(Topic ID: 257395)

PSU5 LM323K Replacement

By wombat

1 year ago


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  • 16 posts
  • 11 Pinsiders participating
  • Latest reply 1 year ago by Crash
  • Topic is favorited by 2 Pinsiders

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    #1 1 year ago

    I'm looking into changing the LM323K regulator due to heat on my WCS94 driver board. Has anyone installed the PSU5 replacement in a WPC-89 board? How did work?

    https://www.ezsbc.com/index.php/featured-products-list-home-page/psu5.html#.XfLSrvyIZzm

    #2 1 year ago

    I posted a PSU5 installed on my Party Zone last year.

    #3 1 year ago

    I installed one in my Theatre of Magic (WPC-S) but Power Driver Board is the same. 5 volt is now rock solid and no more random resets.

    2019-12-12 21.36.54 (resized).jpg
    #4 1 year ago

    Yes. It's solid. Do it.

    #5 1 year ago

    I wouldn’t.
    1. The heat isn’t an issue. That’s what the big heat sink is for.
    2. The regulator is working. Why mess with it?
    3. The ez part causes the sound board to emit a machine gun sound on power down. It’s annoying.
    4. The LM323K isn’t a significant reason for resets. Connectors cause far more resets than the LM323K.

    Chris Hibler - CARGPB #31
    Http://chrishiblerpinball.com/contact
    http://www.PinWiki.com/ - The new place for pinball repair info

    #6 1 year ago

    Shoot, i put one in my taxi. Not a drop in replacement for system 11.

    1 month later
    #7 1 year ago
    Quoted from ChrisHibler:

    I wouldn’t.
    1. The heat isn’t an issue. That’s what the big heat sink is for.
    2. The regulator is working. Why mess with it?
    3. The ez part causes the sound board to emit a machine gun sound on power down. It’s annoying.
    4. The LM323K isn’t a significant reason for resets. Connectors cause far more resets than the LM323K.

    Chris Hibler - CARGPB #31
    Http://chrishiblerpinball.com/contact
    http://www.PinWiki.com/ - The new place for pinball repair info

    1. Heat does cause damage to the boards over time and dry solder joints. It also puts more load on the 12v power supply including the connectors and board components in that chain. The waste heat is created as part of the original linear regulator's design to lower the output voltage to 5v.

    2. These regulators do cause intermittent issues. For example, I re-capped my power supply in Police Force and am still only getting 4.95v out of it. This is with no 5v loads connected. As a result the game often does not boot.

    3. Simply a personal preference vs. how good the game functions after upgrading the regulator.

    4. It is often not, but with these parts often times being over 30 years old, that statistic is changing.

    #8 1 year ago
    Quoted from Crash:

    2. These regulators do cause intermittent issues. For example, I re-capped my power supply in Police Force and am still only getting 4.95v out of it. This is with no 5v loads connected. As a result the game often does not boot.

    That minor voltage variation isn’t enough to cause resets. People always talk about low voltage but there are other factors. I have WPC boards that output 4.85VDC and they run fine in my TZ.

    Chris Hibler - CARGPB #31
    Http://chrishiblerpinball.com/contact
    http://www.PinWiki.com/ - The new place for pinball repair info

    #9 1 year ago

    If it’s stable 4.85 is fine.

    #10 1 year ago

    If it ain't broke don't fix it.

    If you're operating the game MAYBE address heat issues, but home use even with weekend parties? Nah.

    #11 1 year ago

    If you replace your low voltage regulator you also risk pulling traces/through holes and causing damage to your board unless you have the proper tools and technique. Its not an "easy" swap, FYI

    #12 1 year ago

    Output voltage characteristics of the LM323.
    4.75V under load for a LM323K is still within spec.
    Look out for voltage loss over connectors.

    LM323_OutputSpec.jpg

    #13 1 year ago

    I'm having an issue with mine in my Police Force. It doesn't seem to be switching/regulating properly and outputs way too high. Fortunately I decided to test this before connecting any of the boards. Before I swapped this the game booted once, but did not boot subsequent times. I wanted to try this and here is what I'm seeing. I have it installed with alligator leads connected to a 555 lamp.

    DSC_0013 (resized).jpg

    I'm getting this on the 5v test point:

    DSC_0012 (resized).JPG

    So I decided to check the input vs. output test points on the PSU5.

    Input:

    DSC_0016 (resized).JPG
    DSC_0017 (resized).JPG

    Output:

    DSC_0014 (resized).JPG
    DSC_0015 (resized).JPG

    I took another one of these and fed it 13.5v from my bench power supply. I hooked up the lamp and it's now getting 5v which is normal. Do I need to check something else on the power supply board, such as the regulator IC? I'm getting the same output regardlesss of if I have the lamp connected or not. Maybe I have a bad one.

    #14 1 year ago

    Nevermind, this is evidently a 2N6057 power transistor and not an LM323K regulator. My transistor got so hot the ink vaporized off and I couldn't tell what it was. That and some evidently incorrect advice I came across caused me to think it was a cross-compatible LM323K, lol. In this case I'll replace the 30 year old MC1723CP regulator IC as all the caps have been swapped.
    transistor (resized).PNG

    #15 1 year ago

    If you measure the output of the LM723 pins 4 and 5 and the measurement is equal then the regulator is fine.

    Chris Hibler - CARGPB #31
    Http://chrishiblerpinball.com/contact
    http://www.PinWiki.com/ - The new place for pinball repair info

    #16 1 year ago

    Cool, thanks for the tip.

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