[Mirrors]

Notes on the Troubleshooting and Repair of Small Household Appliances and Power Tools

Contents:


  7.85) Curling irons


These are just a sealed heating element, switch, and thermal protector
(probably).  Check for bad connections or a bad cord or plug if there is
not heat.  A failed thermal protector may mean other problems.  While
these are heating appliances, the power is small so failures due to
high current usually do not occur.


  7.86) VCR cassette rewinders


Cassette rewinders typically consist of a low voltage motor powered from
a built in transformer or wall adapter, a belt, a couple of reels, and some
means of stopping the motor and popping the lid when the tape is fully
rewound.

Note that some designs are very hard on cassettes - yanking at the tape
since only increased tension is used to detect when the tape is at the end.
These may eventually stretch the tape or rip it from the reel.  I don't
really care much for the use of tape rewinders as normal use of rewind and
fast forward is not a major cause of VCR problems.  Sluggish or aborted
REW and FF may simply indicate an impending failure of the idler tire or
idler clutch which should be addressed before the VCR gets really hungry
and eats your most valuable and irreplaceable tape.

Problems with tape rewinders are usually related to a broken or stretched
belt or other broken parts.  These units are built about as cheaply as
possible so failures should not be at all surprising.  The drive motor can
suffer from any of the afflictions of similar inexpensive permanent magnet
motors found in consumer electronic equipment.  See the section: "Small permanent magnet DC motors".  A broken belt is very common since increased
belt (and tape) tension is used to switch the unit off (hopefully).  Parts can
pop off of their mountings.  Flimsy plastic parts can break.

Opening the case is usually the biggest challenge - screws or snaps may
be used.  Test the motor and its power supply, inspect for broken or
dislocated parts, test the power switch, check and replace the belt if
needed.  That is about it.


  7.87) Vacuum cleaners, electric brooms. and line powered hand vacs


Despite all the hype surrounding vacuum cleaner sales, there isn't much
difference in the basic principles of operation between a $50 and $1,500
model - and the cheaper one may actually work better.

A vacuum cleaner consists of:

1. A cordset - broken wires or damaged plugs are probably the number one
   problem with vacuums as they tend to be dragged around by their tails!
   Therefore, in the case of an apparently dead machine, check this first -
   even just squeezing and bending the wire may produce an instant of
   operation - enough to verify the cause of the problem.

2. A power switch - this may be a simple on/off toggle which can be tested
   with a continuity checker or ohmmeter.  However, fancy machines with
   powered attachments may have interlocks or switches on the attachments
   that can also fail.  Where multiple attachment options are present, do
   your initial troubleshooting with the minimal set as this will eliminate
   potential sources of additional interlock or switch complications.  With
   'microprocessor' or 'computer' controlled vacuum cleaners, the most likely
   problems are not the electronics.

3. A high speed universal motor attached to a centrifugal blower wheel.
   As with any universal motor, a variety of problems are possible: dirt
   (especially with a vacuum cleaner!), lubrication, brushes (carbon),
   open or shorted windings, or bad connections.  See the section: "Problems with universal motors".

4. A belt driven carpet brush (uprights).  The most common mechanical problem
   with these is a broken rubber belt.  (One person who shall remain nameless,
   mistook the end of the broken belt for the tail of a mouse and promptly
   went into hysterics!).  Replacements for these belts are readily available.

5. Power nozzles and other powered attachments.  Some of these are an attempt
   to give canister type vacuum cleaners the power of an upright with its
   directly powered carpet brush.  Generally, these include a much smaller
   motor dedicated to rotating a brush.  Electrical connections are either
   made automatically when the attachment is inserted or on a separate
   cable.  Bad connections, broken belt, or a bad motor are always
   possibilities.

6. A bag to collect dirt.  Vacuum cleaners usually do a poor job of dust
   control despite what the vacuum cleaner companies would have you believe.
   Claims with respect to allergies and other medical conditions are generally
   without any merit unless the machine is specifically designed (and probably
   very expensive) with these conditions in mind.  If the vacuum runs but with
   poor suction, first try replacing the bag.


  7.88) Vacuum cleaner mechanical problems


1. Poor suction - check the dirt bag and replace if more than half full.
   Check for obstructions - wads of dirt, carpet fibers, newspapers, paper
   towels, etc.

