Following up on yesterday’s post, this photo of a sign posted downtown pretty well describes how Seattleites react at the first sign of flakes falling from the sky.
This photo courtesy of my friend Jamie Swedler.
I’m taking a short break from writing about technical projects to share some of the recent interesting weather we’ve had lately. It snows about once a year in Seattle, and every year we’re taken out of commission for a day or two or three in this case. Most times it’s only an inch or less of snow but this time we ended up with closer to 6″ over the span of a couple days followed up by freezing rain and the accompanying downed trees, blocked roads and power loss.
Metro buses started running on chains on Monday in anticipation of a storm that didn’t really arrive until Wednesday, since we saw a tiny dusting over the weekend. This is always interesting and results in a lot of broken chains littering the roads after the snow melts. I’ve been on a bus while a chain came off and it sounds like the bus is about to rip in half, I’d hate to think of what would happen to the next car back’s bumper.
Metro bus chains (Seattle PI)
It’s always interesting when Seattle drivers try to get out in the snow. For the most part, nobody has any idea how to drive in it. People don’t use chains, or don’t know how to put chains on properly. Or just go too fast, too steep, and crash and slide into everything like this video taken from someone’s apartment on Capitol Hill. I prefer to stay inside or take the bus.
Some interesting things do happen, though. It’s always entertaining to watch buses be towed by an enormous tow truck like in this video from the Seattle Transit Blog (where they offer a convincing defense of the city’s sometimes confusing snow response) and this one is no exception with the flying electrical sparks.
I went out to investigate and took some low-quality photos of the block around my neighborhood.
In the first set of photos there was about 1″ on the ground; it accumulated throughout the day and the next to be about 6″ total. And that’s probably the one snow storm we’ll have this year, if past are any indication.
All in all it wasn’t too bad, but we did have a bit of alarmist reporting on Tuesday. Pretty much every media outlet including the highway information signs warned of a winter storm on Tuesday, but it arrived a day late. Nearly 90% of my co-worker went home early; across the region that’s a lot of lost productivity and lost wages for people. On the other hand, being stuck out in treacherous conditions in an area chronically unprepared for snow has a definite cost in terms of accidents, delays, and travel disruptions. I wonder what the total economic impact of a bad forecast is, and whether a conservative forecast predicting snow when none arrives has a smaller or greater cost than an optimistic forecast that leaves people stranded.
I was talking with a fellow antique radio hobbyist on the phone the other day about a repair he was working on. A TrueTone battery radio, he’d taken care of all the important steps – checking out the tubes, replacing capacitors, replacing the broken wires, that sort of thing. The radio worked before the service but wouldn’t play after and so we talked through the steps to see if there was anything he’d missed and get a second set of eyes on it.
This set had a lot of rubber covered wire which has degraded over time and turned into bare wire, so some of that needed to be replaced. This started to become a problem around the second half of the 1930s up through WW2 and sometimes after…you can replace the wire or unhook one end and cover it with heat shrink tubing. Everything sounded good until I heard about replacing some wires “on top of the variable capacitor.”
RF issues in these old things are insidious and tough to locate and it takes a lot less than you’d think to throw it off. Wire diameter, wire length, physical positioning and shielding are all involved to some degree. Wiring changes in the front end are the first thing to take a look at. He’d mentioned a broken wire on top that he’d replaced.
That rang a bell. My next question was, “Were they twisted around each other?” They had been. Problem identified.
This twisted-wire “fake” capacitor is called a gimmick and was a way to save a few cents on the manufacturing cost. It doesn’t take much to make a capacitor. All you need is a two conductive charged plates separated by something non-conductive; two wires twisted around each other don’t provide much but but can make a few pF. Just enough to couple a small bit of a high-frequency signal like in the RF or IF frequencies. It’s not always obvious that a bit of twisted broken wire is actually a circuit feature, though – especially if it’s in bad shape from age, so replacing it with a new piece of wire is a pretty obvious thing to do.
Unfortunately in this case, though, the circuit as connected is shorting the oscillator and antenna sections of the variable capacitor together and the radio won’t receive anything. It was a really quick fix, though. Just twist a little tighter and snip!
Doesn’t look like much but it gets the job done – the radio fired right up and received stations after the quick change.
He sent over some construction photos to show how you can make your own gimmick replacement:
Thanks Steve for the photos! I’m glad the TrueTone is back in operation.
I’m always happy to throw out some advice about antique radios and radio repair, so if anyone reading has any questions feel free to drop me a line through my About Me page, or make a comment reply and I’ll get back to you. Feel free to share photos and stories as well, I’ll post the most interesting ones on here so everyone can benefit.
It’s the winter here in Seattle and it gets cold outside occasionally. Cold enough that I can’t vent my soldering fumes out an open window like I normally do most of the year, but I don’t want them in my apartment. Fortunately for me, my chassis stand is the same width as my stovetop and sits neatly under my externally-venting range hood so I can move it over there for ventilation.
