• Tech: Game Plan CPU

    From gtriley@yahoo.com@gtriley@yahoo.com to rec.games.pinball on Wednesday, March 02, 2022 04:01:34
    From Newsgroup: rec.games.pinball

    Flashes 4 times then stops. I have changed U17 and U4 as the repair guide states. I have tested continuity from all pins, I also went backward to U5 and changed that. Still, only 4 flashes. Any suggestions are appreciated.
    --- Synchronet 3.19a-Win32 NewsLink 1.113
  • From John Robertson@spam@flippers.com to rec.games.pinball on Wednesday, March 02, 2022 07:05:33
    From Newsgroup: rec.games.pinball

    On 2022/03/02 4:01 a.m., gtriley@yahoo.com wrote:
    Flashes 4 times then stops. I have changed U17 and U4 as the repair guide states. I have tested continuity from all pins, I also went backward to U5 and changed that. Still, only 4 flashes. Any suggestions are appreciated.

    You need a Logic Probe or Oscilloscope at this point.

    Check inputs to U14 - pins 20 through 23 - they should all be pulsing.

    If good then check U14 outputs pins 14 - 17 inclusive, again they should
    be pulsing.

    If bad, check U17 pins 37 through 40 inclusive, are they all pulsing? If
    yes, then there is a connection problem between U17 and U14 pins. If no,
    then do a continuity check to ground or Vcc on those four pins - any
    shorted to ground or Vcc?

    I have a Game Plan pinball support page (added the above to) here:

    https://flippers.com/gameplanTips.html

    John :-#)#
    --
    (Please post followups or tech inquiries to the USENET newsgroup)
    John's Jukes Ltd.
    MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
    (604)872-5757 (Pinballs, Jukes, Video Games)
    www.flippers.com
    "Old pinballers never die, they just flip out."
    --- Synchronet 3.19a-Win32 NewsLink 1.113
  • From gtriley@yahoo.com@gtriley@yahoo.com to rec.games.pinball on Thursday, March 03, 2022 03:35:25
    From Newsgroup: rec.games.pinball

    On Wednesday, March 2, 2022 at 10:05:53 AM UTC-5, John Robertson wrote:
    On 2022/03/02 4:01 a.m., gtr...@yahoo.com wrote:
    Flashes 4 times then stops. I have changed U17 and U4 as the repair guide states. I have tested continuity from all pins, I also went backward to U5 and changed that. Still, only 4 flashes. Any suggestions are appreciated.
    You need a Logic Probe or Oscilloscope at this point.

    Check inputs to U14 - pins 20 through 23 - they should all be pulsing.

    If good then check U14 outputs pins 14 - 17 inclusive, again they should
    be pulsing.

    If bad, check U17 pins 37 through 40 inclusive, are they all pulsing? If yes, then there is a connection problem between U17 and U14 pins. If no, then do a continuity check to ground or Vcc on those four pins - any
    shorted to ground or Vcc?

    I have a Game Plan pinball support page (added the above to) here:

    https://flippers.com/gameplanTips.html

    John :-#)#

    --
    (Please post followups or tech inquiries to the USENET newsgroup)
    John's Jukes Ltd.
    MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
    (604)872-5757 (Pinballs, Jukes, Video Games)
    www.flippers.com
    "Old pinballers never die, they just flip out."


    Hello John, Thank you for the suggestions.
    Here is where I am at as of 11pm last night.
    Everything you mentioned is good except, U14 pin 2 is being pulled to ground. This does not happen on a known good board.
    U14 pin 2 goes to U19 pin 12 and then to U21 pin 1.
    At that point I went to bed.
    I have to work on a car this morning and later I will get back to this.

    Regards
    George
    --- Synchronet 3.19a-Win32 NewsLink 1.113
  • From gtriley@yahoo.com@gtriley@yahoo.com to rec.games.pinball on Thursday, March 03, 2022 16:11:12
    From Newsgroup: rec.games.pinball

    On Thursday, March 3, 2022 at 6:35:36 AM UTC-5, gtriley@yahoo.com wrote:
    On Wednesday, March 2, 2022 at 10:05:53 AM UTC-5, John Robertson wrote:
    On 2022/03/02 4:01 a.m., gtr...@yahoo.com wrote:
    Flashes 4 times then stops. I have changed U17 and U4 as the repair guide states. I have tested continuity from all pins, I also went backward to U5 and changed that. Still, only 4 flashes. Any suggestions are appreciated.
    You need a Logic Probe or Oscilloscope at this point.

