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  1. #41
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    I have a 2004 one of these that I still use daily. The only problem I have ever had was a board went out. I don't know what is wrong with it but I still have it. If you could use it it's yours for the shipping. I think I got a solid red signal or something. I probably took notes and they are with it. If interested I could dig it out and take a look.

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    Quote Originally Posted by DavidScott View Post
    I have a 2004 one of these that I still use daily. The only problem I have ever had was a board went out. I don't know what is wrong with it but I still have it. If you could use it it's yours for the shipping. I think I got a solid red signal or something. I probably took notes and they are with it. If interested I could dig it out and take a look.
    Yes please, I'll send you a message

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    Here is a photo of what I have. My only note is "solid red light". I simply replaced it with a new one and took real good care of the old just in case I needed it later on.

    board.jpg

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    Yes. poking about with a conductive item can change bits on lines and send it off into the weeds. But the unit SHOULD be set up to withstand that. There were old app notes from various manufacturers which had techniques for handling that, such that a micro would run error free with an icnition slark and wires right next to the board, which it would not before. Things like adding "traps" to the code, that send the processor back to a known good entry point, and the like.

    That gets harder to do when programming in a higher level language, and can be less easy with a DSP. I;ve only done it with assembler, years ago, but it works. I would expect they did that, but.



    Quote Originally Posted by thermite View Post
    ....

    So long as the leads themselves do not become resonators nor transmission lines, electrons don't much care if the blankets they share are in the same bedroom, let-alone same bed.
    And there is the problem.

    The good part is that the motor run caps often are not that great to begin with.... so a bit extra may not hurt too badly.

    The bad thing is that a number of the type are now being made as metallized foil, with the ends "sputter metallized" to make the connection. That's a coating of metal applied that shorts the "coils" of wound up electrode together for one of the two plates at one end, and the other plate at the opposite end. That makes a very significantly lower inductance and resistance part, with better high frequency performance... so long leads make more difference.

    Modifying an already packaged and assembled product has it's problems.

  6. #45
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    Just in case we don't all have these, here are two links to documents that I believe are related to the dpc-A10

    OPERATION & INSTALLATION MANUAL
    http://www.linghunt.com/ForumPosts/D...011%20V1.3.pdf

    Phase Perfect DPC model Trouble shooting guide
    https://www.linghunt.com/ForumPosts/...%20Rev%20A.pdf

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    Quote Originally Posted by RustySparks View Post
    Just in case we don't all have these, here are two links to documents that I believe are related to the dpc-A10

    LINGHUNT ERROR PAGE

    https://www.linghunt.com/ForumPosts/...%20Rev%20A.pdf
    First link is dead. Second one I have in paper form but never found it on the interweby. Thanks! Saved it in pdf form now.

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    Quote Originally Posted by Hardplates View Post
    First link is dead. Second one I have in paper form but never found it on the interweby. Thanks! Saved it in pdf form now.
    Fixed the link ..

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    This gets me to thinking I should maybe check my capacitors, after all, it's been over 15 years now with near-constant use.

    Thanks for the links, the second one is new to me.

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    Quote Originally Posted by JST View Post
    That gets harder to do when programming in a higher level language, and can be less easy with a DSP. I;ve only done it with assembler, years ago, but it works. I would expect they did that, but.
    It wasn't THAT hard to work in machine-code, even when, for example, it took, IIRC, 53 settings of paddle switches in Octal to single-step enough code into a GA-SPC-12 to teach it to understand an ASR-33's paper tape reader. Because once THAT was done, all manner of code on various stored lengths of paper tape went in more rapidly. Main clock ran at the bitchin' blazing rate of all of 600 KHz, yes "Kilo".

    Our first pre-production Data General NOVA, and miracle of miracles? Not ONLY had they cracked the holy grail of a 1 MHz clock rate barrier (skew had been a problem..) the bootstrap loader for paper tape was already on-board in something rather puzzlingly named "solid-state MEMORY"!

    Mind, we still had high regard for Wang's best mag core, as "solid" enough, as we could cram 8 Kilobytes of it onto a "fat" machine if there was money enough.

    Yes, that was "kilo" bytes.



