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Need help installing to a 500-C on-off switch a CL-60 current limiter

Discussion in 'Fisher' started by thornev, Feb 11, 2018.

  1. thornev

    thornev Active Member

    Messages:
    479
    Location:
    Mid Hudson Valley, NY
    I just spent the last 4 hours hunting for information on how to install this CL-60 in my 500-C. I've got a rebuilt power supply board where the AC lines enter the chassis so I can't do anything there. I believe I have to install it near the on-off switch. I know it gets hot so will do the best I can to isolate it from other components.

    My problem is that there are 3 brown wires coming out of a metal conduit and these 3 wires are attached to all 4 lugs on the on-off switch. I don't know which wire I can clip and then insert the CL-60. I've included a picture.

    Thanks, Thorne
     

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  2. larryderouin

    larryderouin Turn it UP, POP? PLLUUEEEZZZZZEE Subscriber

    Messages:
    21,791
    Location:
    Glen Burnie Md.
    The leads out of the shield are different colors (they are probably faded) BUT! one comes off the power cord to the switch. The other two go to 1.) the Aux power plugs, and 2 back to the transformer. Follow the shield back to the area where the cord comes in. Trace the 3 wires to their termination. The one that terminates on a terminal strip with one side of the power cord, is where the the CL gets installed. DeSolder the power cord from the strip, and solder the CL-80 between the power cord and the switch lead. And that's it.

    A CL-60 is rated for 10ohms resistance and 5Amps. Too little for resistance and too much for amps. A CL-80 is actually the ideal thermistor for 1.) cold resistance to ramp up to line voltage. 2.) Amperage for total load. The CL-80 is rated 47ohms and 3a.

    A 500c is rated for approx 180W (1.8A) under operating conditions. With a CL-80 3A will be plenty enough for initial turn on surge. 47 ohms will give you a 2-3 second ramp up while a CL-60 gives you pretty much no ramp up, and with a 5A rating it will not be loaded down enough to actually work as intended. You want the amperage to about equal the Main Fuse Rating which on the 500c is a 3.2A slow blo. So 3A is practically ideal with regard to the amperage rating, and the 47ohm is enough resistance to minimize or alleviate further arcing on the switch contacts. A CL-60 WILL NOT DO THIS.

    Take a picture (close up) of the back of the chassis where the power cord comes thru the back of the chassis and where the power cord connects to.
     
  3. thornev

    thornev Active Member

    Messages:
    479
    Location:
    Mid Hudson Valley, NY
    Boy, Larry, you and Dave have been so kind, thanks so much for your help.

    I've attached a picture of where the AC comes into the chassis. Thanks for your response, but I'm afraid access to where the power cord "terminates on a terminal strip" is too challenging. And that's because the terminal is under the SDS Labs add-on board that a previous owner installed. (thanks for letting me know CL-60 is insufficient).

    Thorne

    PS - I tried to remove the SDS Labs board and it won't budge. It is well-attached. I would have to unsolder and cut a whole lot of wires. I can't even slide it over a little to expose the terminal. Sigh. There's has to be a way I can use a DMM to figure out at which wire attached to the on-off switch I can insert the CL80. (he said with great hope) I mean one of those wires must carry the house voltage to the on-off switch which would be where I could attach the CL-80, no? That's where there is the most room for it.

    The 3 wires attached to the on-off switch are different colors. They are orangey, light brown and dark brown. Maybe that's a clue? In metalbone's resto kit there is a picture of those 3 wires where they are attached to the terminal of which you spoke. And in that picture he has the CL-60 attached to one of the house AC wires (which also is attached to one of the other AC plug terminals on the back of the unit which is also attached to the orangey wire) and the other side attached to the dark brown wire. What do you think? I've attached 2 pictures. One of why I can't get to the terminal of which you spoke and the other is of how metalbone has the CL-60 attached which shows the 3 wires that attach to the on-off switch.

    I've attached a picture (well, my non-electronic art work) of what I think is the way all the AC wires are hooked up to the on-off switch. If I'm correct I would think I could unsolder the dark brown wire from the on-off switch and connect one end of the CL-80 to the unsoldered wire and the other end of the CL-80 to the terminal to which the unsoldered wire was previously attached, right?
     

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    Last edited: Feb 11, 2018
  4. larryderouin

    larryderouin Turn it UP, POP? PLLUUEEEZZZZZEE Subscriber

    Messages:
    21,791
    Location:
    Glen Burnie Md.
    Put your meter on ohms. Connect with mini grabbers the Dark Brown wire at the switch, and also one of the prongs on the plug. You'll either get an OPEN or a 0.0 or slightly higher ohms reading. The 0.0 reading is the lead to the switch. Disconnect the dark brn wire at the switch and install the cl-80 between the Dark Brn lead and the switch. Situate the cl-80 away from everything else in the area.
     
