(Topic ID: 196153)

U22 Error (WPC-S)

By RonaldRayGun

6 years ago



Topic Stats

  • 10 posts
  • 6 Pinsiders participating
  • Latest reply 8 months ago by Zeegske
  • Topic is favorited by 1 Pinsider

You

Linked Games

Topic Gallery

View topic image gallery

Test_PIC (resized).jpg
Screenshot from 2017-08-20 16-56-21 (resized).png
#1 6 years ago

I get U22 Error on startup. U22 is the PIC security chip.

I have low on pins 23,24,25 on U22 which are connected to pins 12,15,16 on U14 (see schematics).
I also have low on pins 14,15,16,17 on U22 which are connected to pins 3,4,7,8 on U24 (note that these are mislabeled as 13,14,17,18 in the schematics).

I have replaced U14 but it didn't change the low pins.
Can I deduce that U22 is bad or is it possible that U24 or U13 are the culprits?

Thanks.

Screenshot from 2017-08-20 16-56-21 (resized).pngScreenshot from 2017-08-20 16-56-21 (resized).png

#2 6 years ago

Change u22 pic

#3 6 years ago

Thanks mate. I will order a PIC but it'll take a couple of weeks to ship from the US. In the mean time, I was wondering if there could be something else that is causing the problem.

2 weeks later
#4 6 years ago

hmmm... not mandatory

First: indeed there is a big error on WPC-S schematic, the nibbles D0..D3/D4..D7 are inverted on U24. Of course, this is only a pin number error, as D0 goes to D0's CPU. No bus inverted here, only an error on pins numerotation.

The RD wires are the "Read Bus" for the SECURITY PIC. It as two purposes : read the commands/datas from CPU, and read the rows returns from matrix.
If you have RD5..RD7 grounded, you should first suspect U13 74LS240 that is the matrix return (part U13A for the MSB).

Of course, if the PIC (U22) is unable to read commands from CPU, the outputs can have strange behaviour.
First, fix the inputs problem. Note that:
- Deffective U24 has no effect on RD bus, so it is unlikely that this is the case.
- Deffective U23 has also no effect on RD bus.

Check if you see activity on RD0 (U14 pin 9) ~ using a scope, or by default, a voltmeter (any voltage different from 5V or ground):
If yes, this means that the PIC periodicaly read the inputs from U14. Thus, U22 is not dead. It detect command latched (both U14 pin 11 - for the latch - and U22 pin 1 - commands detection), then it read the latch using RA1 port (OC, U14 pin 1).

Usually, when a SECURITY PIC is dead... it is fully dead ! barelly partially. So, if the command detection works... U22 is alive !

Note that... if you really need to replace U22, I well know some French guys that can provide, a personnalized SECURITY CHIP with the serial number you want (and not 999999 or something like)

#5 6 years ago
Quoted from noflip95:

hmmm... not mandatory
First: indeed there is a big error on WPC-S schematic, the nibbles D0..D3/D4..D7 are inverted on U24. Of course, this is only a pin number error, as D0 goes to D0's CPU. No bus inverted here, only an error on pins numerotation.
The RD wires are the "Read Bus" for the SECURITY PIC. It as two purposes : read the commands/datas from CPU, and read the rows returns from matrix.
If you have RD5..RD7 grounded, you should first suspect U13 74LS240 that is the matrix return (part U13A for the MSB).
Of course, if the PIC (U22) is unable to read commands from CPU, the outputs can have strange behaviour.
First, fix the inputs problem. Note that:
- Deffective U24 has no effect on RD bus, so it is unlikely that this is the case.
- Deffective U23 has also no effect on RD bus.
Check if you see activity on RD0 (U14 pin 9) ~ using a scope, or by default, a voltmeter (any voltage different from 5V or ground):
If yes, this means that the PIC periodicaly read the inputs from U14. Thus, U22 is not dead. It detect command latched (both U14 pin 11 - for the latch - and U22 pin 1 - commands detection), then it read the latch using RA1 port (OC, U14 pin 1).
Usually, when a SECURITY PIC is dead... it is fully dead ! barelly partially. So, if the command detection works... U22 is alive !
Note that... if you really need to replace U22, I well know some French guys that can provide, a personnalized SECURITY CHIP with the serial number you want (and not 999999 or something like)

Thanks @noflip95. This is useful info!
I have pulse signal on RD0..RD4, so there is some activity.
I will replace U13 and report back.

#6 6 years ago

The common fault is the two latches ('374s) that are buffering the PIC. Someone shorts coil voltage to the switch matrix, and it takes out the security chip and one or both latches.

Swap in a known good security chip from another game. If it comes up with the game and serial number (vs just 0's) then you know its the first security chip. If its still all 0's, then you know its something else.

-- I provide a "all 9's" version of the replacement security chip.
-- www.shiftedbits.com

1 week later
#7 6 years ago

I replaced U13 but still have RD5...RD7 stuck low.

#8 6 years ago
Quoted from RonaldRayGun:

I replaced U13 but still have RD5...RD7 stuck low.

Damn!

