I am not a tech by any means but when I got my dirty harry pinball from a guy recently, the same thing was happening to the left flipper. I could only scroll with the right flipper and not the left. So I looked at the flipper optical board? and cleaned the small bulbs with a soft tooth brush. The pin had been sitting for years with no maintenance. That seemed to do the trick since it worked perfectly after that. I was fearing the worst but it was just dirty. Hope your issue is that easy...

Opto couplers on your MPU ? Lane change switches on your flipper buttons or EOS switches ?

Depends on what is in your game.

Your game doesn't have flipper button opto boards like Dirty Harry.

LTG : )

Radical is showing as System 11C. The 4N25 optocoupler should be on the interconnect board.

http://www.pinwiki.com/wiki/index.php?title=Williams_System_9_-_11#4N25_Opto_Couplers_in_the_Switch_Matrix

Something similar happened to me when I got a high score. Entered my first initial and pressed the start button to lock it in, entered the second initial and pressed the start button to lock it in.....and nothing....

Ended up timing out and the only initial I entered was the first one. Cleaned the contacts and it's been working well ever since.

Unless you have a stacked switch on your flipper EOS (not likely since this is a System 11C) it is likely to be the 4N25 optocoupler on the interconnect board. The flipper switches only complete the +50VDC to ground. There is no signal to the CPU that the flipper has energized. Not even the EOS does this. The EOS only interrupts power to the power winding on the flipper coil. The detection is via the 4N25 optocoupler.

If the game is a System 11C (I'm reading the manual as I've never worked on a Radical) the EOS only interrupts current to the power winding on the flipper coil. If the EOS switch is broken you will probably blow a fuse on the auxiliary power board. The only time I've seen the EOS do anything is if there is a stacked switch off the EOS that closes when the EOS opens. I doubt you will see that in a System 11C.

If the optocoupler reads out-of-spec it's almost certainly bad.

There are 3 optocouplers on the board. 2U1, 2U2 and 2U3. It looks like 2U1 is used to detect A/C relay state. 2U2 shows as the left flipper and 2U3 shows as right flipper. This is according to a manual for System 11C. You can verify which is what by looking for continuity between the connectors and the legs of the optocoupler. The manual usually is correct but I've seen errors in them before so you should double check.

So this thread is a year old but I'm super hoping you can help me out like you did this guy. I'm having this exact same problem. I have a Maverick pin which doesn't have an inter connect board. Any chance I can just replace a couple parts like this guy did?

Maverick is Data East. There is no interconnect board and no 4N25 optocoupler. The root cause of your problem will be different.

Try with the switch matrix tests and see what works and doesn't.

Check the flipper board in the cabinet.
Most likely it has bad header pins.

first off thank you sooooooo much for responding to a thread that ended a yera ago, i had very little hope, so thanks a whole bunch. Tried the switch test and everything came up as registering except the flipper buttons. They work fine but they don't register as open when you press them during test mode. That's what you mean by switch matrix test right?

And already replaced the flipper board, brand new so no issues there.

Which flipperboard is now in the game?
It should be a 520-5076-00 board.

It's a 520-5076-00 correct.

so I discovered some more info!!! maybe you guys can help me understand it. Also I am posting this info in the maverick specific thread as well, but I feel like this issue could be considered a more general pinball issue and therefore maybe you guys could help me out... I may have annoyed the maverick thread with all my questions. sorry and thanks... anywho here is the info:

Backbox circuit board relays and their functions:

PPB/MRB board relay K1: this relay controls the solenoid L/R select circuit, and is controlled by CPU transistor Q29 (TIP122). It is extremely common for this relay to have cold solder joints! If the L/R (or A/B) select coils or flashlamps do not work, this relay should be checked. This relay is a 24 vdc 10 amp relay with two DPDT switches. There are a total of 8 solder points on this relay; two connect to the winding of the relay coil (to turn the relay on and off). The other six contacts (two distinct sets of three contact DPDT switches) are the relay switches. Source number FRL264 P024/02CK, Sega part 190-5002-00.

