416 replies to this topic

[zebulon]

Have you got a dmd connected Kris? The voltages will range well over the high side if there's no load.

[antropus]

Thanks Zeb.
You know, before I went to sleep yesterday I did install the pinDMD2 and the custom vpinmame DLL file. I plugged the ribbon/bridge between the boards and loaded one of the ROMs. Nothing happened with the DMD. I thought it was weird that nothing showed up, so I measured the loads on the back of the DMD. 62v, 12v and 5v were all correct (both 80v transformer and PSU working fine), but both 125v and 113v were reading zero (meaning the 100v transformer was in trouble). I turned everything off and checked the 100v transformer just to find out that the 1A fuse was busted. I added a new fuse, turned everything on again and blew once again. When the piggy is by itself, I can read from all terminals as I mentioned before, but as soon as the pinDMD tries to send a signal to the DMD, the fuse on the 100v transformer blows. This little transformer is rated 100W and although this should be more than enough, maybe the initial load is being too much for the little transformer to handle? Maybe I need bigger wattage to run it without blowing the fuse? I'm thinking about getting a better transformer, rated 200W, (2A).

A shame that I'll spend another 30 bucks just to test it instead of buying one of those combo transformers you guys are about to order (which are probably a much better/reliable solution than my two weak transformers anyway ). But I'm here as the sacrificial lamb anyway, the official guinea pig of this experiment

On top of that, I'm still afraid the 80v transformer will be the next to blow a fuse once the display is powered, since it's rated 80v at only 0.02A (20mA). Sorry for my ignorance, but is this only 1.6 Watt?

Thoughts?

-Kris

[russdx]

sounds like you need a bigger fuse not transformer?

[MTPPC]

Try a slo-blo fuse.

[antropus]

I'll try using some slow blow fuses. Thanks guys.

-Kris

[antropus]

No... no go.
 
I got some slo-blo 1A and 2A fuses on my way home. Got here, put the 1A on and turned the whole thing on, including the pinDMD2 all connected.
Measured the loads and again, the 62v, 12v and 5v all read correct and stable, but now instead of too high, the readings on the 100v were too weak: around 28.6v on the 113v and 29.7v on the 125v. So, I thought it was the 100v transformer since the fuses were installed in it and I thought the slo-blo happened partially, so I was still getting some current and I think I was right, because right after the restart the slo-blo fuse finally broke.
I thought "what the heck! I'll put a 2A fuse this time around". Tried and everything looked ok until I measured the loads again, that now read 0v on both 100's... turns out that the 2A fuse kept the Japanese transform alive, sending the problem all the way up to the DMDpiggy, breaking the 500mA fuse of the 100v circuit.
 
So, yeah, tricky. When the fuse doesn't break on the source it breaks on the piggy. Seems to me that this lilttle transformer is pretty shaddy and the source of all trouble so far. I ordered another one with double the Wattage, 200W max load, 2A. I should get it tomorrow or after. To my surprise, the custom little 80v transformer is still going strong and the load is reading constant 62.9 now, which is great! Touching the enclosure it doesn't even feel warm. I hope it stays this way when the plasma is finally working, if it works at all
 
RoccoC, I think a 2-1 solution for that price is really the way to go, as long as the output is close to the numbers we expect. I would be interested ordering one as well.
I still want to test the new transformer this week though, just to make sure.
 
Cheers,
-Kris

Edited by antropus, 26 March 2013 - 05:02 AM.

[RoccoC]

Kris, first off, congrats on the second child! Exciting!

 

Thanks for digging up the DMD voltage info in your previous post. Also interesting to find out that the DMD Piggy is fused at 500mA...that would lead me to believe that your 100V/100W transformer would be more than enough to power it. Weird. Hopefully you see better results with the 200W model.

 

Depending on your results, I may just suck it up and spend the $125 or whatever on a single prototype transformer to confirm that it works before committing to a larger order.

[zebulon]

I'm thinking the issue is inrush current.....

