20 yr old VFD troubleshooting

Discussion in 'General Electronics Chat' started by electronis whiz, Feb 25, 2015.

  1. electronis whiz

    Thread Starter Well-Known Member

    Jul 29, 2010
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    I was given an old magnetek 503 VFD by a friend that's an electrician. He teaches the electrical classes at a college, he didn't seem to recall anything besides its and old VFD they got somehow and they have no need for it. He seemed to think it was possibly part of a donation from someone.

    Anyway here's my question. I could kind of tell looking at it it was kind of old, the rear heatsink was caked with some sort of black crud, the fan bearing seemed to be failing. It has some sort of inspection mark on it dated mid 1995 (not sure that was the place that made it or installation, etc). It's made for 3 phase 480V he said he saw no reason 120 single wouldn't run it. I also tried using a variac and transformer to boost 110 to 480 single phase. I'm still having the same issue with it though.

    When I power it up I hear the electronic inrush type sound, about 8-10 sec later the control panel/LCD come on.
    LCD says CPF00 which according to the manual has many meanings.
    Fault: Transmission error or control function hardware fault (including internal RAM, external RAM or PROM.)
    Description: Transmission between the GPD 503 and remote operator is not established within 5 seconds after the power supply is turned on. (Displayed on remote operator.)

    It's displaying error so display seems to work, I see no blown caps, fuse, etc inside of it. I see one fairly large IC dated 1986. It also has a pair of removable ICs like the really old PC bios used. I reseated these chips to no success. I'm thinking because it's so old maybe something is corrupt. It shows the error so i'm thinking at least some RAM and the firmware must be intact. It takes about twice as long for it to come up so i'm wondering if maybe even at 480v single phase it's not charging the caps, and PSU fast enough.

    I know I could ask my friend if in one of the labs they have if they have access to or some way to create 3 phase to test it and see if my last guess was correct.

    Want to see what people think if it's related to input power or a failure of something in the drive. I'm really tempted to just part it out because even if works on 3 phase 480 I don't think i'd have any use for that.
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
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    It is quite possible it has problems if it was a donation, and as a rule 480v VFD's are not recommended to run on 1ph , particularly on 240v.
    If you can get it tested on 480 3ph may be the best.
    Max.
     
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  3. electronis whiz

    Thread Starter Well-Known Member

    Jul 29, 2010
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    I thought of that as well. I don't have the stuff at home to run it. I got a working smaller AB 1336 II sensorless vector too. That was one they had used and will do 110/220. If the 480 one won't and condition is very questionable probably best part it out. Unless can run on 110 and make it into a signal generator or something, but that logic seems it's toast on the 480V unit.
    I also have to question what it was used for, the knockouts are intact, but front cover has notches out of side of front cover someone had just chopped out with dikes, etc. Maybe was some ancient trainer then but students never seem to treat stuff that well so very possible got a ESD zap, banged around, etc.

    Nothing else got a case, big caps, giant transistors, etc. Probably could use in some PWM setup for smaller stuff or like solid state relays.

    I think when I see him i'll see he has any way to do real test on it and connect it as intended or similar if have to use a conversion transformer of some sort.
     
  4. MaxHeadRoom

    Expert

    Jul 18, 2013
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    They usually have a nice large bank of electrolytics and a 3ph bridge, which you can use in 1ph.
    Max.
     
  5. alfacliff

    Well-Known Member

    Dec 13, 2013
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    these driuves were made by yaskawa, and have a common failure. the main board ( the one with most of the chips on it) has a small electrolytic around the center of the top of the board. it goes bad, messing up the 5 volt supply. I dont have one open right now to tell you the value of the cap, sorry.
     
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  6. electronis whiz

    Thread Starter Well-Known Member

    Jul 29, 2010
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    HMM i'll look into that. I saw nothing obvious from bulges, but sometimes the bases of the caps fail instead.
     
  7. alfacliff

    Well-Known Member

    Dec 13, 2013
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    they tend to leak out the bottom. heat the leads and smell for the charistic "cat pee" smell.
     
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  8. electronis whiz

    Thread Starter Well-Known Member

    Jul 29, 2010
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    I'll give that a try. I took the board out of the unit to look over. I see a pair of caps there both look relatively normal. One was a bit tilted sideways I pushed it a little and it straightened out and lead slid inside it. That cap is near the place you said close to the edge. 47UF 35V, another offset and in further is 220UF 6.3V. All of the caps on this board are nichicon brand.

    There are 4 others right against the inside of the connector for the ribbon wire that goes to the PSU/driver PCB.

    Here are some pics. I'm looking at the ones to the side of the ribbon connection. The one closest to that edge of the board was the one that was bent a little. Usually that's not a huge deal, and i've never seen one go like that, but could be worth trying to swap.

