(Topic ID: 35328)

Vid's Guide to Bulletproofing Williams System 3-7

By vid1900

11 years ago


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#136 10 years ago

Hey Vid, thanks for the awesome guide! I am ordering parts to perform all these updates on my machine.

One quick question, you suggested removing the 27 ohm resistors and replacing them with jumper wire when replacing the TIP42 parts with MOSFETs. If I replace the 2N6122 parts on the row drive (Q47, Q49, Q51, Q53, Q55, Q57, Q59, Q61) circuit with MOSFETs (IRFZ34NPBF), can I replace the .4 ohm 3W resistor with a jumper? What about the 100 ohm 3W?

4 years later
#573 6 years ago
Quoted from Pecos:

The lower right Molex connector on my power supply was fried. Apparently, this is common on these power supplies.

I am going with the original configuration - the Molex connector soldered to the board and not the pigtail. Ed said I needed GPE parts 15-31-1026, 19-09-1029 and the 02-09-1104 contacts for this.
The bridge rectifier is 35A 400V. I will be replacing the original with GPE part number GBPC3504W, recommended to me by Ed. Thanks Ed!

Thank you for posting those part numbers. I have a System 7 PS where that connector got so hot, it unsoldered itself from the board and is missing. I was going to guess at the part numbers to order, now I don't have to!

#576 6 years ago
Quoted from johnrezz:

This board is not really fried anywhere and overall is in pretty good shape. I need to take the time to run through the entire circuit and see what is good and bad. I am finding that I am only getting 45 volts out of the HV circuit which leads me to believe some of the zeners are bad. The caps are all original and need to go, good or bad.... I have done some preliminary tests with components in the circuit but need to pull them to do accurate testing. I have to set up my bench to get started. Hopefully this weekend.
Look at the pic, mine is jumped... vs yours.
I would think that a schematic would exist for this with component values...
Are there any full on Williams Technical Manuals (TM's) available? one that shows voltage and signal path with values and test points?

I would remove that jumper and re-install the fuse holder clips to restore the GI fuse.

Page 35 of the Black Knight manual on IPDB has the schematic for the 7-9 power supply. http://mirror2.ipdb.org/files/310/Williams_1980_Black_Knight_English_Manual_with_paginated_schematics.pdf

2 weeks later
#581 6 years ago
Quoted from wxforecaster:

A friend of mine brought me a Gorgar that was resetting when both flippers were pressed. I've dealt with this issue ad nauseum on WPC89 systems, but a system 6 I have not. The power supply amazingly is all original (caps and all). While I'm fairly confident "bullet proofing" will resolve the issue, is there anything else I should look at?? Of course he brings it to me and I play 4 games without issue...

Start with reflowing the header pins on the CPU and power supply boards. Look for connections that have overheated and replace those pins and the associated connectors.

Check the large diodes on the power supply board 5V section to ensure both are working (these rarely fail).

Make sure all boards have at least 2 mounting screws and they are snugged down.

If all this fails, recap the power supply board.

#582 6 years ago
Quoted from pindel:

I've been working on a sys6 firepower board. Three lamp columns are out 2,4, & 6. All transistors and things look good so does this mean I have a bad pia(IC11) or IC10. i changed out IC13 already. is there a way to ground a pin or something on the chip to see if its bad. I don't have a probe tester.
thanks!!

Do you have a meter with a diode test? You can use that to test each of the transistors in the lamp matrix to see if the column 2,4 and 6 transistors test differently than the others.

3 weeks later
#585 6 years ago
Quoted from tomm1963:

Yeah this was a waste of time. I did most of Vids recommendations with great results. I was nervous about the above suggestion as no one on this thread has mentioned anything about it since the OP. Well I gave this a go and the result was all lights stuck ON. Ended up pulling out the IRFZ34NPBF's and going back to the original. Lucky I was careful about removal.

You must have done something wrong. I replace all my lamp matrix transistors with MOSFETS on both the rows and columns and it works flawlessly. I've even done it on system 11 games with similar results.

1 month later
#598 6 years ago
Quoted from scottmaggie:

When you swap the tip41 for IRFZ34N do you remove that sides resistors like on the tip42 side upgrade or do those remain? Thanks!

I assume you are referring to the .4 ohm, 3 watt resistors? I never remove those or the 27 ohm resistors for that matter.

2 months later
#612 6 years ago
Quoted from epeabs:

I fixed my issue. The 330K resistors I bought were incorrect. On top of that when I checked fuses, I missed the F1 which was blown. I replaced the F1 and the new diode fried again. I reinstalled the original 330K resistors, and everything works fine.

