On the workbench for some troubleshooting is a 1950s era vintage RCA Victor 45-EY-3 record player. It belongs to someone in my neighbourhood and came to me via a referral from a neighbour who’s familiar with my penchant for tinkering with electronics.
RCA Victor 45-EY-3 record player from 1950RCA Victor 45-EY-3 record player from 1950RCA Victor 45-EY-3 record player from 1950
The owner purchased this recently and had already replaced the tubes, capacitors, a few resistors and some of the mechanical bits before the record player landed on my bench. He said it was sort of working (some mechanical issues with the arm moving), but then stopped turning on. Fortunately, he had a printouts of the service documentation available to look over. On the electronics side, the circuitry is pretty simple consisting of three tubes: rectifier (35W4), amplifier (12AV6), and output (50C5).
RCA Victor 45-EY-3 schematic
After touching up a few solder joints, I found the power switch was kind of dodgy and would work if I tilted it a certain way. I also realigned the muting switch (S2) so that it was oriented the same way as one of the photos in the service manual. That got me to the point where records could play and sound came out of the speaker instead of just resonating through the needle arm. The sound volume was pretty low though, even with the volume pot turned up all the way and there’s also a lot of hum getting into the electronics too. Those are the two main things I need to work on, and the owner will work on the mechanical stuff.
Finally, after almost a year, my PhD diploma is in a proper frame and is hanging on the wall!
PhD diploma in a nice frame
The frame came with some interesting mounting hardware. The plastic hangers have a pointy part on the wall side. Insert those into the key hole hangers on the frame side, put the frame up against the wall where you want to hang it, and press against the wall. The pointy part leaves a little dimple in the drywall right where the plastic hangers need to be nailed. Take the plastic hangers off the frame, nail it to the wall where the dimple is, and then hang the frame.
Pretty clever.
PhD diploma hanging on the wall.
Now I have it hanging on the wall above my computer. Looks pretty good there.
I have a long history of dabbling with emacs, having discovered it during my latter undergrad years (the emacs 18 era). I’d pick it up for a while, and then go back to whatever editor I happened to be using at the time. I liked emacs, but using it wasn’t anything that ever really stuck with me. Part of the reason was that I didn’t really have a solid use case for something like emacs. Emacs also has a not-so insignificant learning curve and getting into it can be pretty overwhelming and intimidating.
When I started on the PhD, I made a concerted effort to make emacs one of my primary tools, having learned about things like org-mode and distributions like spacemacs and doom-emacs from other people.
Org-mode makes setting up something like a research notebook pretty easy, and getting started is pretty simple. The basics are pretty easy to learn and when you want to do something more advanced, the documentation is very good.
Now, after spending the past couple of years of using emacs routinely, I’ve decided it’s time to learn more and start crafting my own emacs configuration. I’ll get to learn a little more elisp and dive into some of the packages I’ve become used to using. Might be something I keep and continue to evolve, or I might go back to spacemacs. Maybe I’ll try something else later.
It feels kind of like when a Jedi reaches the point in their training when they make their own light saber.
My initial plan was to use a project enclosure to build a new joystick out of, but it turned out to be a bit too small and felt awkward. Then I looked around and saw an old lap desk that I wasn’t using anymore and thought “Oooh, that might work.”
The lap desk was originally designed to have a little pouch for carrying things like paper and writing implements in. Perfect for containing the wiring and components. The innards of the lap desk was accessible via a few zippers (two “pouches” contained inserts with styrofoam beads for padding and a middle pouch for stashing things in). Used a hole saw to make a few holes for the joystick controller and two buttons so that the “lap joystick” could be used left or right handed.
Joystick controller installed on the lap desk
The joystick controller and buttons went in very nicely.
Buttons added to the lap joystick
Buttons added to the lap joystick
To wire everything up, I started with a piece of copper clad PCB hot-glued to the back for a base. I thought some MeSquares would make good spots to wire up the joystick and buttons to the cable that connects to the Atari. A terminal connector was used for the common connection. I was originally going to just solder the common connections to the copper clad, but my soldering iron turned out to be too puny and ineffective for soldering onto a copper clad heat sink. The cable from one of the dead joysticks was used to connect to the Atari console.
Getting the joystick and buttons wired up
The wiring is pretty ugly and I’ll probably re-do it at some point to make it neater but the lap joystick works perfectly with the Atari, and it’s actually pretty comfortable to use. The cable out to the console ended up being kind of on the short side (it’s not that long to begin with), so the console has to be pretty close to play. When I re-wire everything, I’ll see if I can extend that out a bit.
I’ve got one more joystick controller and will need to get a couple more buttons to build a second lap joystick. I think I’ll see if I can find some shorter buttons to use.
Like the 8000A, there’s a label on the bottom that lists the specs and configuration. This unit came with the rechargeable battery option, which would explain the extra heft.
Fluke 8600A specification label
Unfortunately, this one didn’t do anything when the power button was pressed. Getting the cover off the DMM is a simple matter of removing one screw just above the power connector (normally covered by a “Calibration void if removed” type sticker).
The insides are a considerably more complex than the 8000A. A large chunk of the space toward the transformer and power plug end of the board are taken up by the rechargeable batteries. This DMM appears to have had some modifications or repairs made to it.
Inside the Fluke 8600A digital multimeter
A cursory inspection shows one significant issue: leaked batteries.
Leaky NiCad batteries
At some point, one of the D-cell NiCad batteries was replaced with an AA sized NiCad battery.
Replaced battery
Replaced battery
The manual I found (dated 1981) says the batteries can be replaced, but the ones in this unit have been tack soldered to the terminals. Perhaps the battery options were changed in later models of the meter.
Another IC (possibly a ROM) was also added to the meter and connected to the board with some ribbon cable. The ribbon cable is soldered to a DM47S188AN (256 bit PROM) and the mystery IC is just attached to the RF shield of one of the daughter boards with some electrical tape. Maybe a repair job, or a modification?
Mystery ROM
Mystery ROM connection
There are four daughter boards in the case that attach to the main board via pin and socket connectors. One board is marked as a battery power supply, which I’d guess takes care of charging the NiCad batteries.
Battery power supply board
Board #2 is marked “OHMS CONV ASSY”
Ohms converter board
Ohms converter board
Board #3 was marked “INPUT DIV”
Input divider board
Board #4 was a fairly large one with a large shield on it. No clear silkscreen markings labeling the board like the others but according to the manual, it’s the AC converter board. it also had a holder for a spare fuse. Very thoughtful.
AC converter board
Other than the batteries, I don’t see any obvious problems with any of the other components in the meter. I’m thinking maybe if pull out the leaked batteries, that might get the meter running but I’ll need to study the schematics to see how the batteries are connected to everything to figure out if that will work. This thread on the EEVBlog forum has some potentially useful information.
I’ll put this with the rest of the project items in the stack.
