Well, I managed to find the very basic design of the control dial, all I need now are the numbers. These can be gained without opening up your dial control. All you need is a multi-meter capable of measuring resistance values and a protractor 😀. I don't know if the plug is 2 connector or 3 connector, but the images of the ACM suggests 3.

Basically what is needed is the minimum and maximum resistances between each connector with the dial at both extremes (as far as possible clockwise or right, and counter clockwise or left,) for a total of 6 numbers. Though, one pair of numbers should be identical, and the other two pairs of numbers should mirror each other. The only other number is an approximation of the range of motion in degrees (that's what the protractor is for.) I imagine that none of the numbers has to be exactly precise. If you want to be completely thorough, measurements at regular intervals would also be appreciated 😀 That would be a measurement taken with the dial set to each mark around the dial. Also helpful, would be if the dial switches fully "off" and/or fully "on" - this is usually signified by an increased resistance at either end, followed by a click. Fully "off" would completely disconnect, while fully "on" would short the connection. If this is the case, measurements pre and post click are really needed.

The three points would be tip-middle, tip-inner, and middle-inner. chances are that one of those will be the same regardless of where the dial is, and would either be infinite (no connection,) or match the maximum setting of the other 2 measurement points. Lets assume that middle-inner is the one that doesn't change and is 1kOhm (1 kilo-Ohm - can't find the Ohm symbol, and the number is probably higher than that.) Then the measurements for tip-middle could range from 10 Ohm (again, an arbitrary number,) with the dial all the way left and 1 kOhm with it all the way to the right. The final set (tip-inner,) could be 1kOhm when all the way left, and 10 Ohm when all the way right.

The reason that stepped measurements are preferred, is that some pots do not have a steady increase in resistance as the dial is turned. If it does (have a steady increase,) then you can save yourself some typing by just giving the low & high end values 😀 But some will increase slowly at first, and faster later on. So, the change from 0 to 1 (counting marks around the dial,) could be 10 Ohm, then the change from 1 to 2 could be 20 Ohm, then 40, etc... Also, it cannot be assumed that the lowest setting is 0. There might be a current control resister added to protect from accidental shorts in the pot. Though if a fully "on" position is provided (click to short,) then that protection is probably on the board.

For those interested, the way the circuit works:

A capacitor is added into the circuit that basically cuts the current until fully charged, then it discharges. This introduces a delay in the current flow. The capacitor is fed current in 2 parallel lines. One line is a fixed resistance, while the other is variable. The higher the resistance on the variable line, the longer it takes the capacitor to discharge (the longer the delay.) I don't know how the cards are actually designed, but if I was doing it, I would have put both lines on the external dial. With a circuit on the board to detect when it wasn't plugged in, to kick in a default (or maybe calculated,) delay setting. By putting both lines on the dial, higher resistances could be provided for even faster systems in the future. But I doubt they did that, considering the patent design states that the 3rd connector isn't used. That's looking at the patent assigned to Creative Labs in 1999 (I honestly thought it came out before that.)

p.s. Oops, hit submit to soon.... Also helpful would be which board the numbers are for. Thrustmaster ACM, Gravis Eliminator, or some other board I don't currently know about.

Thank in advance for anyone willing to take these measurements for me (and anyone else on this board that needs them.) 😀

Just post good (as in not blurry) scans or photos of both sides of the card and I'll see what my crystall ball can do.

Usually the compensation just adjusts the NE558 comparator reference voltage.

Jepael wrote:

Just post good (as in not blurry) scans or photos of both sides of the card and I'll see what my crystall ball can do.

Usually the compensation just adjusts the NE558 comparator reference voltage.

I don't yet own one. They are pretty useless without the dial. The only one I found so far that included the dial, and was within the budget I'm willing to pay for it (considering I only have one game that "might" be fixed with it so far,) sold on me 🙁 If I can get the stats on the dial, I'd be willing to get one of the inexpensive ones that don't have a dial. Knowing how they work now, I'd be willing to risk guessing at the numbers, but I'd still need to know how they were connected(center power, center ground, center v-resistance, etc...)

Is it sure that they are useless without the external pot? What if it works at some default setting without the pot?