The stand can hold the chassis up at any angle and supports a lot of weight. Every time I use it, I’m impressed with the build quality and flexibility. It’s not as nice working in the kitchen as it is on my normal workbench, but it gets the job done.
It’s 1987 and I’ve been needing a new laptop. After a careful process of comparison shopping I settled on my Sharp PC-4501 from Montgomery Ward. Let’s open it up and take a look!
For only $699.99, it’s a state of the art machine. A 7.16MHz processor, 640KB of RAM, and mine comes with an optional second 3.5″ floppy disk drive! Now I can work on a program and save its data at the same time. It was designed to be especially easy to use.
Good thing they provide unpacking instructions inside the box.
It comes with an instruction manual and the operating system disk.
I’ll make sure to return the warranty card.
Power up…time to go through the BIOS setup!
One thing I don’t like so much is the screen is front-lit with ambient lighting, and is glossy. Makes it a challenge to see what’s being displayed sometimes.
We’ll try out a productivity application.
Looks productive!
I can’t wait to begin editing documents and spreadsheets from my own home. It’ll be so much easier than my old typewriter!
I was cruising eBay randomly the other day and made an incredibly lucky find…a 1934 Simplex Model P Dual Band tombstone radio had just been listed. I have a pretty low maximum that I’m willing to pay for any radio, as I only buy fixer-uppers and not completed radios, so don’t buy them all that often but this one jumped out at me.
It’s dirty, as can be clearly seen in the photos. It could use some attention on the trim, but the finish is in pretty decent shape; there are some veneer issues on the bottom as well that will be a new skill to learn about fixing for me. And the knobs are wrong. Electrically, it’s your standard 1930s “Parallel AA5″ design: 6A7 6D6 75 42 80. But, it has a lot of potential once it’s cleaned up and fixed up and will display very nicely.
This one makes the cut on the display shelf, so I’ll be fixing it up sooner than later.
A client came to me with another Grunow 589 needing repair. I’ve seen this model radio before in my shop and it was pretty exciting to work on another identical one. This particular one came in excellent shape – it looks like it was stored well for most of its life. The chassis arrived with no dust, no rust, a shiny coating, and not even any cadmium flaking off under the chassis.
The radio looks like it was well loved during its time. Built in 1937, it has evidence of being repaired several times all the way up through the 1950s. The UL Reexamination Service sticker is somewhat of a testament to this as well, and the fact that it’s in nearly perfect shape.
I performed the customary intake checks – all coils, transformers, tubes and controls. This one was in pretty good electrical shape. Only two of the tubes needed to be replaced after the years, testing very weak. The volume control was in bad shape, though – same as on the other 589. Unfortunately though for this particular radio, it couldn’t be saved and needed to be replaced. The output transformer connecting the radio to the speaker was also open and needed to be replaced before the radio would run again.
I sourced a volume control identical to the original (250K with a tap for tone compensation) and a functional replacement output transformer. With these parts on hand, it was a simple matter of performing the replacements. All capacitors were replaced with brand new models, and any resistors that had drifted in value by more than 10% were also replaced. On this radio, the first audio output tube (type 76) used a bias battery to establish a control voltage. As circuitry evolved, engineers discovered this was no longer necessary; I updated the circuit design to eliminate the battery by changing the 500K grid resistor to a 10 Meg grid resistor and jumping across the battery.
I also installed interference-suppression capacitors on the incoming power line, and a 0.75A inline fuse under the chassis to protect against a tube shorting and taking out the power transformer. With these modernizations, the radio will play beautiful and should perform without maintenance for many years.
A few parts were replaced during this operation:
The radio’s owner sent me a photo of it installed back in its cabinet after he received it from service. It looks – and sounds – great!
I provide affordable antique radio repair services in the Seattle Metro area and beyond if you’re willing to ship the guts. Check out my portfolio and information page for more details!
Antique Electronics Supply, one of my go-to vendors for supplies for working on antique radios, is in a festive mood this season.
That’s a chocolate vacuum tube along with my order of various dial lamps and a handful of replacement tubes. Very neat!
My Hakko clogged, and the cleaning pick just wasn’t working. It was time for the teardown.
I’m not entirely sure how that shape formed, but it broke off in a clean piece; the remaining tiny plug melted away after the iron heated up. That’s annoying, though.
In “House”, Season 8 Episode 5 (aired 11/7), we can see that the good Doctor has a 1937 Philco 37-620 Radiobar in his office. Unclear whether or not it has the original glassware. I’d love to have one of these in my collection, but they’re quite rare and expensive.
Philcoradio.com has some more about the history:
This Philco Radiobar sold for $252.50 in 1937 dollars, around $3800 in today’s money. This was a high end luxury for the wealthy to have in their homes, but out of reach of most consumers of the time.
