Yet Another Masterplay Clone

[thegamezmaster]

Very nice work. Are they being sold completed or just the circuit board? Sorry if this a dumb question but might be interested in a completed one if anyone is offering them

Edited October 14, 2018 by thegamezmaster

[+DrVenkman]

So if I'm reading the schematic right, pin 9 is the second FIRE button? Excellent, as that corresponds to the Genesis 3-button pad. I've got two of them to use on my 7800 via an Edladdin Seagull '78 adapter. Defender is gonna rock.

[fandenivoldsk]

I would also like two boards. Thanks!

[smbaker]

Current list is:

drvenkman - 2 boards

airshack - 2 boards

john_q_atart - 2 boards

protestarti - 2 boards

swami - 2 boards

rayik - 2 boards

fandenivoldsk - 2 boards

 

I do have boards ready to mail. If you've ordered boards from me before, the cost and shipping will be the same as before ($10 per board, plus shipping). If you haven't ordered from me before, then PM me with your address and I can calculate you a shipping amount.

 

Scott

[rayik]

Just sent PayPal for 2 boards. More parts to order. I'm thinking of building these in a case. Thank you Scott

[+DrVenkman]

Current list is:

drvenkman - 2 boards

…

 

Boards arrived today. Thanks, Scott!

 

 

With luck, my parts will arrive from Digikey tomorrow or Friday.

[smbaker]

At this point, all boards have been allocated to orders and I'm sold out. I'll get some more on hand soon.

 

Scott

[+DrVenkman]

Parts arrived today but worked has drained my brain dry ... I hope to get my boards built tomorrow night. VERY much looking forward to Pac-Man and Ms. Pac-Man with my TAC-2.

[+DrVenkman]

Okay, I built my first board tonight but something's not right. The joystick only registers up up (North per the schematic) and left (West) movements. Down (South ) and right (East) aren't registered at all. However, when tested with something like Missile Command, the cursor returns to center position as expected. I've reflowed all the solder joints and I don't have any solder bridges or damaged traces.

 

Does anyone have any suggestions on what might be amiss? I haven't yet swapped the IC switch but that's probably going to be the first thing I try tomorrow.

Edited October 20, 2018 by DrVenkman

[smbaker]

If you have a multimeter, I would start by checking to make sure the IC is getting power. It gets 5V from pin 12 of the DB-15, and supplies 5V to pins 12 and 13 of the IC. Ground comes from pin 15 on the DB-15 and is present on pins 4 and 5 of the IC.

 

The first time I built this, I had an issue with the 5V line, and it caused the type of behavior you're seeing.

 

I'd also suggest verifying diode polarity (I have no idea what would happen if you put them in backward, but it seems the most likely component to install backward).

 

Scott

[+DrVenkman]

If you have a multimeter, I would start by checking to make sure the IC is getting power. It gets 5V from pin 12 of the DB-15, and supplies 5V to pins 12 and 13 of the IC. Ground comes from pin 15 on the DB-15 and is present on pins 4 and 5 of the IC.

 

The first time I built this, I had an issue with the 5V line, and it caused the type of behavior you're seeing.

 

I'd also suggest verifying diode polarity (I have no idea what would happen if you put them in backward, but it seems the most likely component to install backward).

 

Scott

 

Thanks, Scott. Will do! I know the diodes are installed correctly, but I'll definitely check the 5V line later this morning.

[+DrVenkman]

Okay, I've verified 5V on pins 12 and 13 (4.95V, actually) and ground on both pins 4 and 5. I've also tried swapping the analog switch IC (I bought parts for 2 boards). Still no-go. I even tried one of my thumbsticks in port 1 and the Masterplay in port 2 for a two player game of Pac-Man, just to see if it's an issue with one controller port. Same thing - up and left work, right and down do not when plugged into port 2 (I even used a second 15-pin extension cable).

 

I've verified my resistors too - read the color bands myself and measured some of the same lots I used, all within tolerances advertised. Diodes installed with the cathode (indicated by the black band) to the right as you look down, in accordance with the silk screen markings.

 

I've tested with both a Genesis pad ("C" button works great as a FIRE 2, by the way ), and my TAC-2, I can also test with CX-40s and a WICO Command Control but I don't think the joystick type is the issue. Keypad buttons all work, as does the second board-mounted FIRE2.

 

So I'm kind of at a loss here.

 

EDIT: I had a thought: can the trimmer pots be installed backward? Or alternately, can they be so out of adjustment one way or the other that they prevent the Down/Left circuit from reading properly? The schematic doesn't seem so, but it's been a long damn time since my one year of required "EE-for-non-EE-majors."

