WPC95 Rev 9 U27?

Does anyone know what component U27 should be on a WPC95 Part Number 5764-14553-09 MPU board? In the normal WPC-95 schematic, U27 would normally be a 74LS02. But on this revision board, there is no way it can be a 7402 (Outputs are grounded, inputs go to drive other ICs etc.).

I am working on an acid damaged board out of a Tales of the Arabian Nights. Someone had already pulled U5 and U27 and then gave up. I am pretty sure I have the board repaired but need to figure out what goes in U27 (source of Driver Board Data Buffer Enable signal).

I have found a few reference to 3 different versions of the board and a couple of photos of a -09 but none are clear enough to determine the correct IC for U27. The Date code on this board is 22-96

Any Help would be greatly appreciated.

I have attached an image. Traces around U27 are drastically different than the normal WPC95.

WPC95-09.JPG

#2 7 years ago

CHD

Cheddar

GoldenStatePin

Lodi, CA

11y 117K 5,181 17 10

The manual has 74LS08

#3 7 years ago

---

ForceFlow

Pinside Moderator

9y 238K 31,358 268 14

According to the scematics, 74LS08

20161223203415143 (resized).jpg

20161223203410503 (resized).jpg

#4 7 years ago

BIF

CactusJack

Pinside member

Thanks Guys but that still doesn't jive with this board layout. In an 02 or 08, Pins 2 and 3 are inputs and pin 1 is the output. On this layout, Pin 3 goes to drive pins 1 and 19 of U12 (Driver board buffers).

It has to be something like a 74LS32 where the gates are turned around.

#5 7 years ago

TOX

ChrisHibler

Chris' Pinball Repair

Chesterfield, MO

12y 120K 9,996 46

It's an LS08.
This is my pic...it's in the PinWiki somewhere, but I found it here too.
https://pinballsupernova.files.wordpress.com/2015/11/3-battery-deplete.jpg
--
Chris Hibler - CARGPB #31
http://www.ChrisHiblerPinball.com/Contact
http://www.PinWiki.com - The Place to go for Pinball Repair Info

#6 7 years ago

BIF

CactusJack

Pinside member

Thanks, I guess the one pinout image I pulled up of the internet for an 08 was wrong. It showed an 08 like an 02.

#7 7 years ago

ZAZ

zaza

Pinside+ Frequent

Two years ago I made this picture from a 5764-14823-04 CPU-board and drew a 74LS02 at U27 so there is probably another version as well. To bad no clear photos made from it so can not be 100% sure.

But you can verify, if on your board U27-3 has continuity to U12-1, then U27 is a 74LS08.

5764-14823-04 Zaz.jpg

#8 7 years ago

ZAZ

zaza

Pinside+ Frequent

Found the differences for U27 in manual oct'95 and jul'97
versions u27.jpg

#9 7 years ago

TOX

ChrisHibler

Chris' Pinball Repair

Chesterfield, MO

12y 120K 9,996 46

Quoted from zaza:
Two years ago I made this picture from a 5764-14823-04 CPU-board and drew a 74LS02 at U27 so there is probably another version as well. To bad no clear photos made from it so can not be 100% sure.
But you can verify, if on your board U27-3 has continuity to U12-1, then U27 is a 74LS08.

Sascha,
I don't have the WPC-95 image in the PinWiki like I do the WPC-089 image, here
http://www.pinwiki.com/wiki/index.php?title=File:WPC-089MPULayout.jpg

I'd love to add the image if you could send it to me.

Take care,
Chris Hibler

#10 7 years ago

ZAZ

zaza

Pinside+ Frequent

That WPC-95 picture has not the detailed switches and header information like the '89 board, and have no plans to add it as well.
At the moment it is nothing more than a layout with unverified component and some sketchy header info.
I prefer not to publish it in the state like it is now.

#11 7 years ago

TOX

ChrisHibler

Chris' Pinball Repair

Chesterfield, MO

12y 120K 9,996 46

Quoted from zaza:
That WPC-95 picture has not the detailed switches and header information like the '89 board, and have no plans to add it as well.
At the moment it is nothing more than a layout with unverified component and some sketchy header info.
I prefer not to publish it in the state like it is now.

I understand. Thanks for the update my friend.
--
Chris Hibler - CARGPB #31
http://ChrisHiblerPinball.com/contact/
http://www.PinWiki.com - The new place for pinball repair info

#12 7 years ago

BIF

CactusJack

Pinside member

Quoted from zaza:
Found the differences for U27 in manual oct'95 and jul'97

Thanks Zaza,. The orange manual (version .1) obviously matches the layout/build of this board. The 74LS02 version matches the .3 manual most commonly downloadable off the net.

Your diagram could be a useful addition to pinwiki for those that do battery alkaline damage repair as U27 and U5 sit directly below the battery holder. And the 74LS08/02 design is drastically different.

#13 7 years ago

ZAZ

zaza

Pinside+ Frequent

OP
Quoted from CactusJack:
Your diagram could be a useful addition to pinwiki

I feel some pictures coming next year

#14 7 years ago

KIM

Pin_-_K

KIMBALL's PINBALL's

Lakeside, TX

11y 66,350 665 31

Can't seem to get the pic off my phone, but U27's a SN74LS08N on our TOTAN.

3 weeks later

#15 7 years ago

ZAZ

zaza

Pinside+ Frequent