Im reading "this relay controls the solenoid L/R select circuit" and "If the L/R (or A/B) select coils or flashlamps do not work" as my exact issue right? like when they say L/R select i assume that are talking about selecting things with the left flipper button and right flipper button? If this is the case i think we found our problem right? now how the heck do i fix it? How does one replace a relay and what does the relay even look like?

i found this relay which says its for star wars, but maybe itll work for me as well, I can probably confirm part number in my manual: https://www.marcospecialties.com/pinball-parts/190-5002-00

Do all of your solenoids fire and flashers fire in test modes? If so you don't have a relay problem and while it has been a while since I've owned any DE game I would be really, really surprised if this problem is in any way tied to the relay. If the flippers buttons don't register in switch test but the flippers still flip you need to determine what actual switch or bits of hardware count as the flipper button in the matrix and troubleshoot that.

first out thanks bobukcat for the info. and ya I think you are very right. During test mode my flashers and solenoids do work i think. two of the flashers i believe have dead bulbs, but I just ordered replacements for those. So ya it probably doesnt have to do with what I originally thought, i was misinterpreted what it was saying. I read L/R select coils as left and right flipper select buttons... guess not. So troubleshoot matrix got it. I ran all the switch tests through the test mode and it pops up as all switches good and then when i press start button it says im pressing start button and when balls are in trough it says all 4 balls are in trough, but sadly when i press flipper buttons nothing pops up on screen. do you kind of know an idea of how I would began troubleshooting this?

side note your avatar is sweet and Houdini is the next game i want to get in the future, i had never played it until recently and i absolutely fell in love. and my wife actually gave me the ok on that theme and she is very hard to please when it comes to pinball themes.

Thanks, Houdini was actually a birthday present from my wife last year, I really have loved the game since playing a very early production example at the Louisville show. The main reason I use it as my Avatar though is because the picture includes our NKY league logo that one of member's created.

The flipper "switch" that the matrix should see if actually generated on the Solid State Flipper Board (SSFB), so see pages 74 and 90 in the manual and work from there: https://www.ipdb.org/files/1561/Data_East_1994_Maverick_Full_Manual.pdf

Unfortunately the SSFB troubleshooting flowchart doesn't mention the switches not registering. Good luck!

Additional info: make sure switches 57-61 are working, if not you probably have a broken wire or a bad connection somewhere on that Green/Gray switch drive wire.

already replaced the flipper board so its not an issue with actual board, but ya i looked through the manual and couldnt find anything about this particular issue. I always just assumed if the flippers actually worked then they would obviously easily work as buttons, but i guess not.

I'd troubleshoot it just like any other switch matrix issue, check every other switch that is on the same drive circuit and trace the corresponding wires.

Makes sense. For some reason I wasn't understanding that until recently. I will do my best to check that out this weekend and if I have more questions I'll come back. Thanks for all the help.

**I couldn't resist posting in the Maverick club.

I also would look at all the switches in column 8 to see if any of them have a green-gray wire broken. It is best to give the wires a small tug as the heat shrink can hold a broken wire in place looking like it is connected. Also look to make sure that green-gray wire(s) are soldered to the middle connection of the playfield switches. The switches for 63 and 64 are likely physically different than the other six in that column.

maverick switch matrix (resized).png

Oh dude you found me out. Ya I may or may not have posted this issue in way too many places. Thanks again for the help.

Do the led's blink on the SSFB when you press the flipper buttons?

The switches from the SSFB are done electronic.
Here is a part of the schematics which show the 3 transistors for each flipper.
The red line is the "Switch Drive" and should be the Green-Gray wire.
The pink line is the "Switch Return 8" and activates sw. 64 (White-Gray wire).
The green line is the "Switch Return 7" and activates sw. 63 (White-Violet wire).
The blue line is for the upper flipper and isn't used as you can see on the left side of the image.

If neither of your flipper switches register, check the green-gray wire for good connection.

For the record, 520-5076-00 is a modified 520-5033-03 board.
Same functions, but with an added safety for failing EOS switches.

Peter
flipperboard02 (resized).jpg

Yes when I press the flipper buttons the appropriate light blinks on the flipper board.