    Pics of the PCB:
    Entire main board
    drive PCB.jpg
    Faulty caps ? #1
    mid-cap-1.jpg


    Faulty caps? #2 mid-cap-2.jpg

    These are the other caps by the connection. The ones it seems are known to fail are towards the side
    IMG_20150226_104406.jpg

    Here are a few pics of the bottom of the PCB.
    This shows the bottom ribbon connection and the cap leads next to it.
    IMG_20150226_112014.jpg
    This shows the entire bottom of the PCB.
    IMG_20150226_112053.jpg
     
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  9. alfacliff

    Well-Known Member

    Dec 13, 2013
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    the holes the cap leads go thru are very small, and will cause you a bit of trouble rewmoving them, so be careful.
     
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  10. electronis whiz

    Thread Starter Well-Known Member

    Jul 29, 2010
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    ^ will do. Don't help the leads are bent over and bulk of board has hot snot or something over it. Sure the hot snot will smell good when heat that up LOL.
     
  11. alfacliff

    Well-Known Member

    Dec 13, 2013
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    I have fixed several of those supplies, and its ususally the same thing, only a few times was it the rectafier or output. it is under several brands, a/b, p&h, magnetek, and others. some use red cases, some white, and some yellow. sorry, I never got any schematics or service info on them (as usual).
     
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  12. electronis whiz

    Thread Starter Well-Known Member

    Jul 29, 2010
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    I may have found the issue. I decided take a look at the drive/PSU board also. I noticed an odd diode. Over on left side by the charge LED and a couple mosfets there's a big ceramic looking diode. Has a couple bands on it parts of the bands are missing like maybe got too hot and burned off. Then noticed 2 larger 75K ohm resistors that look to be in series. There both measuring about 68K which seems kind of out of the 5% tolerance the claim.

    My experience a resistor fails something else likely has also due to value change, or somethings is stressing the resistor and making it fail.

    I tested some diodes also using diode test on my DIMM register only one way, others have like a 450 value then reverse is like 800.
     
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  13. BR-549

    Well-Known Member

    Sep 22, 2013
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    A VFD not only controls the speed, it protects the motor.

    If the drive does not see 3 phases at the proper levels and phase.....it will shut down.

    I would not assume the drive to be defective until I gave it a proper load and the proper supply voltage.

    It's been quite a while, but I have repaired many drives.

    I never came across a 480 drive that would run on a single phase, let alone a lower supply voltage.

    Some of those old drives are surprisingly reliable and rugged.
     
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  14. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Most meters in the Diode test position shows the volt drop in the fwd direction, .5v .7v etc, should register open in the reverse.
    There is insufficient current in the resistance scale position.
    Max.
     
  15. electronis whiz

    Thread Starter Well-Known Member

    Jul 29, 2010
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    Just had kind of a funny thought. the main board in this drive is close to motherboard size. An Arduino could probably do a lot of the same stuff in a few inch space.
     
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  16. Vatorboy

    New Member

    May 1, 2015
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    Hi Alfacliff,

    I found this thread through Google and I'm having the same error code(CPF00) on an old Saftronics drive for an elevator. The only difference is that I have two elevators so I was able to swap out the upper power board to the elevator with the error code and the error is cleared, so I'm sure it is the power board and not the control card. You mentioned that sometimes the problem is with the power board. Could you direct me to where to look to find the possible problem on the power card? I attached a picture of the board. Thanks so much for your help!

    image.jpg
     
  17. Vatorboy

    New Member

    May 1, 2015
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    Hey ElectronicsWhiz,
    I saw your problem and posted a problem of my own. Is there a suggestion you could offer as well? Thanks!
     
  18. electronis whiz

    Thread Starter Well-Known Member

    Jul 29, 2010
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    I ended up kind of just giving up on it. It would have been cool to get working, but even if I did it was made for 480V which is nearly useless to me. And it's so dinged up, dirty it's not really ebay worthy. I saw it had some big caps, relays, etc I decided to part it out and put it all in a box maybe do something with the transistor devices mounted on the case.

    I have a smaller 110/220 AB unit that I know worked fine when I got. For what I want that unit will work fine.

    My only real theory as to the problem drive is something failed that I can't detect or maybe it's got some corrupt firmware. If I recall right my unit control board had an UVprom on it, it also sat on desks, etc for years with the cover loose or off it so who knows maybe it even got an ESD zap.
     
  19. ian field

    Distinguished Member

    Oct 27, 2012
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    The times I've found those while going over the soldering as something to do while I think about the problem.............

    Very often the escaping electrolyte eats through one of the capacitor's legs, these also show up as no longer attached to anything while re-working the solder joints.
     
  20. Vatorboy

    New Member

    May 1, 2015
    5
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    Well, I'm happy you got something that worked for you! Thanks for your help, buddy! I may have to give up too and just order a new drive but I was hoping to fix the board that I know has a problem somewhere on it. Thanks again!
     
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