Grounding (?) issue with Fisher X-100

Discussion in 'Fisher' started by beatcomber, Jul 13, 2017.

  1. gadget73

    gadget73 junk junkie Subscriber

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    Looks like an across the line cap, so that wouldn't have any bearing on voltage to chassis. If one end connected to the chassis, it would be a different story.

    Possibly the meter wasn't clicked all the way into the 200v spot? Dunno, looks like its on the right mode and such.

    I think I'd be tempted to verify leakage like Fred suggested. If its not excessive, put a grounded cord on it and call it a day. If it has a short from line to chassis, you'd have to figure out what is causing it otherwise it will blow the breakers.
     
  2. beatcomber

    beatcomber AK Member

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    I didn't flip the prong, I checked a different outlet in the same room.

    To recap:

    The power center is connected to an outlet that I updated from 2-prong to 3-prong; that one is giving me a 240v reading on the meter (but the power center says +-120v). I believe I correctly grounded the new outlet when I installed it (ran a wire from the plate to the metal case).

    I also meter-tested one of the original 2-prong outlets in the room (which is connect to a wall switch). That one is giving me a reading of 23v. Weird!
     
  3. bob06

    bob06 Addicted Member

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    If you had 240v from your outlet you would have fried everything by now. So I would say you have a faulty meter. Buy or borrow another one and try again. Also since you do not have a proper grounding wiring system in your house I would suggest talking to a electrician to see if there is away to properly ground your outlets without having to rewire the hole house. Running a wire from the outlet to your box I don't think is a good ground since the box itself is not grounded. But I could be wrong.
     
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  4. beatcomber

    beatcomber AK Member

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    According to the "ground" light on my power center, the outlet is grounded. (The light was not on when it was plugged into the old 2-prong outlet.)

    But I think I may have solved the problem! I made sure that the "hot" plug (the one with the extra bulge on the side of the wire) was plugged into the hot receptacle on the power center, and then made sure the other components (turntable, etc.) were likewise plugged in as well. I am not getting any tingling from any component right now.
     
  5. bob06

    bob06 Addicted Member

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    Sounds good to me.:D
     
  6. beatcomber

    beatcomber AK Member

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    Hmm, I spoke to soon. There is still a slight tingling... but I guess I will just deal with it.
     
  7. Patrice B

    Patrice B AK Subscriber Subscriber

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    Better to measure how much "tingling".
     
  8. bob06

    bob06 Addicted Member

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    Tingling is not good. Could be just a step away from electrocution. :yikes: I would not use it until it was fixed. :no:
     
  9. beatcomber

    beatcomber AK Member

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    Yeah, you're right. I'll bring it somewhere for servicing.
     
  10. gadget73

    gadget73 junk junkie Subscriber

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    Some old houses did actually have grounds with the 2 prong outlets. Mine does. There were 2 wires going to the outlet, and a third bare wire going to a screw inside the box. I verified the ground with the voltmeter and updated them to 3 prong. All of the outlets indicate a ground with one of those outlet testers, and with the voltmeter. Its not legal per code to install a 3 prong outlet in a non-grounded system.

    Would be worth confirming whats going on with that reading though. On the outlet itself, read each side to ground and across the flat pins. One should be 120v, the other basically 0v and of course 120v across the blades. If you're getting 240v anywhere, you've got serious wiring problems or the meter is lying.
     
  11. fred soop

    fred soop Super Member

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    As stated earlier, it appears that the "death" cap is not connected to the chassis. So, any leakage to chassis would have to be from another source, such as capacitive coupling in the transformer or a short in the transformer, or even a short inside the power switch. Maybe the switch cover has poked through the insulation. With the power switch on and the unit unplugged, you can check resistance from the blades of the plug to chassis. DC resistance will not measure the capacitive coupling, so should be very high. If there is a low reading (anything below 1 MegΩ), there is something leaking to ground in addition to transformer capacitance. That MUST be found and fixed to avoid a safety hazard.

    If the tingle is just capacitive leakage, it can be solved with a 3 wire grounded cord, but that may introduce problems with ground loops. The leakage can be minimized by reversing the plug for the lowest chassis to ground voltage. This is why the official standard leakage test described in post 11 is important. The RC combination simulates the human body connected between the chassis and earth ground. If you are unable to follow that, you should find someone that can perform the test.
     
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  12. beatcomber

    beatcomber AK Member

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    Thanks for the tips! I think it's time to bring my Fisher to a pro, which I will do.
     
  13. larryderouin

    larryderouin You can be sure if it's Westinghouse??????? Subscriber

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    You might also change the batteries in your meter and retest. That's one of the 1st things I would have done to Rule out or Rule in Meter faults.
     
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  14. beatcomber

    beatcomber AK Member

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    That's a good idea!
     
  15. beatcomber

    beatcomber AK Member

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    Thanks for everyone's input and assistance! It seems clear that whatever the issue is, it's beyond the my ability to diagnose and repair.

    I'll be dropping it off at a local hifi repair shop this evening. The technician on staff is an AK'er, so I trust it will be in good hands. I'll follow up once I get it back, which hopefully won't be too long.
     
  16. beatcomber

    beatcomber AK Member

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    The X-100 was dropped off last night... I'll follow up with the results.

    While I was at the shop (The Audio Lab in Harvard Square), the guy behind the counter (Mike) pointed out that he just put out for sale a super-clean, fully serviced 400 with the original wooden case. If I had had the bread to spend, I would have have bought it on the spot! It wasn't cheap but it wasn't overpriced either.
     
  17. beatcomber

    beatcomber AK Member

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    FOLLOW-UP

    I just spoke with the tech and he confirmed that the chassis is carrying 100+ volts, which is is excessive. His plan is to ground the power cable to the chassis.
     
  18. bob06

    bob06 Addicted Member

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    Simple enough. All my audio equipment that didn't have a 3prong plug does now. That was always the first thing I would do. Even my TT's.
     
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  19. gadget73

    gadget73 junk junkie Subscriber

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    I'd still want to know where that voltage is coming from. Grounding it might fix the symptom but if there is a leak somewhere you may find it shooting sparks from wherever the insulation failure is.
     
  20. bob06

    bob06 Addicted Member

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    That's a good question. Never thought of that. Hopefully beatcomber ask his tech that.
     

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