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  5. thornev

    thornev Active Member

    Messages:
    479
    Location:
    Mid Hudson Valley, NY
    Thanks, Larry. I assume that test is the same as a continuity test. I get continuity at the switch, dark brown wire, and one of the 2 plug leads. I also get continuity at the switch at the light brown wire and the other plug lead. Based on my drawing of metalbone's CL-60, I would think I want the CL-80 at the dark brown wire.

    Oh...and of course it would have to be the hardest wire on the switch to get to !
     
    Last edited: Feb 11, 2018
  6. larryderouin

    larryderouin Turn it UP, POP? PLLUUEEEZZZZZEE Subscriber

    Messages:
    21,791
    Location:
    Glen Burnie Md.
    Yes you are checking for continuity.

    If the Dark Brn wire is by itself on one side of the switch, then yes. On one side of the switch will be a single wire, and 2 wires on the other. The single wire is the cord line.

    The other wire(light Brn) having continuity to the plug's other side worry's me. Take that reading again and let me know what it is! It should be a very high reading if anything. Not too many have been involved with a 500c SDS board and it's permutations, and I'm not one of them. So I'm not sure how the whole thing shakes out. I'm not sure if Dave has experience with it but he might.
     
    Last edited: Feb 11, 2018

     

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  7. thornev

    thornev Active Member

    Messages:
    479
    Location:
    Mid Hudson Valley, NY
    The light brown wire connects to the middle terminal of the terminal strip to which you referred (see the middle picture in post# 3).

    Touching electric lead A and:
    orange wire at on/off switch = 2.2 ohms (continuity)
    light brown wire at on/off switch = 2.2 ohms (continuity)
    dark brown wire at on/off switch = "OL" (out of range)

    Touching electric lead B and :
    dark brown wire at on/off switch = .5 ohms (continuity)
    orange wire or light brown wire at on/off switch = "OL"

    Now, I was able to determine that electric lead B goes to the terminal strip, and electric lead A goes to the empty electric plug on the outside of the back of the chassis. What bothers me is that electric lead A connects to both the top and bottom inputs of the plug on the back of the chassis (i.e. I get continuity touching both terminals). I wouldn't expect them both to be connected as I would think that would cause a short, but maybe that's the way AC works since it cycles back and forth?

    Thorne
     
    Last edited: Feb 11, 2018
  8. thornev

    thornev Active Member

    Messages:
    479
    Location:
    Mid Hudson Valley, NY
    Larry - I've attached the wiring diagram that is used to figure out where to insert the CL-60/80. Thorne
     

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    Last edited: Feb 11, 2018
  9. larryderouin

    larryderouin Turn it UP, POP? PLLUUEEEZZZZZEE Subscriber

    Messages:
    21,791
    Location:
    Glen Burnie Md.
    You lost me with the Electric lead "A" and "B". Are these the power cord wires?? If so A is miswired as there should NOT be continuity on both sides of the aux power plug to that lead. There should be a lead fromthe back side of the fuse to one side of the AUX plugs and the Lead "A" to the other side. If you get continuity btwn the upper and lower plug side, then either someone jumpered it, or the plugs are shorted. Like i said earlier, I'm not familiar with the SDS board and how it's hooked up. It might be a viable solution to replacing the can caps but they contribute greatly to the heat load underneath, and with the caps on the underside the heat is trapped around them. It's similar in operation to the larger PIONEER SX-727-828-838-939 and 1010 power supply boards that were mounted underneath and upside down and the P.S. literally cooked themselves to death. Me personally?? I'd convert it back to original and run it as designed by FISHER. Then you have room to work, very little is getting roasted. And it follows the schematic.

    Have you checked the switch to see if it is actually switching off and on??? Use the meter on the contacts of the switch. One probe on the Dark Brn and the other probe on the wht or orange. one test switch OFF and one test switch ON. Leave the cord unplugged!!!!!!!!!! We want to make sure the switch is actually working correctly.

    If it is, wire in the CL-80 btwn the Dark Brown wire and the switch.
     
  10. thornev

    thornev Active Member

    Messages:
    479
    Location:
    Mid Hudson Valley, NY
    Yes, I was saying that A and B are the 2 sides of the unit's electric plug. And you're right... The 2 sides of each of the two AUX power plugs are wired together (i.e. there is continuity between them) that is assuming my DMM isn't whacked out. I'll do some more investigation because something isn't making sense. I put an ohm meter on the 2 sides of the AUX plug and it settles around 1.4 ohms.

    By the way, metalbone says the colors are supposed to be white (what I've been calling light brown), orange and brown (what I've been calling dark brown). He confirmed that the CL-80 should be inserted between the brown wire and the switch lug to which the brown wire was attached.

