You will be poking at these parts. They are on the CPU board.

U-50 is a TTL level NOR chip. It's truth table is below. Zeros are lows and ones are highs.

Q-78 Is a signal transistor, part # 2n4401

Q-79 Is a Darlington Pair high current transistor. It actually is 2 transistors, 2 resistors and a diode in one package.

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Sounds like a bad ribbon cable.

Yes this is a standard led bulb, it is used in the GI (general illumination). GI doesn't need non ghosting bulbs.

The lamp sockets are corroded or loose fitting. You can squeeze the sockets with pliers so the bulbs fit tighter.

Does anything odd happen if you put incandescent bulbs in those spots?
The bulbs under the return frames are GI, not controlled lights, and shouldn't have any chance to "ghost".

I can't really tell from the pic but is that bulb an old style LED, not an SMD bulb? If so, maybe it's just a crappy bulb. As noted above, I'd try an incandescent as well as a different LED...especially if that's an old style LED. Those things suck. SMD all the way or keep it original with incandescent, IMO.

Oh, and back on my lamp matrix issues that I posted foreverrrrrrrrrrrrr ago... My friend has had my High Speed for a bit and was finally able to figure out what was wrong. Someone wired the shoot again light incorrectly (wasn't me!) ... so that blew out both the row AND the column, causing all sorts of weird behavior. Fixed now.

When I go and pick it up, I need to install the MRS switch to see if that fully resolves my ramp switch issue...and then I just need to play the sh1t out of it. I miss her.

Have to be honest. I'm good with the items you are talking about. How does one probe them exactly?

Have to be honest. I'm good with the items you are talking about. How does one probe them exactly?

There are 2 clips to connect, the black to ground just to the left of the battery holder and red clip to the 5 volt test point by the ram chip. Set the switch to TTL because that's the logic chips you will be testing. Now you can touch the pointed tip to places that needs testing. So if you place game in solenoid test, and lock it on solenoid #22. The machine will now turn on the enable signal ( U-50 pin 6) and also send a pulsed test signal to U-50 pin 5. The base of Q-78 needs a high signal to turn on. If you look at the truth table for a NOR chip you will see there is only one way to get a high output, you need to have both inputs low. Now with the machine in test, U-50 pin 6 should be low and pin 5 will be high with low pulses. When you test pin 4 you should get a low with a high pulse. If all this test correctly you know that U-50 is working. Then you move on to Q-78 and test. The pin out shows that the middle lead is the base, and if U-50 is working correctly there should be a low with high pulses at Q-78 base lead. If this is correct you move on to the base of Q-79. The pin out shows that the left lead is the base, If Q-78 is working it will have a high pulse going from the collector thru it and out the emitter to Q-79 base lead. If the base of Q-79 has a low with a high pulse on it then you know that Q-78 is working correctly. Lastly probe Q-79 collector while still in solenoid test, You should get a high signal with a low pulse on it. If you don't then the TIP 122 is bad. TIP 122s can be replaced with TIP 102s as they are 60% stronger.

Has anyone with a clear ramp bothered to mess with the far right rear plastic? It bugs me how it lifts up. Makes sense with the black ramp, but not with clear.. imo

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Okay, if I'm doing this correctly-
U-50 pin 6 = low
U-50 pin 5 = high
U-50 pin 4 = low

However, I'm not seeing any indication of pulsing. I bought the exact logic probe you have. It looks like the other light should blink for pulses? Can you direct me to something else to check that should pulse just so I can verify that probe works and I can see how pulses are indicated?

Sounds like you are doing this correctly to me.

Did you have the game in solenoid test? On solenoid #22?

Yes, coil 22. Top flasher.

Try this again on a working coil for a logic probe test. Do solenoid #21 this time.

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Do you have the pulse/mem switch set to pulse?

Using the same U-50 chip and same pins I am getting the same results.

U-50 pin 6 L
U-50 pin 5 H
U-50 pin 4 L
No pulsing.

I've included pics so you can make sure I'm doing it correctly.

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When you check a different solenoid the pins on U-50 are different and so are the transistors.

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Okay, I'll take the hit on testing the wrong pins. Went back and did it again.

U-50 pin 3 L
U-50 pin 2 H
U-50 pin 1 L
Again, no pulsing.

I did poke a few random pins to test as to whether or not probe is registering them. I did find a pin that made it pulse.

