DEC 3000/800 AXP boot problem - DEC

This is a discussion on DEC 3000/800 AXP boot problem - DEC ; Hi, just a quick enquiry. I have aquired a DEC 3000 Model 800 AXP and have a boot problem. The system was booting about once every ten power ups. The status LEDs don't move in the case where the system ...

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Thread: DEC 3000/800 AXP boot problem

  1. DEC 3000/800 AXP boot problem

    Hi, just a quick enquiry.

    I have aquired a DEC 3000 Model 800 AXP and have a boot problem. The
    system was booting about once every ten power ups. The status LEDs
    don't move in the case where the system checks do not 'kick in', they
    remain on '00'. I have cleaned the entire box and used contact cleaner
    on all connections, and re-seated the motherboard and IO module.

    Previously when the system did 'kick in' all tests completed correctly
    except the keyboard/mouse test. I am using a VT520 connected via an
    original DECconnect cable. I managed to install both OpenVMS 6.1 (the
    original disk received with the unit) and OpenVMS 8.3 (although this
    didn't boot, but probably due to the fact that I selected DECnet but
    don't have any thick/thin cables connected).

    Sorry to be so long winded. So the question is, apart from reseating/
    cleaning cables/connections, is there anything else I could check/test/
    try? I have enough competence to measure voltages and possibly even
    power ripples and the like, but I don't have a logic analyser.

    Do the SROMs age at all? It is a standard x512 EEPROM. It has a
    sticker over the programming window (assuming it has one). Is there a
    battery backed module that could be causing intermittent problems?

    Thanks for any pointers,

    Mark.


  2. Re: DEC 3000/800 AXP boot problem

    Forgot to add.. my talking of correct booting was in the past tense -
    in the last few attempts I have got the following errors - 48 (mouse)
    and EE (power up before console). I am assuming that these are because
    I tried the S3 switch in both orientations, and in this case it wasn't
    in the 'alternate console' position.

    Thanks, Mark.


  3. Re: DEC 3000/800 AXP boot problem

    Additional information:

    I intermittently get the following error:

    ASIC ?? 002 0020

    T-ERR-ASIC COREIO
    address = f0080280
    data read = 0
    data exp = aaaaaa

    Code 'EF' is displayed on the LEDs.

    Does this, and the 'not booting at all' indicate a problem with the
    SROM/EEPROM? I flashed it recently to version 7.0, the latest, but I
    think it was having this problem before it was flashed.

    Thanks, Mark.


  4. Re: DEC 3000/800 AXP boot problem

    In article <1188245969.103108.116750@w3g2000hsg.googlegroups.c om>, urbancamo writes:
    >
    > ASIC ?? 002 0020
    >
    > T-ERR-ASIC COREIO
    > address = f0080280
    > data read = 0
    > data exp = aaaaaa
    >


    For what little I know at this level I think you are lucky this
    system boots occaisionally. This looks like a pretty basic failure.

    You might try reloading the latest firmware, but you also would take
    the risk that the firmware load would fail.

    IMHO its time to get this fixed if it's a production system, but I
    think its not, in which case its time to peruse Ebay or other
    favorite vendor.


  5. Re: DEC 3000/800 AXP boot problem


    Bob Koehler wrote:

    > In article <1188245969.103108.116750@w3g2000hsg.googlegroups.c om>, urbancamo writes:
    > >
    > > ASIC ?? 002 0020
    > >
    > > T-ERR-ASIC COREIO
    > > address = f0080280
    > > data read = 0
    > > data exp = aaaaaa
    > >

    >
    > For what little I know at this level I think you are lucky this
    > system boots occaisionally. This looks like a pretty basic failure.
    >
    > You might try reloading the latest firmware, but you also would take
    > the risk that the firmware load would fail.
    >
    > IMHO its time to get this fixed if it's a production system, but I
    > think its not, in which case its time to peruse Ebay or other
    > favorite vendor.


