Kitchenaid KDS-58 (18?) electrical fault/schematic

[dnordenh]

Hi! New 2 Kitchenaid dishwashers, new to this web resource, high on both!

G/f got used KDS-58 recently that has responded favorably to my first aid and impressed us both. If I understand correctly this is essentially a KDS-18 converted to portable duty. Seems to run fine now that I've cleaned water inlet screen but we found out by accident that it has an electrical fault. When plugged into an outlet that really wasn't grounded after being stopped in dry cycle it would not advance to end of cycle and cancel/drain button made motor run endlessly but did not seem to advance timer. Dry light not lit, only flashes briefly once when practically any button is pushed. Also received a mild shock disconnecting water from faucet. That was one and only clue that outlet was not grounded.

All this leads me to believe that timer/lamps/control panel neutral return has somehow migrated to chassis/ground. As if the wire broke and is now making solid contact with chassis. Current flows from black wire to control panel and through my body to ground but is insufficient to light lamps and operate timer.

Could have tested theory running a ground jumper but was too puzzled and worried to trry it at the time.

As an electrical engineer I can conjure up no other explanation even if I know this is an unlikely failure mode.

Anybody know if this is a known problem and what to do? Anybody seen it before? Anybody got a schematic, manual or wiring diagram? Lacking any useful replies here I reckon I'll just figure out how to get at the wiring and visually inspect it.

Thanks!

Don

 

[soberleaf]

i'm sure i have a schematic for an 18

somewhere in all my stuff, i bought a realm of manuals from a guy earlier this year, tons of hobart stuff. i also just picked up an kdi-18 yesterday but it's not a superba and won't have the same timer or cancel drain.

one thing, when you hit cancel drain motor will run continuously till timer advances to it's off position.

i don't understand how a nuetral wire could cause a shock if it were touching ground. the nutral wire is not hot, it is the same as the ground wire anyway, at least once it gets back to the circuit breaker box. if you have a hot wire touching the frame or a current leak from a hot wire to the frame from any electrical component then yes, the frame will in essence be "hot" and if you touch any metal and touch a ground such as the water line, faucet etc, you'll get a shock.

i would run a circuit tester to the frame and check it.

it could be a current leak in any of the components. but since you are also having timer issues i am guessing it is not a leak in say a water solonoid, drain solonoid, the motor, or even calrod heating elements or dryer. but i could be wrong. if i could not find an obvious explanation i think i would start testing each component seperately off the machine for a current leak.

i'll see if i can find a schematic for you.

 

[everythingold]

Damn, welcome. The KDS-58 is no match for you, with a little help from Automaticwasher.org matt

 

[everythingold]

Electricity...

I've experienced "live" appliances on a number of occasions. Some made my voltage detector sing over the entire body. This is what I understand to be "potential voltage." It is caused by a power wire gaining exposure to the body. Or by gaining exposure to the neutral wire. I'm a novice here, but from what I've been taught, a neutral is something grounded to itself. So a neutral can potenitally charge the body of an appliance. If a connection is made, a mild shock will occur, if it is properly grounded. A ground being an open conduit to a larger system that can "absorb" the current. If the appliance is not ground, a full throttle shock can occur. The scariest electrical expience I've had was checking the element on a Tappan Fabulous 400. It was on a wall bracket, so unplugging it would have been a chore. And I was too lazy or preoccupied to shut off the breaker. I turned on the oven switch and put my voltage detector to the back of the bake element. It pushed the element enough so that the portion that goes through the back of the oven made contact with the frame. The result I can only describe as an "explosion" that blew a quarter sized hole where contact was made before popping the breaker. Luckily, I was not touching the machine, but my plastic voltage meter was toasted. I have had other less dramatic but weird experiences. Mice like to chew wires (rats can chew through a copper refrigerator line, got pics to prove it.) Now, I always unplug the machine. LOL, TYG. matt

 

[cornutt]

Shock from neutral

"i don't understand how a nuetral wire could cause a shock if it were touching ground"...

It could do it if the outlet is wired with reverse polarity. Check the outlet. It could also do it if the house neutral is floating, but usually that causes lots of other problems around the house.

 

[soberleaf]

maybe this will help

there are two sides to house wiring, a hot side and a nuetral ground side. a hot wire has the potential of 120 volts if it can find a way to back to nuetral ground earth. if the hot wire is connected to a nuetral wire then the circuit is complete. currect flows. if the hot wire is connected to the ground wire (green wire) then the circuit is complete, currect flows. if the hot wire is connected to anything that connects to nuetral earth ground then the same thing. that's why if you touch a hot wire and touch a water pipe you get 120 volt zap. if you touch a hot wire and are standing on uninsulated ground you get a zap. if you touch a hot wire and are on a wooden ladder you don't get zapped. cause the wood insulates you from ground earth.

the power lines that comes to your house comes in with 2 hot wires and a nuetral ground. connect one hot wire to nuetral ground and you get 120 volts. if both hot wires are connected you get 240 volts. that's house wiring.


