, with the 100 Ω resistors in parallel to set the BRIGHT current. Weirdly, the display operates in two halves: one resistor for the lower and middle segments, the other for the top segments. The resistor numbers give a hint of what the schematic might look like:

RCA clock – LED current-set resistors

The current control isn’t all that good, because the brightness varies with the number of active segments. With 470 Ω resistors (yes, from that assortment) in place, the variation became much more obvious; the LEDs are operating far down on their exponential I-vs-V curve. We defined the result to be Good Enough for the purpose.

Four short screws hold the circuit board in place, but one of them arrived loosely held in a pre-stripped hole. I cut eight lengths of black Skirt filament, anointed them with solvent adhesive, dropped two apiece into each screw hole, and ran the screws back in place. I likely won’t be back in there, so it should be a lifetime fix:

RCA clock – ABS filament in screw hole

Done!

As with all the trade names you remember from back in the Old Days, the present incarnation of “RCA” has nothing whatosever to do with the original Radio Corporation of America:

RCA clock – data plate

2011-12-13
Christmas Cactus Time Lapse: Drat!

With macro lens adapter in hand, I started taking a picture a day with the intent of making a time-lapse movie:

Christmas Cactus flower bud

Of course, that particular flower bud fell off after three days.

We returned the plant to a cool location for the Christmas season. Evidently the kitchen was far too warm for best performance…

2011-12-12
Brita Pitcher Lid Hinge

This pitiful excuse for a hinge actually lasted far longer than I expected:

Brita pitcher lid hinge pins

Also much to my surprise, the plastic solvent-bonded to itself, although I doubt either of those pins will survive another four years.

The yellow discoloration seems to be most prominent on the inside of the lid, which suggests the water is nastier than they’d have you believe. The disinfection additive has switched from chlorine to chloramine and back to chlorine over the last few years, which may have something to do with it.

2011-12-11
Mindless Entertainment

Sometimes I need a task that doesn’t require a lot of thinking, like reducing the entropy of a bag of mixed SMD resistors…

Sorting SMD Resistors

I’ve heard tell of a TV-thing that serves the same purpose. Dunno when you’d have time to sort your resistors, though.

Resistors being marked, I didn’t need those SMD tweezers.

(Yes, this makes no sense. It’s mindless. Sometimes, ya just gotta do this stuff. OK?)

2011-12-10