 

(Pardon the cat hair - one of my orange lummoxes jumped into my lap as I was trying to take bright light closeups. Also haven't cleaned the board after assembly yet so there's some clear flux droplets visible from the solder).

 

 

 

 

Edited October 20, 2018 by DrVenkman

[smbaker]

It shouldn't be possible to install the trimmers backward. They should only control the center point, and according to your post the center point is working correctly. When I install fresh pots, they were well out of adjustment -- I assume you adjusted them using Pete's test cartridge or similar until they centered up?

 

Everything in your build looks correct, when compared to mine.

 

I would suggest trying with the CX-40 just to ensure that there's no issue with the joystick, though looking at a TAC-2 teardown on the web it looks like all should be fine with that stick.

 

Is your console a 2-port or a 4-port? I generally test using a 4-port, but I can dig out my 2-port and try on that.

 

Scott

[john_q_atari]

I'm guessing you don't have Petes test cartridge or a flash cart to load the image onto? That cartridge has been very useful to me when it come to controllers.

[+DrVenkman]

It shouldn't be possible to install the trimmers backward. They should only control the center point, and according to your post the center point is working correctly. When I install fresh pots, they were well out of adjustment -- I assume you adjusted them using Pete's test cartridge or similar until they centered up?

 

Everything in your build looks correct, when compared to mine.

 

I would suggest trying with the CX-40 just to ensure that there's no issue with the joystick, though looking at a TAC-2 teardown on the web it looks like all should be fine with that stick.

 

Is your console a 2-port or a 4-port? I generally test using a 4-port, but I can dig out my 2-port and try on that.

 

Scott

 

I've got two 4-port units that are otherwise working correctly so far as I know. Games play correctly with the thumbstick controllers I built, and acceptably well with the two CX-52's I've cleaned and half-way refurbed. Trak-Ball games work great.

 

I'm guessing you don't have Petes test cartridge or a flash cart to load the image onto? That cartridge has been very useful to me when it come to controllers.

 

No Pete's here, and no AtariMax, but I plan to order a copy of the test cart next week.

 

Is there a decent alternative game to try to use to adjust the trimmer pots? I messed with the X-axis pot earlier and got unsatisfactory results - for instance, I turned it so far that the ship in Galaxian or the character in Pac-Man would move right un-commanded, and only left when I moved the stick. But when I adjusted the trimmer back in the other direction so that the sprite doesn't move without joystick input, the right directional still didn't seem to register.

[smbaker]

Part of the problem is that I think some of these games automatically try to calibrate to the controller. For example when I start Galaxian with my handheld controller sometimes it pulls one way or the other until I move the stick back and forth a few times. So it might mess with any attempt to adjust the pot.

 

One would think of the games, Missile Command would be the ideal one to try to use to adjust the pots, but maybe it too is exhibiting some funny business.

 

Let me take a multimeter to my controller and see if I can get you some baseline numbers for what you should adjust your pots to.

 

Scott

[smbaker]

Okay, I've done some measurements. With the power removed and the IC removed, I measured across the two-pin footprint that's adjacent to each pot. These are marked JP3 and JP2 on the schematic respectively, but are unmarked on the PCB.

 

For the top pot I measured 265 K ohms. For the bottom pot I measured 263 K ohms.

 

I also tried to reproduce your issue by intentionally setting the pots out of bounds and trying missile command, but I was unable to reproduce it.

 

Scott

Edited October 20, 2018 by smbaker

[+DrVenkman]

Okay, I've done some measurements. With the power removed and the IC removed, I measured across the two-pin footprint that's adjacent to each pot. These are marked JP3 and JP2 on the schematic respectively, but are unmarked on the PCB.

 

For the top pot I measured 265 K ohms. For the bottom pot I measured 263 K ohms.

 

I also tried to reproduce your issue by intentionally setting the pots out of bounds and trying missile command, but I was unable to reproduce it.

 

Scott

 

Thanks, Scott. I'm heading out to the bench for some adjustments and then some tests.

[+DrVenkman]

So, some tiny progress of sorts ...

 

With both power removed and the IC pulled, I measured the trimmer pots - R10 (the top pot) was nearly 600K ohms and R9 (the bottom one) was just about maxed out at 990+K ohms. I adjusted them both to approxminately 265 K ohms and got this with Missile Command (pardon the background noise - I had a TV going in the other room & forgot to mute it).

