Studio Color 575 - LogicBoard issue

One of my studio color 575 has a problem with the logic board. The board seems to have no power, the display and motors are dead, but the LEDs for DMX and Lamp status are working. I replaced the whole power supply but the problem is the same. Should I replace the whole logic board? I can not believe its damaged, because the LEDs are still working..
  • Update:

    I replaced the whole logic board. Now its all ok. That implies that the defective component is on the logicboard. As it is a very expensive unit I want to ask if anyone has an idea what component on the board could be the faulty one.

    LEDs are working fine but the display is dead and the motors are without power.

    (Excuse eventually bad english)
  • U13 is a regulator that pretty much provides all logic power to the board . . . only the motor power goes around it, and with no logic to the motor drivers, they will be limp as well. A global failure as you describe is likely something that simple . . . and with the schematics being available on the HES site, it should be a simple matter of metering regulator input and output to see if this is the issue, and for someone with decent PCB soldering/rework skills, a pretty trivial item to replace.

    If all else fails, LightParts should be able to repair the board at a far lower cost than replacement if that is all that has failed.

    - Tim
  • It seemed to be that one of those logic gates doesn switch through. I had a look an the shematics and my first guess was on U13 because it is the first logic gate in the circuit. Anyway. I´ve sent the logic board to our local support here in Germany. I ve done much of repair on the StudioColors by myself, but the logic board is a bit to high for me.. ^^

    Thank you for help anyway.

    Sebastian
  • U13 isn't a gate - it's a voltage regulator. Correct terminology will make helping you a heck of a lot easier . . .

    - Tim
  • You were right. U13 was the faulty component. Now, another washlight has the same problem. On the schematic there is the regulator LM2596 but on the board there is the following regulator: LM2576 HVS 5.0 Do you think this could be the problem or do you think it doesnt matter which of them is on the board?

    The difference between these two units is: The LM2596 regulates between 7 - 40 V and the other one between 4,75 - 60 V
  • [QUOTE=Sille;50620]You were right. U13 was the faulty component. Now, another washlight has the same problem. On the schematic there is the regulator LM2596 but on the board there is the following regulator: LM2576 HVS 5.0 Do you think this could be the problem or do you think it doesnt matter which of them is on the board?

    The difference between these two units is: The LM2596 regulates between 7 - 40 V and the other one between 4,75 - 60 V

    Are they the same exact board? The Studio Color 575 schematic shows the LM2596 regulator, and the Studio Color M/S schematic shows the LM2576 HVS. Considering that the circuit is pretty much identical, I would wager that they are equivalent. Looking at the specs, they are both 3amp 5volt switching regulators, with the difference being that the 2576 is a 52KHz switch frequency device, and the 2596 is a 152KHz switcher . . . probably a bit more efficient due to the higher freq. The 2596 schematic has a smaller filter inductor as well, owing to the higher frequency . . .

    Bottom line is, that depending on the age, either is correct - I would replace with what is there, myself.

    Have you been having problems with noisy/spiky input power? I would not think that these regulators are normally a high failure part, unless they are getting dirty input . . . might just be chance, though, since these sit behind the motor power supplies . . .

    Once other thing, has anyone been doing a lot of movement of heads/etc. with the power off? The motors can generate power back into the circuitry, which can also be detrimental . . .

    - Tim
  • It happens by switching them on. There is a ground fault interupter on the power distribution that I use to switch all fixtures on. The supplied voltage is o.k . and it worked for a long time. I wonder why the fuse on the switching power supply of the SCol wasnt blown, when there was faulty voltage.

    I replaced many stepper motors in every fixture because they stucked and there was iron powder in it. Maybe there is a relation to the new fault.

    I will try to get new regulators - maybe they are just too old. The fixtures have 15 years of age.

    Thanx in advance
    I will report when I managed to fix it

    -Sebastian
  • It´s like a curse - On the second board there is another failure. Its the quartz crystal oscillator (X1). I think its for the CPU frequency. It seems to be not soldered but attached with silicone. Maybe its a heat sensitive unit. Am I right? Why does it fail by switching the fixtures on?

    What should I take care of, when I want to replace this item? :dunno:
  • I *MUST* be soldered, or it won't work . . . so if it is loose, then you found the problem, and it is mechanical. If the leads remain, resolder it . . . Crystals can be shock sensitive, so likely it was left up on longer leads and stabilized with silicone to help protect it.

    What makes you think it is bad?

    Oh, and based on the schematic, X1 is just a crystal - not a full oscillator . . . 32.788 KHz.

    - Tim
  • I contacted the support here in Germany and as I sent them the first board, they replaced the crystal, too. They told me to replace the crystal on the other board, that had exactly the same failure.
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