The connector on the cards is 3-pole definitely. And google image search revealed the external pot device has also 3-pole connector. One option is that all three are directly connected to a pot. But 3 poles might also mean two are used for the resistance and one is the switch whether the connector is inserted or not. In either case it could still work without the pot, if it is only for fine tuning some default setting.

If you take a look at the card, you will see that it has a place for onboard pot, so it would be easy track if the onboard pot connections are just wired to the connector as-is, and also it will reveal how the pot is connected. Only thing missing would be what the actual pot resistance is (and if it is linear or log type).

So I would not worry too much if the external pot does not come with the card, it should be easy to replace. Or even bypass to what should be the default reference voltage for the NE558.

Jepael wrote:

Is it sure that they are useless without the external pot? What if it works at some default setting without the pot? […]
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Is it sure that they are useless without the external pot? What if it works at some default setting without the pot?

The connector on the cards is 3-pole definitely. And google image search revealed the external pot device has also 3-pole connector. One option is that all three are directly connected to a pot. But 3 poles might also mean two are used for the resistance and one is the switch whether the connector is inserted or not. In either case it could still work without the pot, if it is only for fine tuning some default setting.

If you take a look at the card, you will see that it has a place for onboard pot, so it would be easy track if the onboard pot connections are just wired to the connector as-is, and also it will reveal how the pot is connected. Only thing missing would be what the actual pot resistance is (and if it is linear or log type).

So I would not worry too much if the external pot does not come with the card, it should be easy to replace. Or even bypass to what should be the default reference voltage for the NE558.

Well, useless is probably not the best term... Better to say a waste of funds unless I can get/replace the dial. From what I've been reading, my AWE32 would actually perform better than the ACM without the adjustment dial. The card doesn't seem to have adjusting circuitry other than what the dial provides.

I have been looking at alternative cards as well. As for cards with dials there is also the "Gravis Eliminator Game Card." Though the ACM seems to have better support for faster systems. The Eliminator seems to cap out at 33Mhz, while the ACM states "for 486 and Pentium systems." I do remember that when I had an ACM in the past (I really wish I had kept the blasted thing,) I used it on a 400Mhz system (I believe.) It was in a much older "modern" system at the time. My 233Mhz system didn't have a problem, but my faster Windows 2000 system did. The next time I replaced that system, the ACM card went with the old one when I sold it 🙁

I've also become extremely interested in software adjustable cards too now 😀 No dial, just a command that sets the card before playing a game that's sensitive. The 2 software controlled ones I know about are "Kraft Software Controlled Game Card" and "CH Game Card III". Of the 2, the Kraft card has the widest range of settings (1-99,) compared to the CH card's (1-31 & 150.) Still trying to figure out the jump from 31 to 150 there. I'm searching for manual scans & reviews of the cards now. If it turns out that I do need a card, I'm seriously considering holding out for one of those.

It may all be moot, though. I've been putting older games on the system as I find them. So far, Wing Commander Armada is the only game that has given me any joystick issues. In writing a Joystick to Keyboard game loader (so I can use the coolie hat on my Thrustmaster in X-Wing & Tie Fighter floppy,) I thought I had confirmed that I didn't need the card. When I used a timed loop read of the port it stays accurate. But if I use the BIOS INT routines to read it, the numbers change significantly when the game is running. Using a timed loop to read is "supposed" to be the method that is susceptible to the joystick polling speed issues. Which is why I spent days trying to get the BIOS read method to work. I only switched to the timed loop out of desperation. When it worked, and continued to work, I figured the AWE32 was OK with the faster system speeds.

I've asked in another tread about Wing Commander Armada, but no responses so far. I'm on a fixed income, and I'd rather not buy something that I don't actually need. Also, I have cards, drives, boards, etc. maybe 50-100 PC parts already that I don't have a current use for. I would sort of like to limit the growth of that stockpile a bit if I can 😀 If you (or anyone else reading this thread,) know of games that are exceptionally sensitive to joystick polling speeds, I'd love a list. That would let me skip straight to finding/testing games I know should have a problem. Wing Commander Armada seems to have joystick issues, even when run in DOSBox with the cycles set low enough to very closely approximate system speeds of the time. Maybe it's just Armada being a spoiled princess 😀

Well, I'll be able to post those specs myself in a while 😀 Just got one complete in box for $12.99 (with shipping.) So, I'll know if it will fix my problem or not in a week or so. I'll take those measurements myself and post them when it comes in. I'll also see what I can figure out through examination. The dial numbers won't be exact though, as I only have an analog meter now 🙁 My digital one fried... Or rather got fried on me.

