Duncan Brown

I've been working at this from a few directions at once, switching when I get frustrated or bored with one and moving on to another. The switch is made by EBE but uses an industry standard naming scheme. MX 2/4x6 MX is the size (17mm), 2 is the number of wafers (ganged switches stacked one on top of another), 4 is the number of poles (electrically separate switches, though they all move together) and 6 is the number of detent positions. The switches have 12 possible detent positions, so by mechanically limiting it to 6, you can have two switches operating together around 180 degrees each of the wafer. Then with two wafers, that's where you get the 4 switches. There is a "common wire" ring for each wafer that the switch connects to each contact in turn as you spin the switch. The common ring has two breaks in it, to make two 180 degree common rings for each wafer. That's a standard off the shelf part. In this case, they wanted to use the same common wire (+5V) for two of the sets of switches, so they bridged those gaps again with solder. The upper switch (nearest the knob) has one part that sends the 5V into 4 places in that convoluted logic, to select the speed 50/25/N/12 - apparently the default behavior of the circuit with no 5V signal being applied to any of the gates, is to select the 8 speed. Since the last two positions have no wire attached, this is where I get the notion that the position below 8 is just 8 again. The other upper switch sends the 5V one place for 50/25 and another place for all the others. One of the lower switches does the same thing. This is clearly involved in the fact that my motor went a fast speed at either 50/25 or a slow speed at all other positions. It's like there is a different way the circuitry controls the motor for the upper two speeds. The lower switches use two different common wires, and send their selected signals off to more motor-y things, not the logic things, so I haven't chased that all down yet. I will note that there are a LOT of wires going into that motor case, so that's going to be a whole other level of complexity to tackle at some point. There are 3 7493 4-bit binary counter chips. The first one simply takes the input frequency from the crystal and divides it down. I think the net result of that is a 48KHz signal feeding most of the rest of the logic. The other two work together to divide down the frequencies even more, with various divisions fed into this convoluted logic in different ways, but the main clock input to those comes from the little daughterboard attached to this logic board, so that frequency changes with the positions of the switch. That daughterboard is labeled "oscillateur à rampe variable" which google tells me means "variable ramp oscillator" so that all makes sense. Unfortunately, the two chips on that board have no markings on top, whether on purpose or not I can't tell. So that will be interesting to figure out schematically, but I can certainly investigate it with an oscilloscope (if I get it all running again!) One thing that makes it hard to do all this is the fact that everything is plastered with a "conformal coating" - clear goo that hardens and seals all the exposed metal pins and leads and traces away from the elements. Great for longevity, not so great for connecting meter or scope probes to parts. The secret is to do it from the back, where all pointy leads and pins are easily reached through the thin and easily broken coating. But it makes for a lot of flipping boards over and back, which is where wires start breaking. There are two components on the logic board that look like wirewound resistors and are in series with the logic signals, which makes no sense unless they are delay lines - an analog method of making signals have the desired timing relationship. That would be weird, but this whole design is a little weird. I cannot measure any conductivity through them. I sure hope that doesn't mean the voltage from my multimeter torched them? That would also be weird and make no sense that 5V would be fine but 9V would be fatal...but in order to do a delay line you need a ton of very tiny wire, so anything is possible I suppose. More investigation needed on those. Duncan

Progress report: I've been slowly working through stuff, mostly on the top TTL logic board so far, making some progress. That's some convoluted logic there, that's for sure! I'd never run across a "3-2-2-3 AND-OR-INVERT" gate (7454) before. So far I've only broken off two wires (one of which I'm 100% sure I know where it goes, the other one I'll have to go back in my pictures and hope I can figure it out) and blown up one transistor, letting the magic smoke out (it's on the backplane board, and I hope when I remove it I'll be able to read a part number on it), which is pretty much how these things go, so all is well. But it's why I like having a spare in hand before I do this! Is there anyone out there who can explain to me why a knob with 5 marked positions (75/50/N/12/8) is attached to a switch that has 6 positions? I mean I guess it's way easier to buy a 6 position switch than a 5 position switch, but... As near as I can tell, electrically, it's basically a position under "8" that does the same thing as "8". Can anyone with one of these motors (that works!) verify that's how it behaves? Geeky details of what I've figured out in the next post, so you can skip that if it's going to make your eyes glaze over. Duncan

Some additional pictures I've taken along the way. One of the transistors that are mounted facing the board pulled up a bit so you can read the part number. And a bunch of the switch to document how all the fiddly little wires attach.

I'd actually be more likely to buy one if it didn't have the new logo on it. Surely there's no IP rights holder still enforcing their rights on the Eclair logo? Duncan

A little scoping around on that top board with all the SN84XXX series chips gives the expected results - the SN84L93 chips act just like a 7493 counter chip, so I still don't know what the 84 series is, but at least all my 74xxx data sheets will work. And those counter chips give more and more divided versions of the 1.536MHz source frequency. Interestingly there are some where the duty cycle is wacky and the frequency is not divided precisely; that may be part of the root cause of the motor running a bit slow and/or the fact that it will only run at 2 different speeds. I'll know more once I trace out the complete circuit, but this gives me an idea of where it might be going wrong. Luckily, this frequency-dividing circuitry just runs freely when the circuits are powered up, regardless of whether the drive part of the motor has been told to be on or not, so I can work on this without the motor flailing the whole time. Duncan

