I just ripped apart a FirePower with the exact same mod. GI running to a third BR...had no clue what they were trying to accomplish. Thanks to barakandl for clearing this up a year ago!

Humblebragging here but having a solder vacuum like the Hakko FR-300 is like doing this on easy mode.

This took 15 minutes:

IMG_20180116_203948 (resized).jpg

And having a good iron, this took 15 minutes:

IMG_20180116_210704 (resized).jpg

I just got a 300. The price gave me some heartburn but there is no substitute for having the right tool for three job. It's amazing.

got a question about a globetrotter. I purchased the replacement MPU board (mine was missing.) When I turn it on after a couple of days, it seems to start up correctly. I get a click from the solenoid board around the 4th flash of the MPU board, then I get a second click a couple seconds later when the MPU LED gets to the 6th flash.

What is wierd is that after a couple of minutes, when power cycling, the first click happens and then everything stops - the MPU LED is solid on with just 4 flashes. I don't get any more flashes or a second click. I'm not sure what is clicking or if that is a symptom or the problem. Does anyone know what to check? I have replaced the C23 but thats all so far.
Mark

Im working on a data east torpedo alley cpu, im replacing one tip122, i want to replace all of them. I assume this is a bad idea, any opinion on this type of shotgun approach vid?

hah! I am pretty sure its the person behind the tool that is 90% of it, you probably would do a great job with a simple iron and sucker. The last time I tried to use a soldering gun I destroyed the board I tried to take a connector off, had to buy a replacement.

The hakko is amazing. Expensive, but amazing.

I have a Gorgar that has a new Kohut MPU board. The diver board,sound board, and power supply are all original but reworked The game plays fine, but on some occasions - seems to be random and not very often - the game will freeze with loss of all solenoids and the displays go blank. Eventually the displays come back on to display attract mode scores, but the playfield lights, etc. don't go into attract mode. If I switch the machine off and back everything resets back to normal.

I am wondering if this is a power issue and if there is something from Vid's original post and the responses from other pinsiders that might address this issue.

Just wanted to say thanks for putting this guide together, picked up my first SS pinball last week (Gorgar) and followed the steps outlined by Vid to bulletproof it.

I just rebuilt my power supply in my System 11C Rollergames. I bought the capacitor kit from Great Plains Electronics. Great Plains didn't have the high voltage kit in stock so I bought the parts for the high voltage rebuild individually on Great Plains. They did not have the 91V zener diodes or the 1/2watt 330K resistors in stock, but I was able to source the 91V zener diodes and the 1/2watt 330K resisters locally. I reinstalled the power supply board and plugged the machine back in. When I turned it on, I heard a "sizzle" and saw some smoke from the board and immediately shut it off. The R6 resistor which I purchased locally fried. I don't think I installed it backwards from looking at my before picture. I removed the resistor and installed a new one. When I turn the machine on there is no smoke and the resistor has not fried, but my displays do not work. I had done the 91V mod to dim the display, so I removed those diodes and replaced with new 100V diodes but the displays still do not work. All fuses are good. When the R6 fried, did I kill my display?

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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).

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!

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?

Another question: Does anyone have any nice clear sys4 mpu and driver board component layout images and schematics? IPDB has this but the fine print is not legible for me.

Last question: I've been soldering for a long time, I only recently moved to lead free solder when my normal leaded solder ran out. Old school roots demand solder joints to be shiny, otherwise it's a cold joint. With the new lead free solder, nearly every joint looks like a cold joint to me. Is this normal for lead-free?

Thanks all!

Check the schematics for 'Phoenix'. I recall them having a very good scan

Oh my, that's much better! Thank you!

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?

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.

Thanks MarAlb. So on a Williams system 4 game, I should replace my 0ohm with 1k, put the second on the backside as described and just totally remove and leave empty the 2.2k spots?

Can I use 1.2K in place of 1K (I happen to have a bunch of 1.2K)?

There are a few options here and everyone is free to choose the one he or she feels the most comfortable with....

1) leave it like it is as at the Williams boards the FET's run just below their critical limits

2) replace the zero ohm jumpers by 820 ~ 1200 Ohm resistors to avoid big problems in case a FET fails

3) Use FQP 17P06 FET's with a bigger 25V Vsg range. Again, you have the choice to use zero Ohm resistors or a 820 ~ 1200 Ohm series resistor

4) Install a voltage divider. At system 3-7 driverboards you need to remove the 8 2k2 resistors and add a resistor between Source (18V) and Gate at the backside of the board. In case of system 3-7 driverboards I would use a 1k2 resistor between Gate and Source and a 820 Ohm or 1k resistor in stead of the 27 Ohm resistor previously used for the TIP transistors.