When you were on solenoid 21 test, was the lower pop bumper firing? Did you see the green/red arrows on the probe alternating while testing?

Nothing was firing and don't think arrows were alternating. The pulse light flickered once or twice but that's all.

Now we are getting somewhere.

Start the solenoid test over again from the beginning, note down which solenoids don't work.

Interesting. Seems that 17 through 22 are not working in test mode. Guess I should check it regularly!

Ok, this is what I was thinking was going on. Lets go back one chip and do some more testing. Put the game back in solenoid test for #22. Find U-49 and tests pins 13 and 12. Both should be pulsing in test.

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Both test high with no pulse.

Since the inputs for U-49 come from three different chips which I doubt all three are bad at the same time so I'm going to assume that U-49 is bad. If you had a pair of electronics mini shear cutters I would have you cut U-49 pin 13 in half. This would isolate U-49 from U-54. Then you could test the trace instead of the chip leg for the pulses.

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I see from you CPU pics that U-51 and U-54 are both in sockets, you could remove both chips and swap them. Then retest for pulses on U-49 as before. But you need to be very careful when removing and installing chips so you don't damage the chips or sockets.

Swapped chips. Both still test high with no pulse. Still no coil firing during test.

So then U-49 must be bad. Are you capable of this type of repair?

Also have you tried the top flashers in a game? Just because they don't work in solenoid test doesn't mean they wont work during a game now that you fixed the bulb socket.

Unsolder and resolder U-49? Going to need to be. Also have an nvram socket to install. Bought the cheap ass solder sucker off Amazon. Soldered lots of crap over the years, but don't recall working on circuit boards before.

Yes, been playing game a lot. No flashers during play.

Ok so put the game in solenoid test on #22. Probe U-50 pin 5, then push one of the 2 upper play field switches that trigger the upper flashers. Does pin 5 switch from high to low?

The rollovers? Negative.

Normally the 6 special solenoids are controlled by a switch on the playfield, but this special solenoid is controlled by the computer. Which means U-49 has to work for these flasher to work during game play. The other 5 special solenoids has playfield switches so they work during a game but not in test. If you want to do a final test you can hook up a jumper wire to the ground braid and touch the other end to the connector J-19 pin 9. If the driver and predriver and the nor chip are working the flash lamps will light when pin 9 is grounded.

Anyone have a left side outlane plastic - mine is cracked.

Maybe someone bought the whole plastic kit and can sell me just this piece?

I don't need the metal piece just the plastic.

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item found - thanks all who repsonded

Check ebay.
So someone had each piece (more or less) listed individually.

Edit:
Found the listing for the right side:

ebay.com link: Williams High Speed Pinball Machine Inlane Plastic 541 9 FREE SHIP

Yes it does flash when jumped this way. So I'm replacing U-49? What is it called and where can I find one?

This a hex buffer amplifier.

https://www.greatplainselectronics.com/proddetail.asp?prod=7407

Yep - right I need left - saw that already

Here is a wanted ad - now for the plastic - hope someone did a restore and has the old one laying around.

https://pinside.com/pinball/market/classifieds/ad/108825

***found*** thanks all who responded

For .85 each is it worth buying extras? Haven't checked the shipping yet.

Hi all, I have been working some on a cpu board. Everything works when playing but when you go to diagnostic mode at first none of the special solenoids would fire. I replace Q72 and Q73 along with Q 79 and Q 78. Now everything but the R pop works in diagnostic mode. I was looking at the caps to the one side of them and it looks like they are soldered on top each other. Is this a normal thing or what is going on there? It also to me looks like C 70 isn't as it should be. This is also in the circuit that has issues. I'm mainly wondering is this normal for this board? I forgot that I also replace u45 and u49

Thanks in advance.

Troy

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I usually buy a few of everything I get to make shipping seem better. You could add some 2n4401, TIP 102, 1n4007 for the future.

You have a late run 11a board. Those are zener diodes that were added from the factory as an improvement to the board. The 11A boards have a place on the circuit board for the zener diodes with labeling.

C-70 should have a zener on it just like the other 5, but this is not the cause of your issue.

Thanks Grumpy, so would you suggest putting a zener on top of c 70? And what would be the specs? I wasn't sure what was going on with this.

Going to put my ignorance out here for all to see.... Can anyone point out which chip I am removing to install an nvram socket/chip?

I probably have that piece. I did replace my whole set. I am out of town until Next sunday but will check when I get home.