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Thread: RA82 spinup troubles

  1. #1
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    Default RA82 spinup troubles

    So I located a circuit in the house which is used the least and plugged the drive in. Flipped the breaker and was greeted by fans spinning up and no nasty noises or magic smoke. Good.
    Next I took a piece of wire and jumpered the 6 o-clock and 9 o-clock pins together in the SEQ IN port so it would be allowed to spin up, unlocked the heads, and started the spinup.
    The lights in the house dimmed, the motor and drive started to spin up, but then it kicks out and lights the fault lamp.
    Hmm, okay. So either something is wrong or the motor is overloading. I'm not quite sure.
    Tried two more times, same deal.
    I checked waht a single fault light meant according to this and there is nothing attributed to just the fault lamp. I can't check the bulbs either. I don't know how to remove them.
    Huh. Bizarre, and worrying. :/
    Last edited by NeXT; February 4th, 2011 at 06:19 PM.
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  2. #2
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    Default

    I suppose the first thing that could help us is if you took a video with sound, with the hood up of the spinup process. Start with the fans running, before pressing run. Then announce and press run, let us hear the sounds, and in particular how long the motor runs until the fault comes. That delay time can be helpful in determining the problem.

    There is a belt that runs from the motor to the HDA. Does the disk indeed start to spin up? That belt can be tensioned and maybe the tension needs to be adjusted (belt slipping and disk not coming up to speed fast enough). Belt adjustment is covered in the RA81 service manual on bitsavers. I'm pretty sure that this is the same across RA80/82/82.

    Also, the disk motor is a capacitor start motor. In the RA80, the capacitor was not switched by a mechanical centrifugal switch (as with most machine tool motors), it was controlled by the drive controller. Ultimately, the spin-up problem in my RA80 was a bad output pin on an I/O expander that drove the drivers that closed the start capacitor relay. I highly doubt that anyone else would have this problem, but I just mention the capacitor start so that you know to listen for the start capacitor relay to cut out.

    The RA82 should have some pretty advanced diagnostics. The RA80 has on board lights and switches and EXTENSIVE interactive on-board diagnostics. ISTR that RA81 and RA82 have a port to connect a 300 baud RS232 terminal so that you can interact with the drive controller directly. The DB25 connector may be up by the motor start capacitor on the right side of the controller when facing the drive from the front.

    Get the RA81 service manual (EK-0RA81-SV-001) from bitsavers and look at chapter 4.

    The manual will also tell you how to service the lamps. I use needle nose pliers to carefully grab the glass envelope and slide them out, but I think the right tool is actually a piece of rubber tubing. Jameco still sells the bulbs.

    Lou

  3. #3
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    I gave up trying to get my RA82 to do anything. I couldn't even get anything from the diagnostic serial port. It would be nice to see it spin up and in operation at least once, but the reality is even if it worked I probably would almost never use it.

    If you can't get anywhere getting your RA82 up and running you might have an easier time getting your 11/84 UDA50 up and running with an RA70. I'll have to see if I have any working RA70 drives I could spare. I connected one to a 4000-700A and spun it up last night just for fun.

    -Glen

  4. #4
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    I wish I lived a little closer to you guys to help you out with the troubleshooting / repairs of your drives. I really enjoy the repair aspect. Most of what I get is broken and so since my expectations are low to start with, I'm usually not disappointed.

    Glenn, if very little is working, I would suspect a power supply problem on your RA8x drive.

    All that said, the RA7x drives are compact and seem pretty reliable. I have an RA72 on an 11/73 that works fine.

    Lou

  5. #5
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    Because of no sound insulation, I can't run the drive when I get home from work because by then it's quite late.
    I'll try and get the video up this afternoon after the laundry has finished.
    I'm hopeful that the this isn't too big of an issue as it seems like the drive was very recently pulled out of active service and has not even had a month yet to sit in storage. I'm assuming it's just very cranky.
    [Need something to waste time on? Click here to visit my YouTube channel CelGenStudios]
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  6. #6
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    The video just got thrown up on Youtube.

    http://www.youtube.com/watch?v=bHVtAbxZ-7w

    I'm hoping you can hear the motor trying to spin up. I can't use my microphone as my roommates seem to always be either watching TV, doing stuff on youtube, or playing music all day long.
    Anyways, that aside, here you go for a quick in-a-nutshell video.
    [Need something to waste time on? Click here to visit my YouTube channel CelGenStudios]
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  7. #7

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    I did not hear the telltale sounds of a disk spinning up. It's a very distinctive sound, as I had an RA80 (or was it an RA81)
    that Lou now has. It might normally take 20 seconds or so to fully come up to speed, so the fault light going on after just
    a few seconds implies something is wrong. I don't know enough about these old drives to say much more. Hopefully it might
    be a slipping belt like someone suggested.

  8. #8
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    Let me put up a second quick video that shows it it IS at least turning the motor.
    I could not put them in one video because Premier is deciding not to play nice at all with MOV files. :/

    Edit: http://www.youtube.com/watch?v=0qhHzuBKLoA
    [Need something to waste time on? Click here to visit my YouTube channel CelGenStudios]
    --------------------------------------------------------------------------------------------
    [No time for videos? Click here to visit my Twitter feed @CelGenStudios]

    = Excellent space heater

  9. #9
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    It looks like the brake disengages and the motor starts to spin. However, it doesn't spin for long at all. Nowhere near long enough to get up to operating speed.

    My first thought is that the sector pickup is dirty or has some problem. It would be the first indication to the drive that the disk is not spinning when it should be.

    However, let's not get ahead of ourselves. Get the RA81 service manual off bitsavers, and start learning how to be more interactive with the diagnostic port. I may start doing that myself this evening.

    Lou

  10. #10
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    They have a manual specifically for the RA82. It looks like if the system is not seeing the disc spinning, either the speed transducer is acting up or the cabling to it is.
    Also, what would be the signs of the brake not fully disengaging? It's possible that since it's of the friction variety it might be still on and it's overloading the motor.
    [Need something to waste time on? Click here to visit my YouTube channel CelGenStudios]
    --------------------------------------------------------------------------------------------
    [No time for videos? Click here to visit my Twitter feed @CelGenStudios]

    = Excellent space heater

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