The resistors you bought were 330 ohm, not 330k ohm (330,000 ohm).

#614 6 years ago
Quoted from epeabs:

Ahhhh. Duhhhh. My bad, I obviously didn't catch that important minor detail. Thank you.

Good thing you noticed it before it was too late!

Congrats on getting it working!

#618 5 years ago
Quoted from Chisel:

Hi everyone. Great thread.
I just reworked my system 4 Flash driver board with the mosfets (IRF9Z34N) and 0ohm resistors (RCF1/4-0) from GPE. All went well and seems to be working fine (besides I do have lamp matrix issues I'll make a new thread for), but I just found some info about this on pinwiki that mentions we should also put a 1k ohm resistor on the back side between the mosfet gate and the 18v dc due to the high voltage nearing the mosfets limit?
Question: Is this 1K resistor needed or is this bad info in regards to the IRF9Z34N rated at 55 Volt, 17 Amp on GPE site?

I've NEVER installed 1K resistors on any of the Williams System 6 and 11 boards I converted. Zero failures for me. I would say it isn't needed.

I've never heard of anyone suggesting they are needed, I wonder who added that to PinWiki. Is is possible the PinWiki article mentions using different model MOSFETS?

#620 5 years ago
Quoted from MarAlb:

Read this, maybe that makes things more clear:
https://pinside.com/pinball/forum/topic/anyone-try-mosfets-in-lamp-columns-on-de
And, if you perform the MOSFET update without a voltage divider....for safety reasons it is better to use a 1K resistor in stead of a zero ohm jumper to avoid exploding 2N6427 transistors in case a MOSFET fails (which can happen). The 1k resistor won't dissipate any heat as the current to the gate is close to zero.

Interesting and makes sense. I guess I've been fortunate/lucky with the games I've updated.

#623 5 years ago

Item 2 does nothing to protect from the risk of exceeding the Vgs of the MOSFET, correct? If so, it isn't really a stand alone "option". It is a suggestion to improve the design for all options. Does leaving the original 27 ohm resistor in place provide enough protection? I like to leave them in as it keeps the stock look of the board.

I personally like option 3 - the FQP17P06 devices are about the same price as the IRF9Z34 and it doesn't require board modifications (making backing out the MOD a little easier)

#625 5 years ago

You found an elegant plan for option 4 on the DE board. The Williams boards have a different layout. I'm sure there is a way to implement option 4 on a Williams board without cutting traces and such.

2 months later
#653 5 years ago
Quoted from nerdygrrl:

Does anybody have a complete list w/part numbers for a System 7 PS rebuild kit either from DigiKey or Mouser? I can't tell if I am putting this together correctly. I want to do everything: caps, resistors, diodes, VR.

GPE is probably a better source for these parts. Some of the caps on system 3-11 power supplies are tough to come by. GPE rarely has the kits in stock these days but you can use the list of parts in the kit description to order the components separately.

https://www.greatplainselectronics.com/products.asp?cat=45

#656 5 years ago

GPE sells Richey and Nicolson in 85C and 105C

Thanks for the link to the arcadepartsandrepair.com kits. Nice to know there are options for one stop kits!

#661 5 years ago
Quoted from nerdygrrl:

Oh dang, the caps in the pic look like the ones BR used to sell. I ordered the cap kits through Arcade Repair and all of the HV rebuild stuff, etc through GPE. Pretty much split my costs 50/50 with them.

No problem, I edited your quote out of my post as well.

I use Arcadepartsandrepair.com for monitor cap kits, pots, flybacks, etc. Great stuff. I never noticed the pinball cap kits, so thanks again for the lead. The 105C Nicholson kits are more costly than the Richey caps from GPE but Nicholson 105C parts are top of the line, better than original parts.

#669 5 years ago
Quoted from nerdygrrl:

Dumb rebuild question here, after a cap kit my 5V is still hovering around 1.8. My BR tests ok, so I figured I need to swap out my VR. I ordered a 2N6059 to replace the 2N6057. How do I determine which pin is the base and which is the emitter?
I apologize for what I guess is a newb question. I just don't have a lot of experience with this style VR.

Before replacing the transistor, try loosening the mounting screws then snugging them back down. Also check where the screws come through the circuit board to make sure they not corroded and are soldered in place (on some boards they are soldered, others are not). The mounting screws are part of the circuit and need to make a solid connection.