    Bob, thanks for the reply. The main problem is the hang on initial
    boot - where the status leds just stick on '00' and don't start their
    countdown. The service manual does not suggest anything that might
    cause this. I've noticed that the system is happier booting from cold
    rather than after a power cycle. Clearly the two scenarios (hang and
    getting the ASIC error) could be related.

    Even though this system only cost me 5 GBP I would love to get it
    running purely because it is such an astounding piece of
    engineering.
    All the fans are shock mounted, the hard drive is also shock
    mounted,
    when you open the motherboard side of the case there are literally
    *no* cables whatsoever, the power supply simply slots out (after
    removing power cables) and apart from the SCSI cables there are a
    couple of short power cables and that is it. A work of art I would
    have said!


  6. Re: DEC 3000/800 AXP boot problem

    On Aug 27, 1:01 pm, urbancamo wrote:
    > Hi, just a quick enquiry.
    >
    > I have aquired a DEC 3000 Model 800 AXP and have a boot problem. The
    > system was booting about once every ten power ups. The status LEDs
    > don't move in the case where the system checks do not 'kick in', they
    > remain on '00'. I have cleaned the entire box and usedcontact cleaner
    > on all connections, and re-seated the motherboard and IO module.
    >
    > Previously when the system did 'kick in' all tests completed correctly
    > except the keyboard/mouse test. I am using a VT520 connected via an
    > original DECconnect cable. I managed to install both OpenVMS 6.1 (the
    > original disk received with the unit) and OpenVMS 8.3 (although this
    > didn't boot, but probably due to the fact that I selected DECnet but
    > don't have any thick/thin cables connected).
    >
    > Sorry to be so long winded. So the question is, apart from reseating/
    > cleaning cables/connections, is there anything else I could check/test/
    > try? I have enough competence to measure voltages and possibly even
    > power ripples and the like, but I don't have a logic analyser.
    >
    > Do the SROMs age at all? It is a standard x512 EEPROM. It has a
    > sticker over the programming window (assuming it has one). Is there a
    > battery backed module that could be causing intermittent problems?
    >
    > Thanks for any pointers,
    >
    > Mark.


    Some generic contact cleaners just remove dust, dirt and grease - but
    do not remove oxidation (resistive oxides) and improve the
    connection. Try using some DeoxIT - if it is a connection issue, this
    will definitely fix it. I had similar issues with a few computers.
    DeoxIT is available at RadioShack, Fry's and other retail stores -
    link to their webstive for places and info: http://store.caig.com/s.nl/sc.15/category.295/.f
    You can use DeoxIT for thousands of uses - great for audio/video
    stuff.
    Mike


  7. Re: DEC 3000/800 AXP boot problem


    shaq wrote:

    > Some generic contact cleaners just remove dust, dirt and grease - but
    > do not remove oxidation (resistive oxides) and improve the
    > connection. Try using some DeoxIT - if it is a connection issue, this
    > will definitely fix it. I had similar issues with a few computers.
    > DeoxIT is available at RadioShack, Fry's and other retail stores -
    > link to their webstive for places and info: http://store.caig.com/s.nl/sc.15/category.295/.f
    > You can use DeoxIT for thousands of uses - great for audio/video
    > stuff.
    > Mike


    Mike. Thanks for the tip - I will try and source some in the UK.

    Mark.


  8. Re: DEC 3000/800 AXP boot problem

    In article <1188308388.735021.300420@19g2000hsx.googlegroups.c om>, urbancamo writes:
    >
    > Bob, thanks for the reply. The main problem is the hang on initial
    > boot - where the status leds just stick on '00' and don't start their
    > countdown. The service manual does not suggest anything that might
    > cause this. I've noticed that the system is happier booting from cold
    > rather than after a power cycle. Clearly the two scenarios (hang and
    > getting the ASIC error) could be related.


    Once upon a time I had a disk drive (in a PC) which would fail in
    a few minutes. Finding one of the large diodes quite a bit hotter
    than the other I used my finger as a heat sink the next time I
    powered it up and kept it going for much longer.