    Fast-forward to where the host one is handling a DSP or PLA with is a modern workstation with a Brazillion times the power of the target, fast I/O, sophisticated devel & debug tools, and life ain't all that hard atall.

    More interesting brain work, less tedious Octal paddle switches. Well damn.. memories.. those had, in turn, beaten diode plugboards and hollow-state bistable multivibrators all to Hell the prior generation, too.

    AN/FSQ-7 had more than one or two of them hollow-state thingies. Around 60,000, or so sucking 3 megawatts, actually. Had its own lake for a cooling pond adjacent the blockhouse.

    Now..what use was a hardened blockhouse with concrete a significant fraction of a mile thick, if even a near-miss nuke took out the damned cooling pond, we thankfully never had to find out.
    You'd have to know government thinking, or lack-thereof to understand only an impertinent PFC (guilty as charged, McGuire AFB. NYADS. SAGE. 1965) would even raise the question as to:
    "WTF happens to the Whirlwind II if the cooling water is all blowed away?"?

    You might more easily guess why I'm up for passing the baton to a younger generation?

    I recall sniggering when Steve Ciarcia said his favorite programming language was "solder".
    Elitist "modernist" bastid as I am, my favorite programming language had been a wire-wrap tool!

    Then forth.

    Older the Dinosaur, the slower the foot-race, yah?




    And there is the problem.

    The good part is that the motor run caps often are not that great to begin with.... so a bit extra may not hurt too badly.

    The bad thing is that a number of the type are now being made as metallized foil, with the ends "sputter metallized" to make the connection. That's a coating of metal applied that shorts the "coils" of wound up electrode together for one of the two plates at one end, and the other plate at the opposite end. That makes a very significantly lower inductance and resistance part, with better high frequency performance... so long leads make more difference.

    Modifying an already packaged and assembled product has it's problems.
    Yah, but..... most of the work IS already done, after all. We KNOW it is meant to deal at frequencies that do not exceed mid-range AUDIO band, so with modern scopes and various Hell-box treasures, finding and treating unwanted oscillation etc. is not even close to "new technology".

    PM has a wealth of expertise as can be tapped for support.

    What we have missed isn't more active minds on theory.
    It has been more active hands on actual hardware.

    Got some stuff to do so I can clear a hole for a road-trip up Harrispurge Pennsyltucky way. Former Virginia spin-off. Like most of the rest of the USA.

    You'd have to grok "Old Dominion".

    Somebody has to take the blame, yah?

    Laters...

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    Looking again at your You Tube percussive maintenance video:
    "You Tube"
    Quote Originally Posted by Hardplates View Post
    Now to try and find a mechanical fault such as a trace...….
    Don't think you need to concentrate on finding the mechanical fault first unless it gets much worse. Instead assume that the system operates normally if you don't whack it or twist the board. If the LEDs on the board correspond to the front panel status LEDs it would seem that when you don't whack it, it thinks that there is an overload; from the installation guide:
    >Flashing Green & Yellow, Output current too high -Short between T3 & T1 or T2 (Excessive load)<
    this seems to get back to a Hall sensor fault, as you originally suspected.
    When you do whack it, instead it thinks there is a problem with the IGBT or drivers; from the troubleshooting guide:
    >The bottom line with a flashing RED LED is that there is a problem with either the IGBT or the drivers of the IGBT on the control board.<
    Which could indicate a soldering problem associated with driver replacement.
    Just proceed as if there was no mechanical fault until you discover the cause of what you get without whacking it first, then look at the other problem if necessary. Or at least that is what I would do..

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    Quote Originally Posted by RustySparks View Post
    Looking again at your You Tube percussive maintenance video:
    "You Tube"


    Don't think you need to concentrate on finding the mechanical fault first unless it gets much worse. Instead assume that the system operates normally if you don't whack it or twist the board. If the LEDs on the board correspond to the front panel status LEDs it would seem that when you don't whack it, it thinks that there is an overload; from the installation guide:
    >Flashing Green & Yellow, Output current too high -Short between T3 & T1 or T2 (Excessive load)<
    this seems to get back to a Hall sensor fault, as you originally suspected.
    When you do whack it, instead it thinks there is a problem with the IGBT or drivers; from the troubleshooting guide:
    >The bottom line with a flashing RED LED is that there is a problem with either the IGBT or the drivers of the IGBT on the control board.<
    Which could indicate a soldering problem associated with driver replacement.
    Just proceed as if there was no mechanical fault until you discover the cause of what you get without whacking it first, then look at the other problem if necessary. Or at least that is what I would do..