    Check inputs to U14 - pins 20 through 23 - they should all be pulsing.

    If good then check U14 outputs pins 14 - 17 inclusive, again they should be pulsing.

    If bad, check U17 pins 37 through 40 inclusive, are they all pulsing? If yes, then there is a connection problem between U17 and U14 pins. If no, then do a continuity check to ground or Vcc on those four pins - any shorted to ground or Vcc?

    I have a Game Plan pinball support page (added the above to) here:

    https://flippers.com/gameplanTips.html

    John :-#)#

    --
    (Please post followups or tech inquiries to the USENET newsgroup)
    John's Jukes Ltd.
    MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
    (604)872-5757 (Pinballs, Jukes, Video Games)
    www.flippers.com
    "Old pinballers never die, they just flip out."
    Hello John, Thank you for the suggestions.
    Here is where I am at as of 11pm last night.
    Everything you mentioned is good except, U14 pin 2 is being pulled to ground.
    This does not happen on a known good board.
    U14 pin 2 goes to U19 pin 12 and then to U21 pin 1.
    At that point I went to bed.
    I have to work on a car this morning and later I will get back to this.

    Regards
    George


    7pm update.
    U21 was bad which was causing pin 2 of U14 to go to ground.
    Replaced it with a new 74LS379.
    Still 4 flashes, but now the displays show a number 7 in all 5 displays.
    --- Synchronet 3.19a-Win32 NewsLink 1.113
  • From John Robertson@spam@flippers.com to rec.games.pinball on Friday, March 11, 2022 10:03:07
    From Newsgroup: rec.games.pinball

    On 2022/03/03 4:11 p.m., gtriley@yahoo.com wrote:
    On Thursday, March 3, 2022 at 6:35:36 AM UTC-5, gtriley@yahoo.com wrote:
    On Wednesday, March 2, 2022 at 10:05:53 AM UTC-5, John Robertson wrote:
    On 2022/03/02 4:01 a.m., gtr...@yahoo.com wrote:
    Flashes 4 times then stops. I have changed U17 and U4 as the repair guide states. I have tested continuity from all pins, I also went backward to U5 and changed that. Still, only 4 flashes. Any suggestions are appreciated.
    You need a Logic Probe or Oscilloscope at this point.

    Check inputs to U14 - pins 20 through 23 - they should all be pulsing.

    If good then check U14 outputs pins 14 - 17 inclusive, again they should >>> be pulsing.

    If bad, check U17 pins 37 through 40 inclusive, are they all pulsing? If >>> yes, then there is a connection problem between U17 and U14 pins. If no, >>> then do a continuity check to ground or Vcc on those four pins - any
    shorted to ground or Vcc?

    I have a Game Plan pinball support page (added the above to) here:

    https://flippers.com/gameplanTips.html

    John :-#)#

    --
    Hello John, Thank you for the suggestions.
    Here is where I am at as of 11pm last night.
    Everything you mentioned is good except, U14 pin 2 is being pulled to ground.
    This does not happen on a known good board.
    U14 pin 2 goes to U19 pin 12 and then to U21 pin 1.
    At that point I went to bed.
    I have to work on a car this morning and later I will get back to this.

    Regards
    George


    7pm update.
    U21 was bad which was causing pin 2 of U14 to go to ground.
    Replaced it with a new 74LS379.
    Still 4 flashes, but now the displays show a number 7 in all 5 displays.

    Hi George,

    That is odd, normally displays do not come alive until the last flash.

    Was there any corrosion on the motherboard? I'd be checking for traces
    that have given up.

    John :-#)#
    --
    (Please post followups or tech inquiries to the USENET newsgroup)
    John's Jukes Ltd.
    MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
    (604)872-5757 (Pinballs, Jukes, Video Games)
    www.flippers.com
    "Old pinballers never die, they just flip out."
    --- Synchronet 3.19a-Win32 NewsLink 1.113
  • From gtriley@yahoo.com@gtriley@yahoo.com to rec.games.pinball on Saturday, March 12, 2022 04:01:43
    From Newsgroup: rec.games.pinball

    On Friday, March 11, 2022 at 1:03:27 PM UTC-5, John Robertson wrote:
    On 2022/03/03 4:11 p.m., gtr...@yahoo.com wrote:
    On Thursday, March 3, 2022 at 6:35:36 AM UTC-5, gtr...@yahoo.com wrote:
    On Wednesday, March 2, 2022 at 10:05:53 AM UTC-5, John Robertson wrote: >>> On 2022/03/02 4:01 a.m., gtr...@yahoo.com wrote:
    Flashes 4 times then stops. I have changed U17 and U4 as the repair guide states. I have tested continuity from all pins, I also went backward to U5 and changed that. Still, only 4 flashes. Any suggestions are appreciated.
    You need a Logic Probe or Oscilloscope at this point.