2. Poor pickup on floors - broken or worn carpet brush belt.  There should
   be some resistance when turning the carpet brush by hand as you are also
   rotating the main motor shaft.  If there is none, the belt has broken
   and fallen off.  Replacements are readily available.  Take the old one
   and the model number of the vacuum to the store with you as many models
   use somewhat similar but not identical belts and they are generally not
   interchangeable.  To replace the belt on most uprights only requires the
   popping of a couple of retainers and then removing one end of the carpet
   brush to slip the new belt on.

3. Vacuum blows instead of sucks - first confirm that the hose is connected
   to the proper port - some vacuums have easily confused suction and blow
   connections.  Next, check for internal obstructions such as wads of dirt,
   balls of newspaper, or other items that may have been sucked into the
   machine.  Note that it is very unlikely - bordering on the impossible -
   for the motor to have failed in such a way as to be turning in the wrong
   direction (as you might suspect).  Furthermore, even if it did, due to
   the design of the centrifugal blower, it would still suck and not blow.

4. Broken parts - replacements are available for most popular brands from
   appliance repair parts distributors and vacuum/sewing machine repair
   centers.


  7.89) Vacuum cleaner electrical problems


1. Bad cord or plug - number one electrical problem due to the abuse that
   these endure.  Vacuum cleaners are often dragged around and even up and
   down stairs by their tails.  Not surprisingly, the wires inside eventually
   break.  Test with a continuity checker or ohmmeter.  Squeezing or bending
   the cord at the plug or vacuum end may permit a momentary spurt of
   operation (do this with it plugged in and turned on) to confirm this
   diagnosis.

2. Bad power switch - unplug the vacuum and test with a continuity checker
   or ohmmeter.  If jiggling the switch results in erratic operation, a new
   one will be required as well.

3. Bad interlocks or sensors - some high tech vacuum cleaners have air flow
   and bag filled sensors which may go bad or get bent or damaged.  Some
   of these can be tested easily with an ohmmeter but the newest computer
   controlled vacuum cleaners may be more appropriate to be repaired by a
   computer technician!

4. Bad motor - not as common as one might thing.  However, worn carbon
   brushes or dirt wedged in and preventing proper contact is possible.
   See the section: "Problems with universal motors".

5. Bad internal wiring - not likely but always a possibility.


  7.90) Vacuum cleaner hose damage


"We have been quoted a price of $100 to replace the hose on our Panasonic
 (Mc-9537) vacuum cleaner. It has a rip in it; next to the plastic housing 
 where the metal tubing starts.  Does anyone know if there is a more 
 economical way to solve this problem?"

I have always been able to remove the bad section and then graft what is
left back on to the connector.  Without seeing your vacuum, there is no way
to provide specific instructions but that is what creativity is for! :-)
It might take some screws, tape, sealer, etc.

$100 for a plastic hose is obviously one approach manufacturers have of
getting you to buy a new vacuum - most likely from some other manufacturer!

Note: Some vacuum cleaners with power nozzles use the coiled springs of the
hose as the electrical conductors for the power nozzle.  If you end up cutting
the hose to remove a bad section, you will render the power nozzle useless.


  7.91) High tech vacuum cleaners?


Excerpt from a recent NASA Tech Brief:

"The Kirby Company of Cleveland, OH is working to apply NASA technology to
 its line of vacuum cleaners.  Kirby is researching advanced operational
 concepts such as particle flow behavior and vibration, which are critical
 to vacuum cleaner performance.  Nozzle tests using what is called Stereo
 Imaging Velocity will allow researchers to accurately characterize fluid
 and air experiments.  Kirby is also using holography equipment to study
 vibration modes of jet engine fans."

I suppose there will be degree-credit university courses in the operation
of these space age vacuums as well! --- sam


  7.92) Dustbusters(tm) and other battery powered hand vacs


These relatively low suction battery powered hand vacuums have caught on
due to their convenience - certainly not their stellar cleaning ability!

A NiCd battery pack powers a small DC permanent magnet motor and centrifugal
blower.  A simple momentary pushbutton power switch provides convenient
on/off control.

Aside from obvious dirt or liquid getting inside, the most common problems
occur with respect to the battery pack.  If left unused and unplugged for
a long time, individual NiCd cells may fail shorted and not take or hold
a charge when the adapter is not plugged back into the wall socket.  Sluggish
operation is often due to a single NiCd cell failing in this way.

See the appropriate sections on "Batteries" and "Motors" for more information.


  7.93) Dustbusters left on continuous charge and battery problems


The low current trickle charger supplied with these battery operated hand-vacs
allow Dustbusters and similar products to be be left on continuous charge so
long as they are then not allowed to self discharge totally (left on a shelf
unplugged for a long time).  Older ones, in particular, may develop shorted
cells if allowed to totally discharge.  I have one which I picked up at a
garage sale where I had to zap cells to clear a shorts.  However, it has been
fine for several years now being on continuous charge - only removed when used.