    I will have a board with a good current sensor next week so I can "borrow" one from that to see if it fixes anything. The only thing that got me with the instructions is under that light sequence it say operates normally under no load.


    I will definitely be digging much deeper and going to see if I can start collecting broken complete units, boards and parts. Exploration and repair will not end when my unit is fixed. It will be interesting to see if they share a common failure mode.

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    Quote Originally Posted by Hardplates View Post
    The only thing that got me with the instructions is under that light sequence it say operates normally under no load.
    Yes that is confusing, because in your case it doesn't operate even with no load, but the actual indication would be the same either way. In case(1): No problem with Phase Perfect, but you have too much load externally, or case(2) Problem with Phase Perfect that causes it to THINK you have too much load externally, the indication is the same.

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    Another good rule when fixing things is "fix what you know is wrong"... even if you "know" that "it can't possibly be the problem"..... (in theory, anyway).

    The place for the "theory" is to foresee what may happen and plan what to do to fix/avoid/etc problems that may come up. Being prepared.

    And, the same, to see what MAY have happened, and use those probabilities to help fix/etc what HAS happened.

    With the knowledge that nearly every problem turns out to be something you did not anticipate. But the theory helps to keep things on track a bit, as to what MAY happen or have happened, so you remember to look for that.

    The switching frequency in the PP seems to be high enough to avoid an audible noise issue, which means the first 5 or 10 harmonics are actually going to get up fairly high, definitely into what bats would consider mid to high "bat audio" range.... That;'s already in an area where old school motor run are starting to have issues, and any significant extra wire length is likely to be noticed. Been there, seen that, printed my own T shirt. Later had to "eddicate" some new engineers on why what they were doing was having the opposite effect to what they expected, it was the wire length, and that was at really near-audio frequencies...... They had "calculated" that it "could not be an issue".

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    Quote Originally Posted by JST View Post
    Another good rule when fixing things is "fix what you know is wrong"... even if you "know" that "it can't possibly be the problem"..... (in theory, anyway).

    The place for the "theory" is to foresee what may happen and plan what to do to fix/avoid/etc problems that may come up. Being prepared.

    And, the same, to see what MAY have happened, and use those probabilities to help fix/etc what HAS happened.

    With the knowledge that nearly every problem turns out to be something you did not anticipate. But the theory helps to keep things on track a bit, as to what MAY happen or have happened, so you remember to look for that.

    The switching frequency in the PP seems to be high enough to avoid an audible noise issue, which means the first 5 or 10 harmonics are actually going to get up fairly high, definitely into what bats would consider mid to high "bat audio" range.... That;'s already in an area where old school motor run are starting to have issues, and any significant extra wire length is likely to be noticed. Been there, seen that, printed my own T shirt. Later had to "eddicate" some new engineers on why what they were doing was having the opposite effect to what they expected, it was the wire length, and that was at really near-audio frequencies...... They had "calculated" that it "could not be an issue".
    I agree especially in this situation since it's difficult to "know" something is not related to the main issue when I don't yet "know" or fully understand how the board operates. This is going to be a long slow process but I am grateful to the PM communities generosity and willingness to help. Slowly we can compile data on these units to aid in maintenance and repair.

    Being my last weekend before I begin juggling classes and running the shop at the same time I decided to volunteer this weekend to helping my father complete some projects like machining a mount to mount a red dot optic on his doppler radar and installing a solar setup with a fan at his shooting bench. I felt is was best to take a short break and wait for the other board and other unit to arrive in the hopes it will give me an advantage. It's also important to keep "Paa" comfortable while hes shooting.

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    Quote Originally Posted by Hardplates View Post
    ... it's difficult to "know" something is not related to the main issue when I don't yet "know" or fully understand how the board operates. .....
    And this is the single largest impediment to getting one of these repaired. There is no available, comprehensive schematic for these. Troubleshooting electronics
    is nearly impossible with a schematic. One that hopefully includes pinouts, waveforms at various places. Now we're all adults in the room and we all know for
    absolute dead certain that phase perfect has these diagrams in house, because the *built* the things. Honestly it might be worth trying some social engineering
    (maybe lubricated with some hundred dollar bills) to obtain the diagrams from a PP employee. Or former employee....