    Check inputs to U14 - pins 20 through 23 - they should all be pulsing. >>>
    If good then check U14 outputs pins 14 - 17 inclusive, again they should >>> be pulsing.

    If bad, check U17 pins 37 through 40 inclusive, are they all pulsing? If >>> yes, then there is a connection problem between U17 and U14 pins. If no, >>> then do a continuity check to ground or Vcc on those four pins - any
    shorted to ground or Vcc?

    I have a Game Plan pinball support page (added the above to) here:

    https://flippers.com/gameplanTips.html

    John :-#)#

    --
    Hello John, Thank you for the suggestions.
    Here is where I am at as of 11pm last night.
    Everything you mentioned is good except, U14 pin 2 is being pulled to ground.
    This does not happen on a known good board.
    U14 pin 2 goes to U19 pin 12 and then to U21 pin 1.
    At that point I went to bed.
    I have to work on a car this morning and later I will get back to this. >>
    Regards
    George


    7pm update.
    U21 was bad which was causing pin 2 of U14 to go to ground.
    Replaced it with a new 74LS379.
    Still 4 flashes, but now the displays show a number 7 in all 5 displays.
    Hi George,

    That is odd, normally displays do not come alive until the last flash.

    Was there any corrosion on the motherboard? I'd be checking for traces
    that have given up.
    John :-#)#

    --
    (Please post followups or tech inquiries to the USENET newsgroup)
    John's Jukes Ltd.
    MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
    (604)872-5757 (Pinballs, Jukes, Video Games)
    www.flippers.com
    "Old pinballers never die, they just flip out."


    No corrosion at all, that is what bothers me.
    Continuity, good everywhere I check.
    One number 7 comes up in all displays.
    Flashes 4 times then stops every time.
    --- Synchronet 3.19a-Win32 NewsLink 1.113
  • From gtriley@yahoo.com@gtriley@yahoo.com to rec.games.pinball on Saturday, March 19, 2022 04:17:49
    From Newsgroup: rec.games.pinball

    On Saturday, March 12, 2022 at 7:01:56 AM UTC-5, gtriley@yahoo.com wrote:
    On Friday, March 11, 2022 at 1:03:27 PM UTC-5, John Robertson wrote:
    On 2022/03/03 4:11 p.m., gtr...@yahoo.com wrote:
    On Thursday, March 3, 2022 at 6:35:36 AM UTC-5, gtr...@yahoo.com wrote:
    On Wednesday, March 2, 2022 at 10:05:53 AM UTC-5, John Robertson wrote: >>> On 2022/03/02 4:01 a.m., gtr...@yahoo.com wrote:
    Flashes 4 times then stops. I have changed U17 and U4 as the repair guide states. I have tested continuity from all pins, I also went backward to U5 and changed that. Still, only 4 flashes. Any suggestions are appreciated.
    You need a Logic Probe or Oscilloscope at this point.

    Check inputs to U14 - pins 20 through 23 - they should all be pulsing. >>>
    If good then check U14 outputs pins 14 - 17 inclusive, again they should
    be pulsing.

    If bad, check U17 pins 37 through 40 inclusive, are they all pulsing? If
    yes, then there is a connection problem between U17 and U14 pins. If no,
    then do a continuity check to ground or Vcc on those four pins - any >>> shorted to ground or Vcc?

    I have a Game Plan pinball support page (added the above to) here:

    https://flippers.com/gameplanTips.html

    John :-#)#

    --
    Hello John, Thank you for the suggestions.
    Here is where I am at as of 11pm last night.
    Everything you mentioned is good except, U14 pin 2 is being pulled to ground.
    This does not happen on a known good board.
    U14 pin 2 goes to U19 pin 12 and then to U21 pin 1.
    At that point I went to bed.
    I have to work on a car this morning and later I will get back to this. >>
    Regards
    George


    7pm update.
    U21 was bad which was causing pin 2 of U14 to go to ground.
    Replaced it with a new 74LS379.
    Still 4 flashes, but now the displays show a number 7 in all 5 displays.
    Hi George,

    That is odd, normally displays do not come alive until the last flash.