While replacing only selected cells in any battery operated appliance is
generally not recommended for best reliability, it will almost certainly
be much cheaper to find another identical unit at a garage sale and make
one good unit out of the batteries that will still hold a charge.  It is
better to replace them all but this would cost you as much as a new
Dustbuster.

The NiCd cells are soldered in (at least in all those I have seen) so
replacement is not as easy as changing the batteries in a flashlight but
it can be done.  If swapping cells in from another similar unit, cut the
solder tabs halfway between the cells and then solder the tabs rather than
to the cells themselves if at all possible.  Don't mess up the polarities!

In the case of genuine Dustbusters, where a new battery is needed and you
don't have a source of transplant organs, it may be better to buy the
replacement cells directly from Black and Decker. They don't gouge you on NiCd
replacements.  B&D is actually cheaper than Radio Shack, you know they are the
correct size and capacity, and the cells come with tabs ready to install.
They'll even take your old NiCds for proper re-cycling.


  7.94) Floor polishers


A relatively large universal motor powers a set of counter-rotating
padded wheels.  Only electrical parts to fail: plug, cord, power switch,
motor.  Gears, shafts, and other mechanical parts may break.


  7.95) Heating pads


Heating pads are simply a very fine wire heating element covered in thick
insulation and then sealed inside a waterproof flexible plastic cover.
Internal thermostats prevent overheating and regulate the temperature.
The hand control usually provides 3 heat settings by switching in different
sections of the heating element and/or just selecting which thermostat is used.

There are no serviceable parts inside the sealed cover - forget it as any
repair would represent a safety hazard.  The control unit may develop bad
or worn switches but even this is somewhat unlikely.  It is possible to
disassemble the control to check for these.  You may find a resistor or diode
in the control - check these also.  With the control open, test the wiring to
the pad itself for low resistance (a few hundred ohms) between any pair of
wires).  If these test open, it is time for a new heating pad.  Otherwise,
check the plug, cord, and control switches.

Extended operationg especially at HIGH, or with no way for the heat to escape,
may accelerate deterioration inside the sealed rubber cover.  One-time thermal
fuses may blow as well resulting in a dead heating pad.  One interesting note:
Despite being very well sealed, my post mortems on broken heating pads have
shown one possible failure to be caused by corrosion of the internal wiring
connections after many years of use.


  7.96) Electric blankets


As with heating pads, the only serviceable parts are the controller and
cordset.  The blanket itself is effectively sealed against any repair
so that any damage that might impact safety will necessitate replacement.

Older style controllers used a bimetal thermostat which actually sensed
air temperature, not under-cover conditions.  This, it turns out, is a
decent measurement and does a reasonable job of maintaining a comfortable
heat setting.  Such controllers produced those annoying clicks every couple
of minutes as the thermostat cycled.  Problems with the plug, cord, power
switch, and thermostat contacts are possible.  The entire controller usually
unplugs and can be replaced as a unit as well.

Newer designs use solid state controls and do away with the switch
contacts - and the noise.  Aside from the plug and cord, troubleshooting
of a faulty or erratic temperature control is beyond the scope of this
manual.


  7.97) Humidifiers


There are three common types:

1. Wet pad or drum - a fan blows air across a stationary or rotating
   material which is water soaked.  There can be mechanical problems
   with the fan or drum motor or electrical problems with the plug,
   cord, power switch, or humidistat.

2. Spray - an electrically operated valve controls water sprayed from
   a fine nozzle.  Problems can occur with the solenoid valve (test the
   coil with an ohmmeter), humidistat, or wiring.  The fine orifice may
   get clogged by particles circulating in the water or hard water deposits.
   In cleaning, use only soft materials like pointy bits of wood or plastic
   to avoid enlarging the hole in the nozzle.

3. Ultrasonic - a high frequency power oscillator drives a piezo electric
   'nebulizer' which (with the aid of a small fan) literally throws fine
   droplets of water out into the room.  Problems with the actual ultrasonic
   circuitry is beyond the scope of this manual but other common failures
   can be dealt with like plug, cord, fan motor, control switches, wiring,
   etc.  However, if everything appears to working but there is no mist
   from the output port, it is likely that the ultrasonic circuitry has
   failed.  See the section: "Ultrasonic humidifiers" for more details.


  7.98) Ultrasonic humidifiers


(From: Filip "I'll buy a vowel" Gieszczykiewicz (filipg@repairfaq.org)).

