A little something to keep the mice from eating Veronica’s wires.
Well, I finally got back to working on Veronica, but this project is less Steve Wozniak and more Martha Stewart. You see, Veronica is starting to grow, and she no longer fits in the drawer where I keep works-in-progress. Before I build too many more modules, she needs a proper enclosure. I thought a long time about this, and I decided that since she’s a retro-tribute computer, she needs a retro-tribute case. I had the idea to gut and repurpose an old Philco radio. There are a zillion models to choose from (in every shape and size), they are attractively retro, and they are cheap on eBay (unless you want one of the special ones). I was pretty proud of this idea, until I later found out that using old Philcos for project enclosures is pretty common. Oh well. My mom still thinks I’m cool.
Note: I’d like to apologize in advance for the quality of the photos in this article. I must have messed up a setting on my camera, and I didn’t notice until it was too late. I cleaned them up as best I could in software, but many of them are really awful. I aim for a high bar on photo quality here, so my apologies.
First things first. If a computer has a case, it needs a badge on that case, right? I figured it was time Veronica had her own cool 1980s computer logo. Here’s what I came up with:
For best effect, look at it while imagining Wham wearing zebra-print spandex and rocking out in a New Coke commercial. Picturing it? Good. You may proceed.
I stalked eBay for a long time looking for the right Philco, and when it came along, I pounced. The trick here is getting one that you like, and also one that is the right size. They usually don’t list the dimensions in the eBay ads, and that information proved difficult to find online. Some of the eBay listings do have measurements, so if you read enough of them, you can start to cross-reference the sizes. The website PhilcoRadio is a great resource, with wonderful photos of every model ever produced. You can usually deduce dimensions from similar models built on the same chassis using the information from that site.
Here it is! I settled on the Model 42-327T, which was produced in 1942. This one isn't working and is missing a number of parts, so I don't feel too guilty about gutting it. It's really quite pretty. Philco made some damn fine things in their day.
First order of business is to pull out the innards. The whole thing is a single large unit held in with a couple of screws. There are tons of great components and elements here. Suffice it to say, I'll be using every part of this buffalo in the future. It's getting a place of honour on top of the junk pile.
Here's the reverse angle, with some clippers for scale. The metal ring around the outside is the antenna. The whole thing is very mechanical. There are ropes and pulleys for the knobs, the tuning capacitor is the big rotating-plate-air-dielectric style, and there are levers and ratchets everywhere for all the buttons. It's wonderfully made, and the mechanicals all still work, despite being seventy years old. Some of the vacuum tubes still look good, and have been replaced relatively recently. I'm sure I can find a use for those.
Now here’s where it gets really interesting. I think this thing really epitomizes the technological shift from mechanical stuff to electronic stuff. The mechanicals are fabulous, but the electronics are…. for lack of a better word…. amateur. Okay, okay, they get a lot of slack because Nineteen Forty Two. Someone probably listened to reports about D-Day on this thing. Still, it’s neat to see the contrast in sophistication with today’s electronics.
Look at it. JUST LOOK AT IT. It's like a Dick Tracy movie exploded in there. Near as I can tell, this is mostly original. The wiring is largely fabric-insulated, and everything is dead-bugged and soldered by hand. Poorly, I might add.
I couldn't resist a few macro shots of the electronics. I think I see six near-shorts in this corner alone. It's amazing anything could be built this way and have any kind of decent defect rate leaving the factory. I would expect the MTBF rate in the field to be poor as well, although its age and current condition seems to defy that.
Okay, one more, because I'm fascinated by this thing. I don't know anything about 1940s radios. Is this really how they were built, or has this thing been sloppily repaired by a dozen people over the years? I love the voltage divider hacked right on to the bottom of that rotary switch.
Okay, here we go! The guts are all removed, and seventy years of crud has been scrubbed out of it. The glass tuning panel above the speaker grill immediately caught my eye. It's held in by two clips, and is at a jaunty angle when viewed from the front. It's just perfect for a control panel, so that's what I'll be putting there.
After deciding I wanted my control panel to go where that glass tuning display is, I had my second flash of inspiration for this project. I realized I can etch the control panel as a PCB! It will be sturdy, easy to make, and the resulting copper colour will compliment the old radio perfectly. Huzzah! Okay okay, this idea is hardly original either, but let me have this one.
So, with that plan in mind, it was off to the drawing board. I took measurements from the glass panel, fired up Inkscape, and came up with this:
This is a low-res bitmap export from the vector file, just so you can see it here in the article. I used a much higher resolution one for printing and etching.
The font I’m using there is called Android Nation, and it’s by Nate Piekos. He makes great free-to-use (and paid) fonts. This one has the perfect 1980s look for our 1980s computer. If you’re interested, here’s the SVG vector file, and the PDF I generated to etch with. One trick with this is that the panel is almost 11″ wide. I don’t have any copper boards that big! You can buy them in large sizes, of course, but they’re expensive and I wanted to use what I have on hand. I split the panel in two and arranged it to fit on a standard 4×6 PCB. There will be a seam visible, but I figured it would be minimal. Besides, I will probably be making another one of these later, as I add or change controls. That’s the nice thing about this approach- it’s easy to change something in the SVG file, and just re-etch a new panel as needed.
Here's the panel finishing up in the photo-developer. I inverted one half such that the edges that meet in the middle won't be hand-cut. The join will be factory cut on both sides. I figured that would minimize the visible seam.
