(Topic ID: 196153)

U22 Error (WPC-S)

By RonaldRayGun

6 years ago



Topic Stats

  • 10 posts
  • 6 Pinsiders participating
  • Latest reply 4 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

You're currently viewing posts by Pinsider noflip95.
Click here to go back to viewing the entire thread.

#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)

2 weeks later
#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

Promoted items from the Pinside Marketplace
$ 9.95
Eproms
Pinballrom
Eproms
From: $ 27.00
Boards
KAHR.US Circuits
Boards
$ 85.00
6,000 (OBO)
Machine - For Sale
Ann Arbor, MI
$ 11.95
Playfield - Toys/Add-ons
ULEKstore
Toys/Add-ons
From: $ 64.95
Cabinet - Sound/Speakers
PinSound
Sound/Speakers
$ 29.99
Cabinet - Shooter Rods
Pinball Shark
Shooter rods
$ 399.95
Lighting - Led
Pin Stadium Pinball Mods
Led
From: $ 20.00
Playfield - Decals
Flashinstinct
Decals
$ 109.95
Electronics
PinSound
Electronics
$ 54.99
Cabinet - Shooter Rods
Lighted Pinball Mods
Shooter rods
$ 329.99
Lighting - Other
Lighted Pinball Mods
Other
From: $ 110.00
Playfield - Other
Arcade Upkeep
Other
$ 15.00
Playfield - Plastics
Pinball Haus
Plastics
$ 5.00
Playfield - Protection
UpKick Pinball
Protection
$ 199.95
Electronics
PinSound
Electronics
$ 37.50
Boards
Pinball Haus
Boards
6,500 (OBO)
Machine - For Sale
Northglenn, CO
$ 49.99
Cabinet - Toppers
Lighted Pinball Mods
Toppers
From: $ 9.99
Eproms
Matt's Basement Arcade
Eproms
From: $ 209.00
$ 54.99
Cabinet - Shooter Rods
Lighted Pinball Mods
Shooter rods
From: $ 159.95
Cabinet - Sound/Speakers
PinSound
Sound/Speakers
$ 39.00
Cabinet - Other
Arcade Upkeep
Other
$ 219.00
Gameroom - Decorations
Lit Frames
Decorations
$ 41.99
Lighting - Interactive
Lee's Parts
Interactive
$ 12.00
Tools
Nezzy's Pinball Prints
Tools
$ 10.00
Playfield - Toys/Add-ons
Pinball Haus
Toys/Add-ons
Great pinball charity
Pinball Edu

You're currently viewing posts by Pinsider noflip95.
Click here to go back to viewing the entire thread.

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 https://pinside.com/pinball/forum/topic/u22-error-wpc-s?tu=noflip95 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.