3 months later
#761 5 years ago
Quoted from CaffeineSlug:

I'm having trouble with occasional resets on Gorgar. Pinwiki led me to check the unregulated 12V, and while I understand it can vary, I'm only getting 10V. I traced the 10V all the way back to the diodes on the power board, which are new 6A4 diodes that I installed per this guide. I'm getting 9.5 VAC on the other side of the diodes, which looks correct per the schematic.
Granted this was tested when it booted up fine. My guess is 10V is borderline ok, but it's occasionally dropping below that and causing the reset. What should I be changing or checking here if that's the case? New diodes again? Or does it sound more like I'm going down the wrong path with the reset issue?

So on one side of each diode, you are getting 9.5V AC and on the other side of the diodes, you are getting 10V DC? You should be seeing much more than 10V if both diodes are good with a 9.5AC input.

Measure DC volts between ground and each clip of F5 and tell us what you are seeing.

Remove F5 and tell us what DC voltage you see at the F5 clip (this will be the unloaded voltage).

I would look closely at the pins in J1 for loose, tarnished, worn out connections. Does J1 show any signs of getting warm (yellowed or burned housing)?

#763 5 years ago
Quoted from CaffeineSlug:

I first checked at the MPU and that's where I saw 10V, at TP1. Then checked at the MPU connector, then power supply connector, fuse, capacitor, and diodes. Same everywhere.

I'm getting 10.0 VDC at each clip with F5 in, and 13.1 VDC with F5 removed.

Pins 3 and 6 on the board look pretty toasty, but the connector shows no signs. (I don't understand 6 looking bad, there's no mating pin for it in the connector?)

6 Being toasty might have been caused by the board being from another game that uses pin 6. Pin 3 is for flipper power so I can't see that as the cause of your issue. I would order a replacement wafer connector and pins from GPE and replace them when you get a chance.

Look below the power board, there are several fuses mounted on the backbox. There is a pair of 4A SB fuses there labeled F2 and F3. These fuse the power supply as it enters the power supply board. Using your meter on AC, measure from ground to each side of these fuses in these fuse holder as well as the inputs to the diodes on the power supply board. You are looking for a voltage drop caused by a dirty connection somewhere. After you measure, remove these fuses, clean with a green scrubby or something, reinstall and remeasure to see if things improved.

#767 5 years ago
Quoted from CaffeineSlug:

Before:
10.0 to 9.5 VAC, and 9.7 to 9.6 VAC
Didn't do a great job of cleaning those fuse clips with the big cap in the way, but I looked at the fuse for the one with the 0.5V drop, and it was measuring about 5 Ohms resistance. It was also a 1/4A fuse! I replaced that with a 2.5A SB fuse (don't have any 4A on hand).
After:
9.9 to 9.8 VAC, and 9.8 to 9.8 VAC
Diodes both measured 9.8 VAC going in and 11.1 VDC coming out.
MPU TP1 is now getting 11.0 VDC, so definitely an improvement over where I started. Anything else I should be looking at? If not I'll just keep an eye on it and see if I get any more resets.

Nice find!

Looking at the reset circuit, I can't see how a voltage over 7ish volts on the 12v circuit would cause resets. Since 5v is derived from the same source as the unregulated 12v, I would play it for a while and see how things go.

8 months later
#793 4 years ago
Quoted from wolffcub:

When changing out the old tip42 to the irf9z34npbf units is there issues with running leds? I made the switch yesterday and now some groups of playfield lights stay on flickering.

I’ve never noticed a change in ghosting after the mosfet upgrade.

6 months later
#834 4 years ago
Quoted from Beatnik-Filmstar:

Not asking if I should replace it - more "should I put it back in place after replacing the other caps" since I'm seeing so many pictures of these sound boards without it even being present.

Yes you should, expecially since it is listed on the schematic for your board.

Quoted from gdonovan:

Interesting Blackout problem or two;
When the machine is on and you play a game, finish.
1) Game will speak when game over but usually gibberish. Blackout Mission Green for example. Usually 3 words strung together at random. This has been answered and is normal for the title and in the manual, doh!
2) If the game is sitting with game over and you just played a one player game. Player one display will display your score and alternate with high score. Other three displays will have 000,000. So far normal.
Game will time out to attract mode "BLACKOUT" flash the lights and displays and when the lights and display come back all the displays will show high score. None will resort back to 000,000 and only the one player will alternate with high score and last score.
Curious. Where do I start looking?
Also had one time when playing the red-green-yellow-blackout inserts would not reset after hitting the outhole and was able to trigger it over and over.
Almost sounds like a bad ram chip or voltage issues. The game does get angry when the garage furnace kicks in which is unusual as it is plugged into a very stout commercial grade surge protection device from a very large copier!