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)

Option 2 does nothing to limit the Vgs to the FET. It just limits the current in case a FET fails by whatever reason. It will save the 2N6427 darlington transistors and maybe more. 27 Ohms is still too low. It is not very critical but I would stay in a 470 to 1500 Ohm range.

Option 3 provides some more headroom, I would still use a resistor like mentioned in option 2, just to protect the electronics in case of a failure.

Option 4 is technically a nice solution, but requires a some more work and skills. It is still reversable if you would get rid of it in the future.

Option 1 is for me a No-Go

I prefer option 3 or 4 ( or remain the Original TIP transisitors ). For Data East games I prefer only option 4.

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.

Here is this info from PinWiki on the use of MOSFETS:

6.19.2.1 Reducing heat by replacing the TIP-42 lamp drive transistors and eliminating the 27 ohm current limiting resistors

The original Williams (and Data East) lamp matrix circuitry dissipates a lot of heat through the 27 ohm current limiting resistors. Often, this part of the circuit board is badly heat damaged. Using modern MOSFETs (IRF9530, IRF9Z34N or FQP17P06), the heat (and power consumption) can be reduced substantially.

Once MOSFETs are substituted for the TIPs in the lamp driver circuit, it is possible to replace the 27 ohm resistors with simple jumpers or even leave the 27 ohm resistors in place if they are in good shape as the low resistance will have a negligible effect on the operation of the MOSFET. However, the problem with either of these is that the MOSFETs are driven by 18 VDC Source to Gate voltage which is dangerously close to the absolute maximum rating of the IRF9530 and IRF9Z34 of 20 VDC (this also holds true for Data East MPUs). The FQP17P06 has a higher Vgs rating (25VDC) than either the IRF9530 or IRF9Z34N - but you are still driving the part at over 70% of its absolute maximum. Typical uses for these MOSFETs drive them by about 10 VDC Source to Gate voltage (or -10V for P-Channel MOSFET's used here).

By using a "Voltage Divider" circuit with two 1K, 1/4 watt resistors to divide the source 18 VDC in half, the MOSFET will be driven with 9 VDC Vgs.
1K resistors installed on the component side of the board.
1K resistors installed on the solder side of the board.

Parts Required

8 P-Channel MOSFETs (IRF9530, IRF9Z34N or FQP17P06)
16 1K Ohm 1/4 Watt resistors

Procedure

Remove the TIP-42 transistors Q63, Q65, Q67, Q69, Q71, Q73, Q75, Q77
Remove the 27 Ohm resistors R149-R156
Remove the 2.2K ohm resistors R141-R148
In place of the 27 Ohm resistors, install 1K Ohm resistors
In place of the TIP 42 transistors, install the P-Channel MOSFETs, oriented the same as the TIP-42s were oriented
On the solder side of the board, install eight 1K Ohm resistors between the MOSFET gate and the 18VDC source.

349px-WMS_Sys3-7_Lamp_FETs_Back (resized).jpg
399px-WMS_Sys3-7_Lamp_FETs_Front (resized).jpg
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Our group bought a Data East Star Trek, in "working" condition. Game was in such bad shape, had numerous locked on transistors in the light matrix causing these hot spots. The resistors were getting so hot from the locked on transistors, that it was melting the solder.

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I had a Laser Ball that locked on when I first powered it up. I didn't know about the issues like this at the time, so I left it on while checking voltages, a bit later I heard a 'plunk!' as two of the resistors fell out of the board and landed on the bottom of the head

That's one way to desolder, I suppose.

Just to show another way to install the extra resistors. It requires to drill holes in front of the Source pins from the MOSFETs. If you do it like this, you will drill exactly into the 18V trace at the bottomside in which you can solder the resistor.

mosfet_2 (resized).jpg

Richard;
It’s not the driver itself, it’s actually the big pill resistors that burn up. The TIP122/102/120 darlington originally used takes a fair amount of wattage to drive it. So the resistors overheat badly.