There is a trick you can try to identify if the source of the problem, is the PIC or another chip:

- Remove the U22 from its socket.
- Connect a wire (like "Dupont male") between pin 4 (VSS gnd) and pin 7 (RA1 = gate of U14) - blue wire on the picture.
- Connect another wire, between pin 2 (VDD 5 volts) and pin 6 (RA0 = gate of U13) - red wire on the picture.

This will set the U14 to output mode and disable the U13 inputs (return from matrix).
Thus the RD bus, will reflect the input command sent by the the CPU (as U13 is a latch, the command should be visible for a very short time, but enough to be noticeable).

When the CPU start, it first send commands to retrieve the serial number (like 7x commands - thus having RD6, RD5 set to "1").
At startup, if you see some activity on pins 23/24 (RD5/RD6) this means that the issue is the PIC (as U13 and U14 works fine).
If there is no activity, then this means that the problem is somewhere else.

Test_PIC (resized).jpgTest_PIC (resized).jpg

5 years later
#9 1 year ago

I got bad U22 on Corvette and it works with a security chip from an other Corvette which definitely means my PIC is not working.
Is it possible to reprogram it or buy an empty new one? I have the TL866 programmer.

4 months later
#10 8 months ago
Quoted from noflip95:

hmmm... not mandatory
First: indeed there is a big error on WPC-S schematic, the nibbles D0..D3/D4..D7 are inverted on U24. Of course, this is only a pin number error, as D0 goes to D0's CPU. No bus inverted here, only an error on pins numerotation.
The RD wires are the "Read Bus" for the SECURITY PIC. It as two purposes : read the commands/datas from CPU, and read the rows returns from matrix.
If you have RD5..RD7 grounded, you should first suspect U13 74LS240 that is the matrix return (part U13A for the MSB).
Of course, if the PIC (U22) is unable to read commands from CPU, the outputs can have strange behaviour.
First, fix the inputs problem. Note that:
- Deffective U24 has no effect on RD bus, so it is unlikely that this is the case.
- Deffective U23 has also no effect on RD bus.
Check if you see activity on RD0 (U14 pin 9) ~ using a scope, or by default, a voltmeter (any voltage different from 5V or ground):
If yes, this means that the PIC periodicaly read the inputs from U14. Thus, U22 is not dead. It detect command latched (both U14 pin 11 - for the latch - and U22 pin 1 - commands detection), then it read the latch using RA1 port (OC, U14 pin 1).
Usually, when a SECURITY PIC is dead... it is fully dead ! barelly partially. So, if the command detection works... U22 is alive !
Note that... if you really need to replace U22, I well know some French guys that can provide, a personnalized SECURITY CHIP with the serial number you want (and not 999999 or something like)

Replacing U13 solved the issue regarding mu U22 error. Now to find out why U13 failed....

Promoted items from Pinside Marketplace and Pinside Shops!
$ 9.95
Eproms
Pinballrom
 
From: $ 225.00
Lighting - Interactive
Professor Pinball
 
Wanted
Machine - Wanted
Mequon, WI
$ 63.95
Eproms
Pinballrom
 
$ 11.95
Playfield - Toys/Add-ons
ULEKstore
 
$ 259.99
Cabinet - Toppers
Lighted Pinball Mods
 
$ 49.99
Cabinet - Toppers
Lighted Pinball Mods
 
$ 219.00
Gameroom - Decorations
Lit Frames
 
$ 20.00
Playfield - Protection
Pinhead mods
 
7,495 (OBO)
Machine - For Sale
Plantsville, CT
$ 26.95
Playfield - Decals
Pinball Pimp
 
$ 15.00
Playfield - Plastics
Pinball Haus
 
$ 329.99
Lighting - Other
Lighted Pinball Mods
 
7,000
Machine - For Sale
Newburgh, NY
$ 10.00
Playfield - Toys/Add-ons
Pinball Haus
 
$ 35.00
Cleaner
PFX PinMods
 
From: $ 5.99
Playfield - Plastics
The Pinball Scientist
 
From: $ 20.00
Playfield - Decals
Pinball Invasion
 
From: $ 9.99
Eproms
Matt's Basement Arcade
 
$ 29.99
Cabinet - Shooter Rods
Pinball Shark
 
$ 41.99
Lighting - Interactive
Lee's Parts
 
$ 8.50
Playfield - Decals
Pinball Haus
 
$ 17.50
Playfield - Plastics
Pinball Haus
 
5,175 (OBO)
Machine - For Sale
Los Angeles, CA
Hey modders!
Your shop name here

Reply

Wanna join the discussion? Please sign in to reply to this topic.

Hey there! Welcome to Pinside!

Donate to Pinside

Great to see you're enjoying Pinside! Did you know Pinside is able to run without any 3rd-party banners or ads, thanks to the support from our visitors? Please consider a donation to Pinside and get anext to your username to show for it! Or better yet, subscribe to Pinside+!


This page was printed from and we tried optimising it for printing. Some page elements may have been deliberately hidden.

Scan the QR code on the left to jump to the URL this document was printed from.