Well, got the card in and dug out my multi-meter. It's analog only, so the numbers are extremely soft. Really need a digital meter to get accurate numbers.

All the way to left (1):
* Tip to Middle ring - ~1.2 kOhm
* Middle ring to Inner - ~220 Ohm
* Tip to Inner Ring - ~1.8 kOhm

All the way to right (10):
* Tip to Middle ring - ~1.4 Ohm
* Middle ring to Inner - ~1.8 kOhm
* Tip to Inner Ring - ~1.8 kOhm

Middle setting (5):
* Tip to Middle ring - ~700 Ohm
* Middle ring to Inner - ~700 Ohm
* Tip to Inner ring - 1.8 kOhm.

True Middle (5.5): *** There isn't a 0, so 1 + 4.5 and 10 - 4.5 ***
* Tip to Middle ring - ~600 Ohm
* Middle ring to Inner - ~900 Ohm
* Tip to Inner ring - ~1.8 kOhm

It looks like a linear pot with at least 2 small resistors added in. The smaller the value the closer to accurate they are (thus is the nature of analog meters.) So the 1.4 Ohm is fairly accurate, as is the 220 Ohm (though less so than the 1.4.) The 600 & 700 Ohm measurements should be fairly close as well. The 900 Ohm & higher were getting to the point where the markers were getting extremely close to each other. Thus, accuracy suffered greatly.

Looking at the card, it looks like one of the poles is connected to ground (the 2 black wires,) while the tip is connected to the red wire (usually + voltage,) and the middle ring is connected to the blue wire (varies from device to device.) With 2 black wires, it looks like the card measures tip to inner (which would be constant,) & middle to inner (which would vary from 220 to 1800 Ohms.) Though it could very easily also measure tip to middle (1.4 to 1200 Ohms.)

Will try to get a digital meter and get better measurements.

Oh, on a side note, the card didn't fix Wing Commander Armada. So, unless something comes up showing I need it anyways, I'll probably be selling it in a month or so. Guess Armada is just broken 🙁 I've tried slowing my system down, but the problem just won't go away.

Actually opened up the dial box, and the wiring is a little different than I expected. First, the POT has 4 connections, not 3. The 4th seems to be to the casing. In circuit design, this would usually be connected to ground. In this case it is connected directly to the inner ring on the plug. The inner ring is also connected with post #3 through a 220 Ohm resistor. The tip is connected to post #1 and the middle ring is connected to post #2. The POT itself is listed as a 1K Ohm (marked B1K,) but actually measures as a 1.2K Ohm.

Based on the numbers, cheap (+/- 20% at least,) parts are used, which isn't really that much of a surprise. High cost parts aren't really needed for the functionality in question. So, it probably calls for a 1K Ohm POT and a 200 Ohm resistor. Use a standard 1/4" stereo plug. Connect the tip directly to post #1. Connect the middle ring directly to post #2. Connect the inner ring directly to the casing (ground,) and through a 200 Ohm resister to post #3. That should get you a working speed control dial.

I've also attached a WinImage created image of the drivers disk here. Don't have my scanner up and working or I would scan the manual and include it as well. Really should scan that before I sell the card I guess. Hoping to get $20 + shipping for it, based on other asking prices for it, and would get me a fair profit on the exchange 😀 Will probably start the auction at $10 (break even,) and keep my fingers crossed. The guy I bought it from really had it underpriced, but I probably wouldn't have bought it otherwise.

I have one of these cards without the dial. I meant to post a picture of it after someone asked, but then I forgot about the thread. Sorry.
Thanks for posting your findings on how the dial works. I lost that dial about 100 years ago.
To see the effect of speed adjustments, I used to use NASCAR Racing. The calibration screen shows the range of readings that the game is seeing. There should also be simpler, freely available applications just for that purpose. Even QBASIC can do it, if necessary. 😀
If you can get a numerical reading of the joystick range, maybe compare that with the readings on a machine where Wing Commander works, if any.

Thanks for the disk image, I have one of these boxed coming in soon but I dunno yet if the included disk is any good 😀