Let me take a quick sidebar to talk chemistry. Etching this board required quite a bit of solution (using my usual process), so I got to thinking about disposal. Some commenters on Hack-a-Day suggested that dropping aluminum foil into the used solution neutralizes it by (I believe) precipitating the copper back out. I couldn’t resist trying it.
Whoa! Check that out! The solution very quickly turns from a bright blue-green to a dull grey, and the foil gets covered in brown gunk. I suppose that's the copper? If you look closely in the lower part of the photo, you can see that the foil is really being eaten by this process. Look at all the tiny perforations in it! The reaction was also quite exothermic. The basin got very warm, and it smelled awful. I would describe it as "rotten vinegar"; the smell was bad enough that I had to move it outside and air out the house. I don't know if I "neutralized" anything here, but the whole mess went in the garbage can afterwards. Science!
Okay, enough faffing about. Back to business.
Here's the completed panel, etched, cut, and drilled. Above it is the acetate I used to expose it for etching.
For comparison, here's the radio's original tuning display. I did some test prints from Inkscape ahead of time to make sure that the sizes it claimed would be correct in real life. I wasn't about to etch this and find out the holes don't line up! For the record, Inkscape is in fact very accurate. It didn't need any scaling or fudging to print at the correct size.
As you can see, the seam turned out to be more visible than I had hoped. The factory-cut edges of the PCB don’t actually have copper flush to the very edge. I suspect that’s because some large guillotine machine is hacking them out of larger sheets. If I’d known the seam would be this visible, I would have worked it into the design better. It’s in a bit of an awkward spot here. Next time!
Okay, time to wire up this chica. The controls include all the ones I’ve been using on my test rigs up to this point. Left to right, they are:
CPU Run/Stop (1Mhz clock or single-step clock, respectively)
Slot 0 Allow/Deny. This is sort of a workaround, because the EEPROM programmer needs the system bus to itself during programming. Someday I’ll have a full bus arbitration circuit of some sort, which will make this switch unnecessary.
Here's the panel, all wired up. I'm using an old 34 pin boxed connector that I found in the junk pile. I probably should have checked that I have a matching plug before epoxying it to the panel. I managed to make a 38-pin plug fit with a little persuasion from a saw. There are a bunch of free pins on that connector, so I can add stuff later if I need to. Here you can also see that the two halves of the panel are epoxied together, with a toothpick in there for some strength. That joint failed during testing, and was redone with a paperclip (visible in the next photo). I also scratched-up the surfaces so the epoxy would grip better. The improved joint is holding well so far.
Here's the panel connected to Veronica. It's been a while since we've seen her! The cable to the panel is very long for good reason. It means that I can remove Veronica from her case and put her on the bench without disconnecting the control panel. I'll need her guts accessible for development, and I don't want to be removing that panel over and over.
If you’re really paying attention, you may have noticed Veronica seems to have lost weight. I’ve been making noise for a while about cutting the extra PCB off the backplane, and I finally did it. It was needed to make the case work out the way I wanted.
I masked the hell out of the backplane before trimming it down, because that fiberglass dust is really nasty. It gets in EVERYTHING.
One last detail to take care of. The radio I bought was missing the back panel. I wanted something light and easy to modify that would serve to keep the dust out. I ended up making one out of an old printer-paper box. There’s something poetic about this, since I’ve sworn off owning ink-jet printers. I no longer wish to be locked into their scam ink economy and fly-by-night drivers.
This may be the most useful thing that inkjet printer ever did for me. A curse on all your houses.
Here's the panel installed. It sits flush when closed, but it's hanging open a bit here. The two LEDs are the "programming" and "ready" lights on the EEPROM programmer. The rectangular hole is for access to the programming header. You might wonder why I didn't use a 90-degree header so it would be poking through the back nicely? Well, where were YOU with THAT idea three weeks ago when I could have used it?
Here's the back opened up. The folded edge of the printer paper box made a nice living hinge in the cardboard. You can also see why trimming the backplane PCB was needed. The back needs to sit flush with the circuit boards so that controls mounted on them can poke through. Because the back is cardboard, I can easily cut new holes as I add boards. Plenty of room to grow in here! Don't mind the breadboard standing up in the back- I'm experimenting with something there.
In that photo, you can see my third and final flash of inspiration on this project. The holes in the bottom are drilled large enough to fit an entire standoff, not just the screws. See those washers at the base of the standoffs? There’s another set of standoffs screwed in under those, sitting in holes in the case. This gives me the best of both worlds. For casual use, they are secure as-is and allow easy removal of the PCBs for development. For serious transportation, I can put screws in the bottom to hold those standoffs in place from the bottom. Simple!
Also, note how light shows through the etched portions of the control panel. That’s just screaming for some LED illumination, isn’t it?
Here it is from the front, all buttoned up! I'm really, really pleased with how this turned out, to be honest. It was way more work than I expected, but the best ideas always are. While assembling things, I noticed that the hole where the radio's mechanical pushbuttons used to be is actually the perfect size for a row of seven-segment displays. I've propped up HexOut in there to test the idea. So... yeah... THAT will be happening. Looks like I can fit eight or ten digits across there. Sweeeeet.
Here's Veronica running some code in her new home. Apologies again for this really awful picture. The display is showing the address bus, running an infinite loop at $FE10.
Obligatory glamour shot! Work it, Veronica, work it!
Well, this is exciting! I’m finally all set up to do some more electronics on her again. This was a lot of work, and many nights of waiting for glue and paint to dry, but it really needed to be done to start making forward progress again. I hope you enjoyed the ride!