    Was there any corrosion on the motherboard? I'd be checking for traces that have given up.
    John :-#)#

    --
    (Please post followups or tech inquiries to the USENET newsgroup)
    John's Jukes Ltd.
    MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
    (604)872-5757 (Pinballs, Jukes, Video Games)
    www.flippers.com
    "Old pinballers never die, they just flip out."
    No corrosion at all, that is what bothers me.
    Continuity, good everywhere I check.
    One number 7 comes up in all displays.
    Flashes 4 times then stops every time.


    A bad 7417
    --- Synchronet 3.19a-Win32 NewsLink 1.113
  • From John Robertson@spam@flippers.com to rec.games.pinball on Saturday, March 19, 2022 14:38:51
    From Newsgroup: rec.games.pinball

    On 2022/03/19 4:17 a.m., gtriley@yahoo.com wrote:
    On Saturday, March 12, 2022 at 7:01:56 AM UTC-5, gtriley@yahoo.com wrote:
    On Friday, March 11, 2022 at 1:03:27 PM UTC-5, John Robertson wrote:
    On 2022/03/03 4:11 p.m., gtr...@yahoo.com wrote:
    On Thursday, March 3, 2022 at 6:35:36 AM UTC-5, gtr...@yahoo.com wrote: >>>>> On Wednesday, March 2, 2022 at 10:05:53 AM UTC-5, John Robertson wrote: >>>>>> On 2022/03/02 4:01 a.m., gtr...@yahoo.com wrote:
    Flashes 4 times then stops. I have changed U17 and U4 as the repair guide states. I have tested continuity from all pins, I also went backward to U5 and changed that. Still, only 4 flashes. Any suggestions are appreciated.
    You need a Logic Probe or Oscilloscope at this point.

    Check inputs to U14 - pins 20 through 23 - they should all be pulsing. >>>>>>
    If good then check U14 outputs pins 14 - 17 inclusive, again they should >>>>>> be pulsing.

    If bad, check U17 pins 37 through 40 inclusive, are they all pulsing? If >>>>>> yes, then there is a connection problem between U17 and U14 pins. If no, >>>>>> then do a continuity check to ground or Vcc on those four pins - any >>>>>> shorted to ground or Vcc?

    I have a Game Plan pinball support page (added the above to) here: >>>>>>
    https://flippers.com/gameplanTips.html

    John :-#)#

    --
    Hello John, Thank you for the suggestions.
    Here is where I am at as of 11pm last night.
    Everything you mentioned is good except, U14 pin 2 is being pulled to ground.
    This does not happen on a known good board.
    U14 pin 2 goes to U19 pin 12 and then to U21 pin 1.
    At that point I went to bed.
    I have to work on a car this morning and later I will get back to this. >>>>>
    Regards
    George


    7pm update.
    U21 was bad which was causing pin 2 of U14 to go to ground.
    Replaced it with a new 74LS379.
    Still 4 flashes, but now the displays show a number 7 in all 5 displays. >>> Hi George,

    That is odd, normally displays do not come alive until the last flash.

    Was there any corrosion on the motherboard? I'd be checking for traces
    that have given up.
    John :-#)#

    --
    (Please post followups or tech inquiries to the USENET newsgroup)
    John's Jukes Ltd.
    MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
    (604)872-5757 (Pinballs, Jukes, Video Games)
    www.flippers.com
    "Old pinballers never die, they just flip out."
    No corrosion at all, that is what bothers me.
    Continuity, good everywhere I check.
    One number 7 comes up in all displays.
    Flashes 4 times then stops every time.


    A bad 7417

    Hi George,

    Is that what you found? Which 7417 (if there is more than one that is...)

    Sorry, I got busy and forgot to follow up...

    John :-#)#
    --
    (Please post followups or tech inquiries to the USENET newsgroup)
    John's Jukes Ltd.
    MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
    (604)872-5757 (Pinballs, Jukes, Video Games)
    www.flippers.com
    "Old pinballers never die, they just flip out."
    --- Synchronet 3.19a-Win32 NewsLink 1.113