The components of the typical $45 unit are:

* Piezo transducer + electronics (usually in a metal cage - we are talking
  line current here - not safe!).

* Small blower/fan.

* Float-switch.

* Water tank.

The piezo transducer sets up a standing wave on the surface of the water pool.
The level is sensed with a float-switch to ensure no dry-running (kills the
piezo) and the blower/fan propels the tiny water droplets out of the cavity.
A few manufacturers are nice enough to include a silly air filter to keep any
major dust out of the 'output' - do clean/check that once in a while.

Common problems:

* Low output:

  - Minerals from water deposited on surface(s) of the water pool - including
    the piezo. This disrupts/changes the resonance/output of the piezo - and
    you see the effect.

  - Clogged air filter - there should be a little 'trap door' somewhere
    on the case with a little grill. Pop it out and wash the filter found
    therein. Replace.

  - Driver of the piezo going down that hill. Time to get another one or
    look for the warranty card if it applies.
 
CAUTION: Unless you know what you are doing (and have gotten shocked a
few times in your life) DO NOT play with the piezo driver module. Most
run at line voltage with sometimes 100+V on heatsinks - which are live.

* No output:

  - Dead piezo driver - get a new unit unless under warranty.

  - Dead wire or float-switch or humidity switch or 'volume'... that 
    should be easy - use an ohmmeter and look for shorts/opens/resistance.

  - Dead fan - should still have mist - just none of it getting out.

  - No power in the outlet you're using ;-)

Note: piezo's in general are driven with voltage, as opposed to current. This
explains why you can expect high voltages - even in otherwise low-voltage
circuits. Case in point: the Polaroid ultrasonic sonar modules.


  7.99) Ultrasonic waterfalls?


I don't suppose you are likely to encounter these but if you do, servicing
procedures will be similar to those described in the section: "Ultrasonic humidifiers".

(From: Roger Vaught (vaurw@onramp.net)).

At a local shop they sell small water fall displays made from limestone in a
marble catch basin.  These are made in China. They use a small water pump for
the flow.  

When I first saw one I thought the store had placed dry ice in the cavity
where the water emerged as there was a constant stream of cloud flowing from
it.  Very impressive. It turns out they use the ultrasonic piezo gizmo to make
the cloud.  The driver is a small 3 X 5 X 3 inch box with a control knob on
top.  If you look into the cavity you can see the piezo plate and a small red
LED.  The water periodically erupts into vapor.  I haven't been able to get a
close look at the driver so I can't tell where it is made or if there is a
product name or manufacturer.  They will sell that part of it for $150! 


  7.100) Ultrasonic cleaners


Ultrasonic cleaning is a means of removing dirt and surface contamination from
intricate and/or delicate parts using powerful high frequency sound waves in
a liquid (water/detergent/solvent) bath.

An ultrasonic cleaner contains a power oscillator driving a large piezoelectric
transducer under the cleaning tank.  Depending on capacity, these can be quite
massive.

A typical circuit is shown below.  This is from a Branson Model 41-4000 which
is typical of a small consumer grade unit.

               R1        D1
 H o------/\/\-------|>|----------+
         1, 1/2 W  EDA456         |
               C1         D2      |
          +----||----+----|>|-----+
          |  .1 uF   |  EDA456    |  2  
          |  200 V   |      +-----+---+ T1      +---+------->>------+
          |    R2    |     _|_ C2      )||  o 4 |   |               |
          +---/\/\---+     --- .8 uF D )|| +----+   |               |
          |   22K          _|_ 200 V   )||(         +               |
          |   1 W           -      1 o )||(          )||           _|_
          +-----------------+---------+ ||( O        )|| L1        _x_ PT1
          |           R3    |        7  ||(          )||            |
          |      +---/\/\---+   +-----+ ||( 5       +               |
         C \|    | 10K, 1 W     |    F )|| +---+    |               |
       Q1   |--+-+--------------+  6 o )||     |    |               |
         E /|  |  D3     R4       +---+        +----+------->>------+
          |    +--|<|---/\/\--+  _|_
          |           47, 1 W |  ---       Input: 115 VAC, 50/60 Hz
          |                   |   |        Output: 460 VAC, pulsed 80 KHz
 N o------+-------------------+---+

The power transistor (Q1) and its associated components form an self excited
driver for the piezo-transducer (PT1).  I do not have specs on Q1 but based on
the circuit, it probably has a Vceo rating of at least 500 V and power rating
of at least 50 W.