You should always replace the 40 pin unless you know it is new. At least wait to troubleshoot weird behavior until you have replaced it. Including your game's feelings about your furnace.

You will have better luck getting answers to your specific Blackout questions in the club thread. https://pinside.com/pinball/forum/topic/blackout-club-fans-welcome

#836 4 years ago
Quoted from Beatnik-Filmstar:

Rottendog long since installed. No 40 pin to worry about.
(I’m not the Blackout person)

oops, sorry about that! Combined the two questions and answers. Fixed my post.

1 week later
#843 4 years ago
Quoted from gdonovan:

Question and pardon my ignorance of Williams System 6 but I'm learning fast.
If one of these diodes has failed will you see a low 12 volt line to the MPU? Say in the neighborhood of 9.3 to 9.6 volts DC?
Because that is what I'm seeing coming out of the power board 12 volt unregulated line, roughly 9.6 volts.
Edit. Just took a meter to diodes, yup one on the right is open. Answered my own question I reckon.

Yep, if one of the diodes failed, the voltage would be low. It will also quickly stress out the large filter cap as it tries to even out the pulsing voltage.

#846 4 years ago
Quoted from gdonovan:

Just a follow up on this point about the workshop furnace, nothing done on the machine changed the behavior but I got a volt meter out and when the furnace blower kicks in the outlet voltage is dropping from 117 to 97! I'm surprised other machines have not exhibited issues as well with that kind of drop.

Wow, that's quite a drop and a good find. feels like you have a wiring problem with that circuit or it is very loaded.

1 month later
#880 3 years ago
Quoted from Armyaviation:

This game looks like it was on a location back in the 80s and then pulled and has been sitting for 20-30 years. The rubbers were original, the pf has no wear at all. It was too good to pass up for $100 since I have never owned a widebody. Someone correct me if I am wrong but I think my stellar wars Has a system 6 mpu??? There doesn’t appear to be any work done on the board and no corrosion from the batteries. I don’t think this battery pack was stock?[quoted image][quoted image]

Looks like a stock battery holder to me. Look carefully at the chip just above the battery holder. Hard to tell for sure in the pictures but there looks to be some battery damage there.

Check the numbers on the paper stickers on the driver board, CPU board and the sound board. If they match, there is a good chance they are original to the game. One thing for sure, that driver board doesn't have that many hours on it, the resistors would be burned like so many other games of this era. Also, the metal can on the CPU crystal isn't all banged up so it hasn't been out of the game very much.

1 week later
#898 3 years ago
Quoted from Armyaviation:

So I spoke too soon, I checked the 5v at the psu and sometimes it reads 3.5 and sometimes 4.1 now. Not sure why the fluctuation. I checked the cap per PinWiki and it said it was fine. Regardless when I check the pins and say they are 4v, I checked the same wires at the mpu and they are almost nothing. I checked the same 4v with the molex connector attached by touching the metal through the opening and it’s like .5v. Could that voltage drop when the connector is plugged in or is my future full of new connectors and pins...

Have you re-flowed the solder or better yet, replaced the header pins on all your boards?

For the 5V - loosen and tighten back down, the mounting screws on the 5V regulator on the large heat sink. The screws are part of the circuit and get oxidized and make a bad connection.

1 month later
#908 3 years ago
Quoted from Armyaviation:

Ok I found my first issue and fixed it, weak solder joint on the 12v on power supply. I fixed that and now TP1 on mpu has 12v and 9 has 5v as required. The top led cane on on the mpu.
I took the driver board off and soldered on a new 40 pin plug and touched up solder on male side. Reconnected and now both leds come on with nothing on score displays. I don’t have any batteries in yet

Did you replace both sides of the 40 pin? Leaving the old, round pins on the male side isn't good.

You need to reflow solder or replace each and every header pin on every board.

When you have the game on and there is nothing on the score displays, look at different angles into the displays to see if there is any orange glow at all. If not, CAREFULLY measure the high voltage supplies to the displays.

#910 3 years ago
Quoted from Armyaviation:

So before I changed to 40 pin, I would only have the top led, if I cycled the power switch fast, the displays did come one for a bit then off, and the led changed to the bottom one. Now both leds come on. I did reflow solder on all of the male pins

Both LEDs on indicated a CMOS failure. But until you replace the male pins of the 40 pin, you are chasing a ghost.

2 months later
#931 3 years ago
Quoted from gdonovan:

No need to hack the wiring, you simply move the wire from the bridge to the fuse and add a short jumper wire from the fuse to bridge.
IMHO this is a mandatory upgrade as detailed by Williams and should never be undone, machines were catching fire. All machines made after a certain point came with the "upgrade" from the factory.
I say "upgrade" as it should have been on the machine day one.