after the service entrance cable comes in your house from the street it goes to your circuit breaker box or fuse box. both hot wires connect to seperate metal bars that will connect them into breakers or fuses. the nuetral connects to a nuetral ground bar in the box. all white nuetral wires from the from various lines that feed your receptacles throughout your home connect to this nuetral bar. all hot wires (black) connect to the circuit breakers or fuses. that way when you plug something in currect flows thru the breaker or fuse, thru the appliance back to nuetral ground earth and the circuit is complete.

any line that has a 3rd ground wire (green) will have this green ground wire connected to that same nuetral ground bar in the box. this 3rd. wire is simply a 2nd nuetral ground wire, just like the white wire. the difference is the white wire connects to electrical circuit of the appliance. the green wire connects to the appliance frame. basically grounding the frame of the appliance to nuetral earth ground so that if there is a short somewhere and you touch the appliance you won't get zapped as the currect won't have to flow thru you to reach ground. the frame is already at ground.

so if you connect anything to a hot breaker and that nuetral bar you get 120 volts out of that box. if you connect anything to 2 hot breakers from both hot lines in the circuit breaker box you get 240 volts.

if you touch a hot line and you also touch a nuetral line you get a zap of 120 volts. if you touch a hot line and touch anything else connected to "ground" you get the same shock.

current must "flow" from the hot side to ground to shock you, or run an appliance. you can touch a hot wire and as long as your body does not come in contact with nuetral ground you won't feel anything. the current cant flow back to ground. if you touch a hot wire and grab a faucet then the currect can flow thru you into the faucet and thru the water pipe completing it's way back to ground. you get zapped.

all 120 volts appliances have 2 wires as we know. one is the hot side, one is the nuetral/ground side. bigger appliances have a 3 wire cord and plug. this 3rd wire is also a nuetral wire meaning it is not "hot". it is a seperate path to ground from the appliance. the ground wire connects to all metal parts of the appliance (frame, motor etc) and when that ground wire is traced back thru your housde wiring to the circuit breaker box or fuse box it connects directly to that same nuetral bar that all other nuetral wires coonnect to.

so by adding a ground wire to an appliance it in effect grounds that appliance to "nuetral/ground". so if there is a short somewhere, say in a timer, that short will be directly carried back to ground by that ground wire. even if you touch the appliance and touch ground (water pipe etc) you won't get shocked as the currect has a better path to flow thru rather than your body.

if however an appliance is not grounded properly or that grounding wire is not connected properly to ground nuertal in your circuit breaker box then if there is a short the entire metal appliance will have the potential to shock you if you touch it and provide any way for that currect to flow thru you back to nuetral ground. you could be touching a water or gas pipe, or standing on ground itself.

so remember, electric wire is either "hot" or not. if it's a hot wire and you provide anyway for currect to flow to nuetral ground then it will. if it's a nuetral ground wire it has not potetial at all. and again the 3rd wire, the green ground wire ground is nothing more than a nuetral wire, ground wires and nuetral wires are all connected together in the circuit breaker box. they have earth ground potenital and are connected to earth eventually.

and matt (everythingold) yes you are right to a certain point. a potential voltage is something connected to a hot wire. if you touch it and can complete the circuit to earth ground via your body you get zapped. but nuetral wires have absolutely no voltage potential at all. neither do ground wires. they are at earth ground and can not zap you.

this is long winded i know but so many people get confused on this and it's really simple. currect must flow to do anything. it must flow from it's "potential" hot side back to earth ground to work. that's why there are always 2 wires, hot and not! when hot and not connect then the currect flows at 120 volt potential (in house wiring). if something has short in it and you touch it and touch earth ground you are competing the circuit and it flows thru you, hence a zap!

 

[dnordenh]

Thanks for the replies!

Folks, I am pleased at the number of replies and thank you all. I don't see the answer I was looking for. I was hoping somebody would say "Oh. When the lights and timer motor work only when the machine is plugged into a properly grounded outlet and you get a mild shock when plugged into an ungrounded outlet you need a new thingamajig or check the blue wire with the white stripe between X and Y. So this is not a known problem or common failure mode. No surprise I get a lot of the stinkers.

But to all who wrote with questions or lessons on household wiring, let me try to clarify. Let's say that one side of all the lamps and one side of the winding on the timer motor are supposed to go to a terminal/junction somewhere inside the control panel. Let's call this the neutral terminal for the control panel. One side of the various dispensers may connect to this terminal too. I can only guess since I don't have a schematic. Nor do I know if any of those things function or not when plugged into an ungrounded outlet.

Now let's say another wire goes from that neutral terminal/junction near the top of the door to the electrical box where the power cord enters the machine. Inside that box this neutral wire is somehow connected to the one from the cord and the ones going to the various motors and heating elements, etc.