    Otherwise it truly will a long slow effort to reverse engineer the boards. Some of the chips may be proprietary and some may have the numbers deliberately
    obscured. If I had infinite time, I'd start with doing a diagram for the thing. From scratch. This may involve actually unsoldering all the components so the
    board - probably mult level - could be fully traced out.

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    Quote Originally Posted by jim rozen View Post
    .... the board - probably mult level......
    Virtually any circuit board, if designed for loe EMI, is going to be at the minimum two sided (not hard to work with) but far more likely 4 level. The 4 level is still an inexpensive part, these days, but multiplies the problems of tracing out the circuit. Ones involving a DSP are far more likely to be 4 level at least because many DSPs and microprocessors have multiple power pins, and the connections tend to block all the other connections if you try to put them on just two copper levels.

    Worse yet, the faults that may occur include nasty ones like broken copper where an inisde layer connects to the "barrel" of a component lead hole or just a plain "feed through" connection.

    It's still not impossible, but...... One ends up having to ohm the connections of each component pin to all others, and developing a list from that. That is a lot of connections to check.....

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    Quote Originally Posted by jim rozen View Post
    Some of the chips may be proprietary and some may have the numbers deliberately
    obscured.

    Neither appear to be the case on the board I have so that is good news...….

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    "Proprietary" with DSP etc, is in the programming. The "chip" is more or less general purpose within the limits of its design.

    Now, you can in some cases, extract the code with proper equipment, assuming that it is not "locked". And that has been done. it does have the potential to be against Federal law concerning hacking and copying of computer software, although the probability of a prosecution is low, at least for repairs.

    In other cases, the chip has a "lock", which if set, will prevent, temporarily or permanently, anyone from reading the program contents. In many cases the "lock" does not prevent re-programming, but requires the existing program to be erased before a re-programming is done. Basically any access irequires erasing the program. Not helpful.

    To be fair, most of the special features and cleverness (if any) of the design is contained in the program, so one can hardly blame the makers for protecting their investment.. Lines of code in fully debugged and tested form are expensive, and the makers have every right to protect it, and will, if they have any sense. The laws against copying etc do not apply in other countries, particularly those most likely to shamelessly copy a product.

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    Quote Originally Posted by jim rozen View Post
    And this is the single largest impediment to getting one of these repaired. There is no available, comprehensive schematic for these. Troubleshooting electronics
    is nearly impossible with a schematic. One that hopefully includes pinouts, waveforms at various places. Now we're all adults in the room and we all know for
    absolute dead certain that phase perfect has these diagrams in house, because the *built* the things. Honestly it might be worth trying some social engineering
    (maybe lubricated with some hundred dollar bills) to obtain the diagrams from a PP employee. Or former employee....

    Otherwise it truly will a long slow effort to reverse engineer the boards. Some of the chips may be proprietary and some may have the numbers deliberately
    obscured. If I had infinite time, I'd start with doing a diagram for the thing. From scratch. This may involve actually unsoldering all the components so the
    board - probably mult level - could be fully traced out.
    There's another way. Don't "reverse" engineer it. Clean-sheet engineer it.

    Now.. one DOES start knowing what it must do..

    Also knowing what the already-paid-for lumped inductances (many!) and lumped capacitances, (several) and main pass-elements are.

    It isn't as if it was as complex as all that. "Relatively".

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    Quote Originally Posted by JST View Post
    Lines of code in fully debugged and tested form are expensive, and the makers have every right to protect it, and will, if they have any sense.
    This is the brave new world where, when you buy any item with code it in, you own the item but you don't own the code inside it. In my ideal world, when
    you purchase property you then own what lawyers call "the entire bundle of sticks." Not just a few of the sticks. All of them. This includes rights to
    decode and understand all the software inside.

    Probably when you buy a PP you have to sign those rights away in the form of a user agreement.

    Which is why I will never purchase one of those. (obligatory picture of phase converter with zero software content implied here)


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