 

From Wikipedia...that great bastion of everything true...(yeah right)

 

"When a transformer is first energized, a transient current up to 10 to 50 times larger than the rated transformer current can flow for several cycles. Toroidal transformers, using less copper for the same power handling, can have up to 60 times inrush to running current. Worst case inrush happens when the primary winding is connected at an instant around the zero-crossing of the primary voltage, (which for a pure inductance would be the current maximum in the AC cycle) and if the polarity of the voltage half cycle has the same polarity as the remnance in the iron core has. (The magnetic remanance was leaved high from a preceding half cycle). Unless the windings and core are sized to normally never exceed 50% of saturation, (and in an efficient transformer they never are, such a construction would be overly heavy and inefficient) then during such a start up the core will be saturated. This can also be expressed as the remnant magnetism in normal operation is nearly as high as the saturation magnetism at the "knee" of the hysteresis loop. Once the core saturates however, the winding inductance appears greatly reduced, and only the resistance of the primary side windings and the impedance of the power line are limiting the current. As saturation occurs for part half cycles only, harmonic rich waveforms can be generated, and can cause problems to other equipment. For large transformers with low winding resistance and high inductance, these inrush currents can last for several seconds until the transient has died away (decay time proportional to ~XL/R)and the regular AC equilibrium is established. To avoid magnetic inrush, only for transformers with an air gap in the core, the inductive load needs to be synchronously connected near a supply voltage peak, in contrast with the zero voltage switching which is desirable to minimize sharp edged current transients with resistive loads such as high power heaters. But for toroidal transformers only an premagnetising procedure before switching on allows to start those transformers without any inrush current peak. See at: http://de.wikipedia....torschaltrelais, or http://de.wikipedia...._Transformators"

 

 

I'd throw a thermistor on the input and see if that made a difference.

[jat428]

This is another option for the 100v transformer, only 15$ more but with free shipping is really only 6$ more

http://www.amazon.co...own transformer

 

Would be nicer to only have one transformer though

[PinKitty]

Hey Kris (aka antropus),

The 100V transformer that I am using comes from Suzo Happ, Part Number 80-2000-00.  They runcost about $18.  As far as fusing, I did not do any.  I used the William/Bally Dot Matrix power driver board that already had the fuses in them.  I figured if those fuses didn't like my configuration, they would let me know.  As far as the amperage on this particular transformer, it is only 1 amp.  My 80V transformer looks very similar to my 100V transformer. 

 

This is a post I put in another forum back in July about how I did the two transformer hookup:

 

I've used a Bally Williams dot matrix controller board to power my plasma dmd with russdx pinDMD board. To put power to the dot matrix controller board, you need to get your 5V and 12V and ground from your computer supply. Then two small step down transformers to run the 80VAC and 100VAC that would normally come from the large transformer in the bottom of a real pinball machine's cabinet. In the US, I use a 120VAC to 100VAC Japanese step down. These are relatively inexpensive and easy to find on internet. Here's one source
http://www.voltage-c....ansformer.html

For the 120VAC to 80VAC, I found it here..http://edcorusa.com/c/37/xpwrseries. When you go to this site, you need to select your secondary voltage on the left st 80V. Then the transformer will come up at $20.01.

The wiring diagram for the dot matrix control board is found in wpc games manuals. For instance, you can go to the international pinball database and look up Theatre of Magic. The diagram is on page 3-31 of the English Manual.

I have not used the exact tranformers from these websites to power my display. I was fortunate enough to come across some at work. But I hooked up this system, and powered my Vishay plasma display this way, so I know the concept works. I used russdx pinDMD board to run the signal from visual pinball. However, I found my Cherry displays do not work with the pinDMD board. Russdx is still working on that.

 

So I can tell you this method does work.

 

Regards, PinKitty

 

 

[antropus]

RoccoC,
thank you so much! Yeah, exciting times

Zeb,
worth trying, but not sure exactly where I should install it. Between the transformer and the piggy?

jat428,
thanks for the link. I thought the 500W would be overkill and I bought the 200W version, similar to that one.

PinKitty,
thanks for the info. Here is an upgrade on the whole soap opera:

I did get the new 200W 120V to 100V step down transformer and this one is pretty steady and didn't burn a fuse once. Without connecting the 14-pin cable from the pinDMD2 the output from the piggy reads all voltages without a problem (other than reading the 113v at around 105v and 125v close to 140v right now, but based on what Zeb said, this would be expected if the pinDMD is not connected anyway). The 5v, 12v and 62v never gave me any trouble and they all look beautiful.