Ya it's actually possible that I have the older board, but I did purchase that newer board with the safety feature. Hooked it up and got exact same results so left the original board in there. I didn't know about the safety feature though. Maybe I should switch it out for the new one either way.

Ok so green grey wire is possibly the culprit. I have to make sure it has a good connection. Now attached isn't a picture of that exact connector but my connectors either look like one of these and I'm wondering do you normally like take out the wire and make sure the metal has cut it enough so that metal is touching wire or do you do something else to make sure connection is good?

Screenshot_20190625-134537_Gallery (resized).jpg

Screenshot_20190625-134613_Gallery (resized).jpg

Ps. Thanks so much for diagram you found and is this in theory the green grey wire? This is connected to my cpu board so Ill probably check connection there but more likely much further down by flipper board but ya is this the culprit color?

20190625_135151 (resized).jpg

Screenshot_20190625-135054_Gallery (resized).jpg

You need to test the other switches (57-62 in the matrix pictured above) on that same drive, everything else is pretty much a waste of your time at this point.

Ok so that whole right column. Ya that makes sense. Then I can see if it's the whole column or just specific switches. Got it!

Green and grey

Nope, wroung connector.
These are the coils.

You need to check CN8 (more to the right).
Check if the wire is firmly seated.
Like Bobukcat said, check the whole column for good operation.

Data_East_CPU_520-5003-02_layout (resized).jpg

Ohhhhh see now even though I thought that was a really stupid question, I'm happy I asked. So it's the GREEN with the grey. Not the GREY with the green. Super good to know. Thank you so much for checking that and clarifying. Got it and will do!

Screenshot_20190626-132521_Gallery (resized).jpg

well Im finally no longer sick so i went out to the machine and finally tested all the stuff you guys had been trying to explain to me for several posts. Im super sorry for being such a dunce.... anywho. here is the verdict. the entire right column on the switch matrix doesn't work. Im like 90 ish percent sure that the rest of the switches work. There are a few lights and flashers that i cant get working but i believe those are on a different deal so it doesnt really matter for this topic. ok so all of column 8 which is the entire green grey wire. a couple odd things to note is first off the right flipper doesnt have a green grey wire at all. the left does. also there two green grey wires that are kind of connected together running side by side going from some of the switches to other switches and going to what looks to be a ground bolt randomly. I can take some pictures if that would help. are you guys able to help me out on what my next steps should be? and/or are you guys able to send me some pictures of your underside slash your flippers so i can see how my setup is different. also on the switch matrix it says row (return) CN8-9. now the green grey wire is definitely coming out of the CN8 plug, but is the green grey wire supposed to be going to the CN9 plug as well? is that what return means?

Glad to hear you are feeling better.
I figured the whole column wasn't working. At the top of the chart, it shows the column is driven by Q48. Test out this transistor and compare your results to Q49 or Q50. Likely you will see a big difference in how Q48 measures against Q49Q50.

Set your meter to 2k ohms. Test the transistor outer pin to outer pin, then the middle to one of the outer pins and then middle to the other outer pin. One of these combinations is likely to show the transistor is shorted.

Ok let's assume the transistor ends up being shorted, can I just purchase a new transistor and remove the old one and solder in the new one? And where is this transistor that I'm testing located.. picture attached location?

And thanks so much for the info and getting back to me so quick

Screenshot_20190706-203019_Gallery (resized).jpg

Yes. 2N3904. Yes, correct location.
If there is a Fry's Electronics store near you, NTE part 2N3904 may be available there.

Make sure when you do any ohm test, that is done with the game powered off.

Remember that those wires for the switch matrix won't actually be going to your flippers, they go to the SSFB which generates the switch hits for entering initials, changing lanes, etc.

Glad you're feeling better!

Ohhhhh that makes sense because ya the green grey wire was no where to be found on the right flipper, but oddly enough I believe there was a green grey wire at the left flipper... Maybe it was a different green grey wire or maybe I'm going a bit color blind ha ha. Those green grey wires sure do look a lot like the green purple and the green something else.

There are three switches in the column near the left flipper (Left Return, Left Outlane and Left Sling) so yeah, that Green-Grey wire is definitely in that area.

Ohhhhhh that makes even more sense! Thank you.