    The on/off switch on the receiver works fine. It does what it's supposed to. BUT... I get unexpected continuity results with the switch in the ON and OFF positions and testing with a DMM on all combinations of switch lugs (with the unit unplugged of course!). To summarize (Y = continuity exists):

    switch : ............ ON.........OFF
    brown..................Y..............N.............white
    white...................Y...............Y.............orange
    orange.................Y..............N.............brown

    Keep in mind that of the 4 lugs on the switch, 2 of the lugs are connected with a bare wire which is attached to the brown wire. So where it says "brown" in the above table, that counts for 2 of the lugs on the switch. I don't know how the switch is wired internally.

    Thorne

    PS - It occurs to me that it's possible there is already a current limiter installed under the SDS Labs board. Is there a way I can test how the current works at the on/off switch when the unit is turned on? Can I use a multimeter to monitor the current? If a limiter is installed I guess I would see the current rate climb more slowly than if one isn't installed? Of course I don't know what a normal current rate is so I don't know that such a test will present useful results.
     
    Last edited: Feb 12, 2018
  11. Catmanboo

    Catmanboo AK Subscriber Subscriber

    Messages:
    483
    Location:
    Atwater, ohio
    Thorne,Do you have the 500c schematic? This may help. You're lucky in that your switch has had the shroud removed, or maybe never had one. Helps to see the goings -on. Notes from my schematic, thermistor can go in at the 'x' marks. Brown shield wire goes from line cord to switch toggles (jumped at switch) via terminal strip.
    Orange wire goes between one switch leg & accessories outlets. White wire goes from other switch leg to primary (one of the twisted black wires that go through the chassis ) of power transformer. Thermistor goes between either power cord leg & everything else. Pm me if you want.
     

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  12. thornev

    thornev Active Member

    Messages:
    479
    Location:
    Mid Hudson Valley, NY
    Catman - Thanks for the response. I do have the schematic. I cannot install at that point because it's covered by a large add-on board that I cannot remove without a lot of wire cutting and unsoldering. I have to install at the on/off switch where there's plenty of room. Thorne
     
  13. Catmanboo

    Catmanboo AK Subscriber Subscriber

    Messages:
    483
    Location:
    Atwater, ohio
    Ok, I should've looked at all your pics. Put it between the brown wire & where it attaches to switch. You'll take brown wire off switch , put one leg of thermistor on this lug. Put brown wire that you pulled from switch on the other thermistor leg. Ideally, it would go between the other leg of power cord & the acc.outlets/fuse holder, but it's too crowded in there now for a heat-generating device.
    You'd be s.o.l. if your pot/switch assembly looked like this, which is how it once did!
    Make sure that nothing touches anything else, especially the shield. Don't want sparks!
     

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  14. thornev

    thornev Active Member

    Messages:
    479
    Location:
    Mid Hudson Valley, NY
    Yep. I will put shielding around the thermistor's wires and bend it so it's as far away from all other components. Thorne
     
  15. Catmanboo

    Catmanboo AK Subscriber Subscriber

    Messages:
    483
    Location:
    Atwater, ohio
    :thumbsup: some call that a flying connection, you've not much choice, unless you put a terminal strip in there to mount it on. That would be more hassle than its worth for you.
     

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  16. thornev

    thornev Active Member

    Messages:
    479
    Location:
    Mid Hudson Valley, NY
    Finally finished the job. Picture attached.
     

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  17. Catmanboo

    Catmanboo AK Subscriber Subscriber

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    :thumbsup: perfecto!
     
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  18. larryderouin

    larryderouin Turn it UP, POP? PLLUUEEEZZZZZEE Subscriber

    Messages:
    21,791
    Location:
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    Looks good.
     
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  19. Catmanboo

    Catmanboo AK Subscriber Subscriber

    Messages:
    483
    Location:
    Atwater, ohio
    Ya know, thorne, I may put the thermistor in my 500c with the missing switch in the same place on a terminal strip in that same loc., so that if I ever find a replacement switch, it's a 15 minute job to rearrange everything. That's likely the most benign place in these things for a hot part like that.
     
  20. thornev

    thornev Active Member

    Messages:
    479
    Location:
    Mid Hudson Valley, NY
    Catman - I had never used Bitcoin before and it was a real pain, but if you want, I can guide you through the process so you can get a switch from metalbone. Actually, I went through the process and later realized I didn't need the switch. I needed only the thermistor because my switch worked fine. I want to keep the switch just in case something happens down the line. Wha'd'ya say?

    The other thing that stinks about Bitcoin is that between the time you purchase bitcoins, when your transaction clears, and when you're allowed to send money to someone, the value of Bitcoin can go down so your money isn't worth what it was. You'll have to ask Metalbone how he would deal with that scenario. I remember that it took about 8 days for my purchase of Bitcoin to clear. The purchase was done through Coinbase. There are a few different Bitcoin merchants. It's a real scam if you ask me.

    Thorne
     
    Last edited: Feb 13, 2018

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