BUT... every time I connect the piggy AND the pinDMD2 to the display and turn on the whole thing, the 100v section of the piggy ALWAYS blows the fuse... INSTANTLY!
I thought it could be the order I was turning on things (I know... doesn't make a lot of sense, but I'm going by elimination, literally ), so I got a bunch of fuses and tried: 1) turning on everything at same time, 2) turning only the pinDMD2, waiting for windows to startup and then turning the piggy on, 3) turning on the computer and the transformers until windows is loaded and then connecting the pinDMD2... no matter what I do, as soon as the piggy and the pinDMD2 are connected to the display TOGETHER, the fuse will blow instantly.

The thing is, now I know for a fact that:

1) the transformers are feeding the right voltages to the piggy, other than a few volts difference, but way under the tolerances
2) without connecting the pinDMD2, the straight connection between the tranformers+PSU and the piggy is making the piggy output all voltages in the correct pins, but the 113v is reading 105v and the 125v is reading almost 140v
3) I just eliminated the possibility that the display was busted by plugging it to my Monster Bash. It looks bright and beautiful in there! The voltages are reading somehow low in the real pinball, with the 113v reading only about 93v and the 125v reading about 106v, 13v difference, not 12v as someone mentioned that was A MUST in another forum.
4) the only two components that can be causing the problem as far as I can tell are the piggy itself (highly probable at this point...) or the pinDMD2.

Since PinKitty managed to run his plasma display with an original Williams/Bally DMD power board, that makes me think that this board might have something that is missing in the piggy, like some component of better quality to ease the loads or maybe the piggy itself is busted, since the readings on the output are so high (close to 140v on the 125v now, when the tolerance would be 112.5v - 137.5v... although my real pinball only reads 106v)

I'm really curious to try a different DMD power board. One that could generate the voltages without blowing.

So, that's what I have for now.

Suggestions more than welcome, as usual.

Thank you so much for baring with me guys. The team effort e greatly appreciated.

-Kris

ps.: one last test would be plugging the piggy to my real pinball and seeing if it works there, but now I'm afraid something else can happen and I REALLY don't want to get my MB involved in this mess

Edited by antropus, 29 March 2013 - 07:16 AM.

[antropus]

Just for reference, here's a kit to repair an original WPC95 power board. Anything you guys see in here that could be present on the piggy so it doesn't blow?
http://www.greatplai...d=WPC95-HVP-KIT

-Kris

[antropus]

This board has some good reviews in some websites. It's the whole board, not only the HV session, reason why it's more than double the price (about 89.00 at mad-amusements) and the voltages generated are also slightly different, but seems like a safer bet. Or not?
http://rottendog.us/DMD089.html

-Kris

Edited by antropus, 29 March 2013 - 10:08 AM.

[antropus]

Another alternative, expensive and it comes from Australia, so extra expenses, but seems like well made: http://www.homepin.com/wms.html

[zebulon]

Well, I can say that the homepin board will be a better quality board and it is an exact duplication of the Williams design. The odds are good that it would work without a hitch.

 

As for the thermistor location, it's use is to slow the initial saturation of the transformer and thereby reduce the spike of current so in this case I'd put it inline on one of the ac leads going into the transformer.

[RoccoC]

I decided to order a sample of the 80V/100V 1A transformer and should have it Monday. I received the Vishay display and DMD Piggy last week, so I'll be able to hook everything up and compare the piggy output voltages with those that Kris is seeing. Unfortunately I don't have a pinDMD2 yet - I placed an order with VirtuaPin last week, but not sure if their stock is already accounted for - so I won't be able to actually test the display, but this may be able to tell us if Kris's piggy is bad.

Edited by RoccoC, 29 March 2013 - 06:57 PM.

[antropus]

Thanks again Zeb. You know, that board really does look well made, but I haven't heard of anyone who actually bought and used it. The Rottendog on the other hand has plenty of comments in different forums and the overall consensus is that it really does work well. It's much bigger than the piggy, but it is cheaper than the homepin and I found it locally, at Bay Area Amusements. I ordered it for 89 bucks and if it doesn't work maybe I can use it as a backup in case my pinball fails one day. I should get it in 2 days or so.

