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  • Low Voltage on Stern SDB-100

    From Othello@21:1/5 to All on Tue May 21 23:07:14 2024
    Novice taking a stab at troubleshooting. Stern Meteor displays are out.
    The playfield lamps are fine, the MPU boots, and games do play fine with
    no errors. Just no display.

    TP2 voltage on SDU-100 shows 85.6-87.9 Volts where there should be 185V according to schematic. RT1 does not change measured voltage. Replaced
    C23 and C26 capacitors with no improvement. TP4 shows 250V. VR1 shows
    65V where schematics says it should be 140V. So all the voltages are
    different from schematics.

    Any thoughts where the fault could be? Easier to just punt and swap in
    an Alltek board?

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From John Robertson@21:1/5 to Othello on Tue May 21 22:34:57 2024
    On 2024/05/21 8:07 p.m., Othello wrote:
    Novice taking a stab at troubleshooting. Stern Meteor displays are out.
    The playfield lamps are fine, the MPU boots, and games do play fine with
    no errors. Just no display.

    TP2 voltage on SDU-100 shows 85.6-87.9 Volts where there should be 185V according to schematic. RT1 does not change measured voltage. Replaced
    C23 and C26 capacitors with no improvement. TP4 shows 250V. VR1 shows
    65V where schematics says it should be 140V. So all the voltages are different from schematics.

    Is the voltage being measured with or without any load. My suspect is
    that the pass transistor is open - check what the voltages are on the
    driver transistor for the pass regulator


    Any thoughts where the fault could be? Easier to just punt and swap in
    an Alltek board?

    Easier? Yes, certainly easier, and the Alltek boards are very reliable -
    I've been selling them for a couple of decades now.

    https://flippers.com/catalog_oc/bally-stern-alltek-ultimate-solenoid-driver-board-ultimate-sol-drv

    However I find it more fun to fix the board - if you like troubleshooting!

    John :-#)#

    --
    (Please post followups or tech inquiries to the USENET newsgroup)
    John's Jukes Ltd.
    #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."

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Othello@21:1/5 to John Robertson on Fri May 31 10:43:10 2024
    On 5/22/2024 1:34 AM, John Robertson wrote:
    On 2024/05/21 8:07 p.m., Othello wrote:
    Novice taking a stab at troubleshooting. Stern Meteor displays are
    out. The playfield lamps are fine, the MPU boots, and games do play
    fine with no errors. Just no display.

    TP2 voltage on SDU-100 shows 85.6-87.9 Volts where there should be
    185V according to schematic. RT1 does not change measured voltage.
    Replaced C23 and C26 capacitors with no improvement. TP4 shows 250V.
    VR1 shows 65V where schematics says it should be 140V. So all the
    voltages are different from schematics.

    Is the voltage being measured with or without any load. My suspect is
    that the pass transistor is open - check what the voltages are on the
    driver transistor for the pass regulator


    Any thoughts where the fault could be? Easier to just punt and swap in
    an Alltek board?

    Easier? Yes, certainly easier, and the Alltek boards are very reliable -
    I've been selling them for a couple of decades now.

    https://flippers.com/catalog_oc/bally-stern-alltek-ultimate-solenoid-driver-board-ultimate-sol-drv

    However I find it more fun to fix the board - if you like troubleshooting!

    John :-#)#

    Indeed it was!

    Your tip to look at the pass transistor combined with the
    troubleshooting videos on YouTube (like Joe's Classic Video Games
    channel) led me to Q23. On closer inspection the transistor can had a
    puffy ring of what looked like insulator foam around the base.
    Definitely blown. The replacement arrived just today. I popped that bad
    boy out and installed the new one, and lo and behold, the display
    started to work!

    That success is making me feel bolder and more confident. Now I can
    tackle my next project, a Bally Spectrum. That one has some stuck drop
    targets and a worn out playfield but the biggest problem is that
    intermittently all solenoids lose power at game start. No kickers, no
    bumpers, no flippers. But they often come back if I power cycle the
    game. All sounds, lights and displays work.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Tony@21:1/5 to John Robertson on Thu Aug 15 16:16:49 2024
    John Robertson wrote:
    On 2024/05/21 8:07 p.m., Othello wrote:
    Novice taking a stab at troubleshooting. Stern Meteor displays are
    out. The playfield lamps are fine, the MPU boots, and games do play
    fine with no errors. Just no display.

    TP2 voltage on SDU-100 shows 85.6-87.9 Volts where there should be
    185V according to schematic. RT1 does not change measured voltage.
    Replaced C23 and C26 capacitors with no improvement. TP4 shows 250V.
    VR1 shows 65V where schematics says it should be 140V. So all the
    voltages are different from schematics.

    Is the voltage being measured with or without any load. My suspect is
    that the pass transistor is open - check what the voltages are on the
    driver transistor for the pass regulator


    Any thoughts where the fault could be? Easier to just punt and swap in
    an Alltek board?

    Easier? Yes, certainly easier, and the Alltek boards are very reliable -
    I've been selling them for a couple of decades now.

    https://flippers.com/catalog_oc/bally-stern-alltek-ultimate-solenoid-driver-board-ultimate-sol-drv


    However I find it more fun to fix the board - if you like troubleshooting!

    John :-#)#



    If it wasn't for me busting every pinball machine this newsgroup,
    probably wouldn't exist.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From John Robertson@21:1/5 to Tony on Thu Aug 15 17:25:54 2024
    On 2024-08-15 1:16 p.m., Tony wrote:
    John Robertson wrote:
    On 2024/05/21 8:07 p.m., Othello wrote:
    Novice taking a stab at troubleshooting. Stern Meteor displays are
    out. The playfield lamps are fine, the MPU boots, and games do play
    fine with no errors. Just no display.

    TP2 voltage on SDU-100 shows 85.6-87.9 Volts where there should be
    185V according to schematic. RT1 does not change measured voltage.
    Replaced C23 and C26 capacitors with no improvement. TP4 shows 250V.
    VR1 shows 65V where schematics says it should be 140V. So all the
    voltages are different from schematics.

    Is the voltage being measured with or without any load. My suspect is
    that the pass transistor is open - check what the voltages are on the
    driver transistor for the pass regulator


    Any thoughts where the fault could be? Easier to just punt and swap
    in an Alltek board?

    Easier? Yes, certainly easier, and the Alltek boards are very reliable
    - I've been selling them for a couple of decades now.

    https://flippers.com/catalog_oc/bally-stern-alltek-ultimate-solenoid-
    driver-board-ultimate-sol-drv

    However I find it more fun to fix the board - if you like
    troubleshooting!

    John :-#)#



    If it wasn't for me busting every pinball machine this newsgroup,
    probably wouldn't exist.

    Perhaps...

    John ;-#)#

    --
    (Please post followups or tech inquiries to the USENET newsgroup)
    John's Jukes Ltd.
    #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."

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)