    I don't recommend finger heat sinks for most applications, but you
    indicate cold seem to work better. Run your fingers around inside
    after a failure (carefully) and see if you can find some component
    that could use more cooling than originally designed.

    >
    > Even though this system only cost me 5 GBP I would love to get it
    > running purely because it is such an astounding piece of
    > engineering.
    > All the fans are shock mounted, the hard drive is also shock
    > mounted,
    > when you open the motherboard side of the case there are literally
    > *no* cables whatsoever, the power supply simply slots out (after
    > removing power cables) and apart from the SCSI cables there are a
    > couple of short power cables and that is it. A work of art I would
    > have said!


    I never had an 800, but the DEC 3000 I have and have had were no
    works of art inside.


  9. Re: DEC 3000/800 AXP boot problem


    Bob Koehler wrote:

    > > getting the ASIC error) could be related.


    I found problem causing the ASIC error - there is a post-manufacturing
    hack on the IO module that involves two pins of a PLCC being lifted
    from their pads and soldered to a diode and resister in parallel. The
    other end is soldered via a wire to a pad on the motherboard. The glue
    holding the hack to the top of the PLCC has long since deteriorated
    and one of the pins was very close to its' neighbour and pad. I moved
    this clear and since then a couple of boots have now shown the error.

    What I'm noticing now however is that the system is hanging
    intermittently. My focus now is on the power supply. I have heard that
    capacitors can deteriorate in a power supply - and have personal
    experience of old capacitors blowing up. What could I check on the
    power supply to determine if that is the problem?

    > I don't recommend finger heat sinks for most applications, but you
    > indicate cold seem to work better. Run your fingers around inside
    > after a failure (carefully) and see if you can find some component
    > that could use more cooling than originally designed.


    I will do this on the mainboard, although if the problem is in the
    power supply then that could be tricky!

    Mark.


  10. Re: DEC 3000/800 AXP boot problem

    > and one of the pins was very close to its' neighbour and pad. I moved
    > this clear and since then a couple of boots have now shown the error.


    That should say 'NOT shown the error'


  11. Re: DEC 3000/800 AXP boot problem

    I put the PSU back together as is and I got the scope on the '800 this
    evening.

    Findings:

    1. The 5V line is running at 5.15V
    2. The 3.45V line is running at 3.45V
    3. The ripple on both 5V and 3.45V lines is approx. 5mv at about 30
    KHz

    I've attached the oscilloscope and meter images (nice to have a PC
    based scope!)

    Observations:

    Both 5V and 3.45V lines appear to be pretty well DC regulated.
    I wouldn't have thought that 5mv of a.c. ripple would cause any
    serious problems.
    I did a finger test on the 3.45v regulator components and couldn't
    find anything 'hot' - the large heatsink to which the regulators is
    attached gets slightly warm
    I did a finger test on the CPU heatsink and the surrounding large
    PLCCs and these get hot - almost too hot to touch.

    Conclusions:

    Maybe the fans are worn and not pulling the air through the box quick
    enough. As I mentioned, they spin up quite high and then settle down
    to a low tick over.

    Maybe the fan regulation isn't working correctly - I've not noticed
    the fans speed up once the box has been on for a while. I'm not sure
    where I would look for a temperature sensor. I can ask on the groups
    and see if anyone knows, but it'll probably be up to me to find out.
    One obvious place would be under the main CPU - do you think this
    would be integrated into the main board layout and then come out to
    one of the PSU connectors.

    I can measure the voltage on the fan circuit and quite possibly trace
    the connection back to the PSU and see if I can work out how it is
    regulated. It might be regulated on power load instead? Temperature
    would seem more sensible however.

    I noticed that with the lid off the box it did seem to be quite stable
    - I didn't really have long enough to come to any firm conclusions. I
    guess running it with a desk fan pointing at the main circuit board
    for a while might give an idea.

    What do you recon? The 5V line is a little high but I wouldn't have
    thought that in itself would cause a problem. The PSU is rated at 750W
    so it may be that fully loaded the 5V line would dip to 5V from 5.15V.

    Cheers for the help,

    Mark.


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