Huh - turns out I already have a DVXUser account which hadn't been logged in to since 2009. Had to answer a couple of old questions in my inbox ? We'll see if I have any better luck there. Duncan

It's an easter egg! Too bad there is no secret button code to access it... Duncan

I suspected the 1536000 Hz crystal was chosen because it divided evenly for all their speeds. Sure enough! I did the math so you don't have to: 8fps = divide by 192000 12fps = divide by 128000 24fps = divide by 64000 25fps = divide by 61440 50fps = divide by 30720 75fps = divide by 20480 Duncan

State secrets. Need-to-know basis. If I recreate them, I will probably be whisked off to The Village. (Be Seeing You!) Duncan

Do we know for sure they built the entire motor? Their name is on the actual motor component, but I suspect anyone could purchase motors from them. There is no question this was built using "mil-spec" parts though. I'm still trying to figure out what the Texas Instruments 84xxx series of chips is. I'm sure they are equivalent in function to the same numbered 74xxx series parts, and their official mil-spec versions were the 54xxx series. Might have to go dig my old TI data books out of a box. Duncan

Next, I will have to say that the idea of not even bothering to troubleshooting the circuitry, and just replacing it, is appealing. I historically fix things back to their original state, rather than improving them. As an example, I'm building up a series of 1970s pinball machine designs that were thought to be lost to history, and I am doing it with the original technology - relays, stepper units, etc, rather than taking the easy route and throwing a computer controller in each one. But this positively stone-age digital technology (double sided boards, through-hole components, TTL logic chips, giant crystal) could largely be replaced with a board the size of a postage stamp, possibly with less effort than trying to understand and repair what's currently there. The only hard part might be the motor driver circuitry, but that's already there and presumably in OK shape, given the behavior of the motor. But I will make a first stab at documentation, troubleshooting, and repair. The motor currently only has two speeds (very slow and very fast) depending on the position of the dial, neither one of which is synced properly (the light stays on, and my phone tachometer app shows them not to be precisely on any expected speed.) My first thought was that the switch wipers on the circuit boards were crudded up...only to open it up and find a sealed, expensive switch that's probably good for millions of operations... so that's probably not going to be the problem. Then I thought the problem must be with the circuit board connectors. For repairability reasons I am very thankful they connectorized the boards, but over decades of lmicrovibrations, connector contact points can fail - usually fixed with nothing more than unplugging and replugging them. But then I see they used gold-plated tooled pin and socket connectors. It's still possible a connector failed, but far less likely with those. In other words, this beast was very well made, sparing no expense, and designed with harsh environments and decades of use in mind. Well done, Eclair. Duncan

First, I sometimes forget that not everyone is as old as dirt, like I am, so they may not get the title reference. See attached. Duncan

The topic name is overselling it at the moment - all I have right now are pictures of the guts. But as I get farther with schematics, parts identification, troubleshooting, etc. I'll add it here. I hope it goes without saying that you SHOULD NOT disassemble your motor like I'm doing here. I am a little skilled at these things and I also have little to lose - the motor was not functioning correctly. I'm hoping I can get it running properly again, but if not, I was looking at buying another motor anyway. Duncan

Keep in mind that when a lot of these things were in service, SAE 30 oil was just "motor oil" and there weren't all these choices. It was used in engines, in little pump cans for squirting into oiling tubes and holes, for making door hinges less squeaky, for just about anything. In many cases that really does mean it doesn't much matter. Oilite bushings are pretty crude old-school technology; I think any light oil would impregnate the bushing and work for a decade or two. The only time I ever ran into a problem using modern oils in place of SAE 30 was in the dashpots of the SU carbs of my TR4 decades ago when I drove one. The performance was predicated on the way SAE 30 changed with temperature, and it got very wacky when I used 10W30 instead. Duncan

Good idea - thanks! Duncan

Really? No ACL bits hanging around gathering dust? I'm solving the connector needs other ways, but I'm still looking for everything else. Seriously, sell me your broken motor, then I can take apart my broken motor and maybe get one working between the two. Duncan

I asked him, if all that old equipment was valueless, if he'd sell me the motor cheaply ? Apparently he was fixing it for someone else, so that explains his lack of Eclair info - seems like his own interest was with other brands (including Russian ones, naturally.) The starfield background was so late 90's. Duncan

Interestingly my home network blocks that site as dangerous and tells me to "contact the network administrator" - I AM the network administrator! I wonder if Comcast is blocking all of Russia or something. Duncan

Circling back to this after a long drawn out process... He's willing to sell the schematics. Oddly, he charges per page, so at 20 Euros per page it would be 100 Euros for the whole set. He was willing to discount that for me, but in the end there was no way for me to pay him, given everything that's going on with sanctions against Russia right now. (We tried several options but nothing worked.) I'll try again if/when the sanctions are lifted. He apparently used to design and build all kinds of accessories for film movie cameras (The Aapo of Russia!) but is convinced that is all worthless now with the death of film. (I tried to convince him that "it's not dead yet!") Here is an older website of his that he pointed me to. Interesting stuff. I'm going to give it a NSFW warning both because of the random nearly-naked female picture there for reasons that aren't clear, and because the web design is 1990's GeoCities style, which might shock you if you weren't on the web in those days ? http://pouch.narod.ru/ Duncan

Yeah, that's not how those work. Duncan