Going to the mosfet will be more efficient and it eliminates the wattage going through the resistors. Makes a big difference. I don’t have the data with me, I’m on the way to MGC, but it was a very meaaureable reduction in total machine wattage and backbox temperature.

I did the mosfet swap almost 10 years ago on my black knight and haven’t had a single failure on the driver board since then. And all I swapped was the mosfet, no resistor changes.

When I was doing board repair work, nearly every board that came in had damage due to those resistors. In extreme cases I’ve even seen them desolder themselves, or the heat cause damage to the switch matrix components directly above them.

-Hans

Ahhh, gotcha. The resistors are like the GI on system 7. Even on a good game, they’re running hot and look fried. Only once have I seen a board where the paint hadnt flaked off them yet, that driver looked pristine, likely never even installed in a game.

I'm working on a system 6 firepower. The two fused GI's seen in picture are really high. Does this mean a bad transformer or can something else cause this?
Thanks!

afpgi (resized).jpg

How did you measure the voltage?
Black lead to ground and the red lead at these points?
This is the wroung way.

Put one lead at the left point and the other on the right point.
Be sure to set the DMM to AC voltage.
Then you will see a different voltage.

Peter

On my Blackout machine I split the GI over 4 strings.
One for the playfield, two for the back box and one for the cabinet.
On the back of the back box insert I could split the strings to 18 or 19 lamps each, thus creating 2 strings of 5 Amp.
The playfield was to complicated to split, so I kept it as 1 string, but fused it at 10 Amp.
The cabinet only has 2 or 3 lamps at the coin door, so this is a 1 or 2 Amp. fuse.
Much better than one big 20 Amp. fuse which could burn a socket completely.

The two fuse for the 5V supply I moved to the right.
Right in the middle I put my Bridge Board.

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Thanks Peter for your help! I like your setup. Mine is way to high and it blew a transistor. Could it be the capacitor or bridge? It is to high at the playfield.
thanks!

In which circuit is your problem?
GI has no bridge rectifier or capacitor.

If it is in the coils circuit, it can be the bridge rectifier.
Unplug 2J12, 2J11 & 2J9 and retry.
Perhaps it is better to start your own repair posting.

Didn't know br wasn't going to gi. I'll start a thread.
thanks!

Thanks for your help. You were right about me not measuring voltage correctly. Turns out the problem was a short on the playfield i'm still trying to track down.

I'm getting ready to do another system 4 driver board with mosfets and had some last questions.

Would FQPF22P10 be an even better option as it adds some additional Vsg headroom (30V). At a nickel more each at GPE, seems silly not to just go for these when you are talking about an additional .40c per board no? Is there some other factor that would make this a bad idea?

Also if I do use the FQPF22P10 or the FQP17P06, can I use 1.2K resistors to replace the 27Ohm resistors on top AND use 1.2K on the bottom side for the voltage divider or should I use 1K on top and 1.2K on the bottom?

Looking at this a little more, what is the goal here? To divide the voltage in half? If half, the resistors should match, but what is the goal, divide or lower?

Thanks!

Just picked up a sys 6, Laser Ball, gotta go through this thread!!

Probably a n00b question - but the bridge rectifiers, looks like my lamp rectifier (13.5v) has been burning up for a while. What I have is a KBPC3502. Is this a drop-in replacement?

https://www.digikey.com/product-detail/en/comchip-technology/KBPC3502-G/641-1855-ND/3300079?utm_campaign=buynow&utm_medium=aggregator&WT.z_cid=ref_findchips_standard&utm_source=findchips

A friend has a Flash with a Rottendog MPU-327, CPU/Driver combo board.

The test buttons on the coin door do not work at all. All connectors are hooked up, but I noticed that all 16 Dip switches that control the audits/high scores, etc., are all set to Off. Would this have anything to do with it or do I need to look elsewhere?

Thanks,

Alan

They shouldn't have any effect on non-sys3 games. Even on those they only do anything when you go into diagnostic mode via the side button of the mpu.

I'm doing some work on my Firepower and noticed there is no thermistor at the incoming power. I'm guessing this was a later addition - WPC? Is it worthwhile to add on System 6, 7, or 11 for that matter? I imagine it doesn't hurt, so thought I would.

It looks like there should be one per the schematics. I think they were used in all williams SS

I just found a schematic, and this one shows there is a varistor but no thermistor (are you mixing them up?), just like my machine.