 

 

With the pots set like this, Galaxian moves right uncommanded by the stick, though moving the stick left does work. Pac-Man seems to automagically move up at every intersection regardless of stick direction. No response to down or right commands, still. I am wondering if I need to pull the 10M ohm resistors and replace them, just to see if it makes a difference.

[smbaker]

 

With the pots set like this, Galaxian moves right uncommanded by the stick, though moving the stick left does work. Pac-Man seems to automagically move up at every intersection regardless of stick direction. No response to down or right commands, still. I am wondering if I need to pull the 10M ohm resistors and replace them, just to see if it makes a difference.

 

If you have something lesser, say around 500K, I would be curious if substituting those for the 10M resistors would make a difference. I based this on low_budget's design, and he used 10M, and they worked for me so I never thought any more about it. But it does seem really high to me.

 

ETA: I just tried jumpering a 470K in parallel with each 10M resistor, which according to the calculator should lead to an effective resistance of approximately 448K. I had to readjust the centering pots to compensate, but everything continued to work fine. Depending on what you have in your junk box (if you're lucky enough to have a junk box), you can try any resistor that's around 470K or larger. Go any smaller than that and you'd start to lose the high side of the range.

 

Scott

Edited October 20, 2018 by smbaker

[+DrVenkman]

Thanks for all the effort you're putting into this, Scott. I do have plenty of resistors, so no worries on that score.

 

I removed the 10M resistors and replaced them each 560K resistors. Unfortunately, it made no real difference. I really can't figure out what's going on now since my other controllers are working okay, otherwise I'd think it would be my 5200 at this point. It's gotta be something just completely basic. I even checked all the pins on the connectors for solder flakes, sprayed the board with canned air for debris, etc. Nada.

[smbaker]

Unfortunately, I don't have any good ideas left. I'd like to get to the bottom of it, especially considering whatever happened to you could happen to others. If there is an issue with the design where it doesn't work with some 5200s for some reason, would be good to know. I did try it with my 2-port, and it works fine there for me also.

 

Did you buy all of your parts from digikey?

 

Scott

[+DrVenkman]

Man, even my two crap-tastic CX-52's work fine with Defender, but still only up and/or left with my Masterplay clone. I just tested everything again with my thumb sticks and my Trak-Ball for Centipede, Missile Command and Millipede, so I'm disinclined to think anything is wrong with my 5200. Looking at the board schematic, is there any one thing that could be shorted or not making good enough contact that it would affect both axes this way?

 

Scott - you posted I was posting as well. I bought everything except the resistors, caps and jumper pins from Digikey. I did verify resistor values before I installed them, and measured capacitance of the little 0.1uF ceramic cap (came out to 0.0998 uF). Unless both analog switches are defective I have no idea what can be going on. Another data point: I can rub my fingers all over the bare contacts under the board and change resistance enough to trigger right and down movements, just not with a joystick or gamepad connected to the 9-pin connector. It's all very, very mysterious.

[smbaker]

I can't think of any single thing that would cause both the South and the East switches not function like we expect them to. I would still be curious what would happen if you had a resistor that's in the 450K - 470K range. 560K is still technically beyond the range of the typical 5200 potentiometer. 470K would be enough to make sure we are in range. But I'm skeptical that's the problem.

 

For your video, it looks like something is happening when you move South or East, just not very much something.

 

Getting two bad DG413DJZ from digikey seems improbable. Your V+ is reading lower than mine (you measured 4.95, I measure 5.04) but that doesn't seem significant.

 

It sure is a mystery, given that I've built two of these and tried them on two different 5200s of different vintages (one 4-port, one 2-port) and it's working for both.

 

Scott

[Swami]

Man, even my two crap-tastic CX-52's work fine with Defender, but still only up and/or left with my Masterplay clone. I just tested everything again with my thumb sticks and my Trak-Ball for Centipede, Missile Command and Millipede, so I'm disinclined to think anything is wrong with my 5200. Looking at the board schematic, is there any one thing that could be shorted or not making good enough contact that it would affect both axes this way?

 

Scott - you posted I was posting as well. I bought everything except the resistors, caps and jumper pins from Digikey. I did verify resistor values before I installed them, and measured capacitance of the little 0.1uF ceramic cap (came out to 0.0998 uF). Unless both analog switches are defective I have no idea what can be going on. Another data point: I can rub my fingers all over the bare contacts under the board and change resistance enough to trigger right and down movements, just not with a joystick or gamepad connected to the 9-pin connector. It's all very, very mysterious.

Are you seeing good resistance changes between pin 15 with 10 and 11 and +5V between pin 12 and 15 on the 5200 connector?