Where did you see that Williams suggested this mod? I can't find any evidence they suggested it. On top of that, they didn't add a fuse in front of bridges until all the bridges were moved onto power boards, sometime in the middle of the system 11 era in the late 80s. Early sys 11 still had no fuses on the offboard bridges.

Not saying it isn't a mandatory upgrade, it is for sure especially considering the low cost and high protection it provides.

3 weeks later
#938 3 years ago

Fuse clips: https://www.greatplainselectronics.com/proddetail.asp?prod=1A1907-03
Bridge Rectifier: https://www.greatplainselectronics.com/proddetail.asp?prod=GBPC3504L
.156 (3.96mm) pitch header pins (cut to size): https://www.greatplainselectronics.com/proddetail.asp?prod=26-48-1245

I don't really like the look of the cut to size header pins so I order specific size KK Series connectors from Mouser but that is much more expensive and no better (only cosmetic).

5 months later
#961 3 years ago

Here are the voltage based test points on the CPU board. Meter on DC. Black lead on ground. Red on the 5V or 12V test point.

System 6 CPU1 (resized).jpgSystem 6 CPU1 (resized).jpg
11 months later
#986 2 years ago
Quoted from Mr_Outlane:

** I use the audio/visual auto alerts mostly.

Love it!

6 months later
#1032 1 year ago
Quoted from Magadovski:

vid1900
Ok found the problem and fix it, it was the 39R 2w flame proof resistors i put in,
Put the old back and the fuse dont blow.
But my displays are dead, what have i messed up? Thankful for some guide and help.[quoted image]

Those are supposed to be 39,000 (39K) resistors, not 39 ohm that it looks like you installed.

Carefully measure the display voltages that the board is putting out. It should be close to -100 and +100.

You may have overloaded the zener diodes in the display power supply but I would think the fuse would have blown before much damage was done (assuming a 0.25a fuse was installed).

Q2 might be toast but measuring the output voltage should tell us more

#1035 1 year ago
Quoted from Magadovski:

Messured between ground and f1 fuse now and got 93-94 v
Q2 seems ok

The fuse clip and cap voltages are before the regulator circuit and not what we need.

Measure from the voltages on J5 at the top left of the board. Pin numbers are counted from left to right when installed in the game. Be VERY careful not to touch multiple pins together when measuring or you will damage other parts of the board or at the very least blow some fuses. You are dealing with voltages that can kill you so be careful.

Between Pin 3 and ground should be -100V DC
Between pin 4 and ground should be +100V DC

#1037 1 year ago
Quoted from Magadovski:

Ok i got no reading at all between does pins

OK, make sure the fuse is still good. If it is, we need to dig into the regular circuit some more. Please create a new thread and link it here so we can talk there and not derail the Bullet Proofing Thread any more.

1 month later
#1044 1 year ago
Quoted from SMP14:

Hi there, I have a Williams time warp head with all the wire harnesses for the backbox. How hard would it be to upgrade the wire harness to a system 7 to make, oh idk a warlok or something. Any documentation on what the difference/conversion is? Thanks

System 7 uses ribbon cables between the display boards and the driver board so that’s easy to make work. The display driver board mounts on the back of the backboard and you mount another regular display for the ball in play and credit display. Should be pretty easy to make work.

2 months later
#1077 1 year ago
Quoted from zug1619:

While I wait for the Bridge Board to get here, I noticed the J1 connector has a wire pulled out of it. The bottom right one. I am assuming that the gray w/white stripe wire is a ground...as it's been connected to the screw hole.
Can anyone confirm? Or maybe I'm wrong?
I can tell it's a female connector...but not sure on size? Marco has .93 and .62...is it one of these? They also have .156, but that looks like a different style.
Lastly, is there an easy tool to remove the old terminal? was just gonna pull with needle nose or maybe a paper clip.
Dan the Painter
[quoted image][quoted image]

They are 0.93 molex connectors. You need the socket side (pin side is on the board). They are pretty tough to get out of the housing without the proper tool.

2D202C77-E506-4ED6-A404-12FFE8FE2ABA (resized).jpeg2D202C77-E506-4ED6-A404-12FFE8FE2ABA (resized).jpeg
#1085 1 year ago
Quoted from zug1619:

Schwaggs, the molex remover tool came and it made the job super easy...I did stab my-self in the finger but got the connector out without damaging the housing!
Re-crimping the CT and adding back to the housing was super easy too.
Many thanks!

Awesome! A textbook example of the right tool making the job easy!

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