 

RoccoC,
awesome to see someone else trying it out! I thought mameman ordered the parts and was ready to test it by now as well. It will be great to compare the boards and try to track down what's happening.

For now, here's my detective work of the night: compare the piggy's voltages to a real pinball's DMD power board. Here you go:

J606: Low Voltages 5VDC, 12VDC and GND)   

Piggy                          Pinball DMD Power Board
                                                         
 Pin                 Voltage                              Pin                  Voltage
  1                    GND                                   1                      GND
  2                    UNUSED                           2                      UNUSED
  3                    GND                                   3                      GND
  4                    5VDC                                 4                       5.1VDC
  5                    5VDC                                 5                       5.1VDC
  6                  12VDC                                 6                     11.9VDC
  7                  12VDC                                 7                     11.9VDC

Result: virtually THE SAME
Conclusion: the loads being fed to the piggy are perfect and on the dot, so no problem detected here.

Edited by antropus, 30 March 2013 - 07:42 PM.

[antropus]

J605: High Voltages (80VAC and 100VAC)   

Piggy                      Pinball DMD Power Board
Pin                 Voltage                       Pin                Voltage             Expected Voltage
1 + 2      =      83.8VAC                  1 + 2      =      85.5VAC                      80VAC
3 + 5      =    102.6VAC                  3 + 5      =    105.9VAC                    100VAC

   4                 UNUSED                   4                 UNUSED
 

Result: the loads coming from the transformers are actually closer to the expected loads on the piggy than on the actual pinball.
Conclusion: I don't see the problem being on the transformers side, since the correct voltages are being generated to feed the piggy.

Edited by antropus, 30 March 2013 - 07:43 PM.

[antropus]

J604: Voltages generated by the Piggy/DMD Power Board

Piggy                     Pinball DMD Power Board
Pin                 Voltage                       Pin          Voltage
1                  140VDC                        1            116.6VDC
2                  105.6VDC                     2           104.6VDC
3                  UNUSED                      3            UNUSED

4                  GND                              4               GND

5                  GND                              5               GND

6                 5.1VDC                          6              5.1VDC
7                11.5VDC                         7            11.5VDC
8                62.7VDC                         8             62VDC

Result:pins 2 to 8 are virtually THE SAME.
Conclusion: the session of the piggy responsible for producing the 125VDC looks BUSTED, since the piggy is producing a much higher voltage than it should. Based on the load on pin 2 (105.6VDC), the expected 12V offset on pin 1 would produce a voltage of 117.6VDC, not an absurd 140VDC! Although Zeb mentioned that the load should read much higher than expected when the 14pin DMD interface cable is disconnected, in the real pinball it was proved that the difference is minimum when turning on the machine with the 14pin interface connected or disconnected. When the 14pin cable is disconnected, the DMD power board register loads of 116.6VDC and 104.6VDC, exact 12V offset between the expected 125VDC and 113VDC. When the 14pin cable is connected, the loads read as 117.3VDC and 105.4VDC, still virtually 12V offset, but only 1VDC more than when the cable was disconnected. So, yeah, the 140VDC is pretty extreme here.

Edited by antropus, 30 March 2013 - 07:44 PM.

[antropus]

Another detail I noticed on the real pinball: the J605 has 11 pins, not only 4. I believe it's like this because there are other things being fed to the board, that's not only a DMD power board after all. But what's curious is that there's a common ground used by the high voltages there. I can use the multimeter to verify that selecting pin 1+GND will give me roughly half of the 85.5VAC and pin2+GND will give me the other half. That doesn't happen on the piggy, because the ground being used doesn't come from the transformers, but from the little 2pin (no ground) PSU instead. Do you think this could be a problem as well? I mean, shouldn't I be able to read half of the load from the exact same pins on the piggy and for that I would need a common ground for the high voltages? I never connected the ground wire to the 80V transformer for example, since the 100V is only 2 pin anyway. Should I?

Edited by antropus, 30 March 2013 - 07:19 AM.