Now let's say from 25 years of use the neutral wire between the control panel and the main junction box has been damaged. Maybe the 'faston' connector in the main junction box has popped off and is touching the green screw where the green wire of the power cord is screwed to the side of the junction box thus grounding the machine safely. The lamps and timer motor have no return neutral path now. It's broken. When the machine is plugged into a grounded outlet, however, the return is now through the green ground wire, not the white neutral. Everything seems to work. The owner is not aware and nobody gets a shock.

Now suppose the machine is plugged into an ungrounded outlet. The lights don't light and the timer doesn't go because their intended neutral return is busted and the accidental ground path return that let it run when plugged into a grounded outlet is no longer there. But when the unsuspecting owner goes to disconnect the water he gets a mild shock. Current comes into the machine on the black wire, gets to the light and timer through the door switch and some timer contacts, etc. goes through the lamp and timer motor, gets half way to the power cord, contacts the chassis or green wire instead of the neutral, flows through the water-filled hose through the owners right hand, through his arms, torso and left hand to the faucet and ultimately to terra firma.

It is some variation of this theme that I suspect. The water in the hose conducts electricity well enough to give the owner a mild shock. The resistance is too high to give the light and timer the current they need to operate.

If it were only the timer motor and not the light that were not working I would suspect a problem in the motor winding itself. But it's both so I suspect something common to both that is only evident when the green wire path to ground is missing. Maybe the wire itself has broken from one flex too many. Maybe a million things. I have nothing to stop me from tearing everything apart and visually inspecting it all and making resistance/continuity measurements. I was just hoping somebody would have seen it before or been able to offer a wiring diagram.

Thanks to all. If/when I fix this I will tell the story here. That may take a few weeks. G/f can wash dishes by hand for a while or eat off paper plates. Besides, she eats out or at my place much more than she eats at home anyway. Thanks again and all the best!

Don

 

[everythingold]

Someone has to have the schematic. Thanks for all the info on electricity, it is useful. Unfortunately, most of the problems a repairman runs into are from a house with 3 layers of wiring rigged in by a do-it-yourselfer. I have run into some strange problems, like an outlet (spurred off a 220 line) that would run an older hotpoint dryer, but not a newer KA. Of course it tested fine, but the wiring in the house was just a mess. But at the end of the day, I am an appliance guy, your household electric is not my problem. matt

 

[stevet]

It is under your nose!

Well, not exactly....

The wiring diagram is actually pasted to the inner door of the machine. Take off the outer panel(4 screws hold it in place) and it will be staring you in the face.

Two things to look for.. miswired outlet as previously mentioned and a broken wire underneath the unit.

Caution:!!!!!
Even under a correctly wired scenario, there are still live terminals under the machine. If you miswire the outlet, things like the bimetals in the detergent dispenser are now live and can overheat and cause the dispenser to burn up! My cousin's KDI-18 had that happen when the installer used an appliance cord to connect it to the wiring on the machine.He connected the hot wire of the cord to the white wire on the machine and black wire to the neutral on the house side. He lost the dispenser and the bottom rack, and almost burnt his new kitchen down!

Hobart loved to make multiple connection with the white neutrals all over the bottom of the machine; so unplug it and turn it over or on its side and check for broken or shorted connections. I bet you find it!

I had that happen to my KDS18 just like you have going on and I stupidly forgot to check the wiring, condemned the timer and destroyed the timer by taking it apart and then not being able to put it back together. I now have 2 spare brand new timers for that machine!

Anyway,look at the wiring diagram and check the wiring connection points. Also, check the thermostats attached to the probe that comes thru the sump. They carry 1400 watts of current at times and could have melted. Another common occurence in older machines that have been used. Also check the overload protector on the blower housing. They crapped out too and could cause the short too.

Let us know what you find

 

[dnordenh]

Mystery solved

Okay. I figured it out. I have to thank stevet for telling me the wiring diagram/schematic was inside the front panel. That helped a lot.

To recap: The dishwasher worked nicely when plugged into a grounded outlet. Plugged into an ungrounded outlet the timer would not advance and the lights would not light. I got a shock when I tried to disconnect the water hose. I suspected some kind of ground/neutral fault that caused the neutral return from the lamps and timer to take the green wire instead of the white one.

Well here's what I found. The white wire going to the controls was disconnected from the water inlet valve. That's probably my fault from when I took the valve out to clean the screen. But I also found that one of the timer motors has an internal short from winding to case. I've attempted to take it apart. It's not gonna work. I need a new timer motor. I haven't found one on the web. Anybody got one or know a drop-in substitute?

I do not know which timer motor it is. It has one lead about 2" long and another about 6", both black. It is marked as follows:

Singer Controls Co of America model 414-268-20 115V, 60Hz, 3W, 2-2/3 RPM CCW. The motors I see on the web either don't specify speed or direction or they're way above or below this speed.

Knowing what I do about manufacturing, I think it likely that other manufacturers used similar motors. If this is the fast/cancel timer I guess the speed is not critical. Anybody knwo which one this is? I took it with my from my g/f's and I didn't try to figure it out when I was there...

Thanks!

Don