Two windings on the transformer (T1, which is wound on a toroidal ferrite
core) provide drive (D) and feedback (F) respectively.  L1 along with the
inherent capacitance of PT1 tunes the output circuit for maximum amplitude.

The output of this (and similar units) are bursts of high frequency (10s to
100s of KHz) acoustic waves at a 60 Hz repetition rate.  The characteristic
sound these ultrasonic cleaners make during operation is due to the effects
of the bursts occuring at 60 Hz since you cannot actually hear the ultrasonic
frequencies they use.

The frequency of the ultrasound is approximately 80 KHz for this unit with a
maximum amplitude of about 460 VAC RMS (1,300 V p-p) for a 115 VAC input.

WARNING: Do not run the device with an empty tank since it expects to have
a proper load.  Do not touch the bottom of the tank and avoid putting your
paws into the cleaning solution while the power is on.  I don't know what,
if any, long term effects there may be but it isn't worth taking chances.
The effects definitely feel strange.

Where the device doesn't oscillate (it appears as dead as a door-nail), first
check for obvious failures such as bad connections and cracked, scorched, or
obliterated parts.

To get inside probably requires removing the bottom cover (after pulling the
plug and disposing of the cleaning solution!).

CAUTION: Confirm that all large capacitors are discharged before touching
anything inside!

The semiconductors (Q1, D1, D2, D3) can be tested for shorts with a multimeter
(see the document: "Basic Testing of Semiconductor Devices".

The transformer (T1) or inductor (L1) could have internal short circuits
preventing proper operation and/or blowing other parts due to excessive load
but this isn't kind of failure likely as you might think.  However, where all
the other parts test good but the cleaning action appears weak without any
overheating, a L1 could be defective (open or other bad connections) detuning
the output circuit.


  7.101) Dehumidifiers


Electric dehumidifiers use a refrigeration system to cool a set of coils
which condenses water vapor.  The heat is then returned to the air and
it is returned back to the room.  On the surface, this seems like an
incredible waste of energy - cooling the air and heating it back up -
but it is very effective at removing moisture.  A typical large dehumidifier
will condense something like 30 pints in 24 hours - which, unless you have
it located over a drain - then needs to be dumped by hand.

There is supposed to be a cutoff (float) switch to stop the dehumidifier
when the container is full.  Hopefully, it works (and you didn't neglect
to install it when the unit was new!)

Common problems with these units are often related to the fan, humidistat,
or just plain dirt - which tends to collect on the cooling coils.  The
sealed refrigeration system is generally quite reliable and will never need
attention.

An annual cleaning of the coils with a soft brush and a damp cloth is a good
idea.  If the fan has lubrication holes, a couple of drops (but no more) of
electric motor oil should be added at the same time.

The fan uses an induction motor - shaded pole probably - and may require
cleaning and lubrication.  See the section: "Problems with induction motors".

The humidistat may develop dirty or worn contacts or the humidity sensing
material - sort of like a hot dog wrapper - may break.  If you don't hear
a click while rotating the control through its entire range, this may have
happened.  If you hear the click - and the dehumidifier is plugged into
a live outlet - but nothing happens, then there is probably a problem in
the wiring.  If just the fan turns on but not the compressor, (and you have
waited at least 5 minutes for the internal pressures to equalize after
stopping the unit) then there may be a problem with the compressor or its
starting relay (especially if the lights dim indicating a high current).

A very low line voltage condition could also prevent a refrigeration system
from starting or result in overheating and cycling.  A sluggish slow rotating
or seized fan, or excessive dirt buildup may also lead to overheating and
short cycling.

A unit that ices up may simply be running when it is too cold (and you don't
really need it anyway).  Dehumidifiers may include sensors to detect ice
buildup and/or shut off if the temperature drops below about 60 degrees F.


  7.102) Garbage disposals


A garbage disposal is just an AC induction motor driving a set of centrifugal
hammers (they use to use sharp cutters but these were even more dangerous).
The cutters throw the food against an outer ring with relatively sharp slots
which break up the food into particles that can be handled (hopefully) by
the waste system.  However, always use generous amounts of cold water (which
helps to cool the motor as well) and let it run for a while after there is
nothing left in the disposal and it has quieted down.  This will assure a
trouble free drain.  Otherwise, you may be inviting your friendly plumber
over for a visit!

Common problems with garbage disposals relate to three areas:

* Something stuck in grinding chamber - disposal hums or trips internal
  protector (red button) or main fuse or circuit breaker.  Unplug disposal!
  Then use the wrench (or appropriate size hex wrench) that came with the
  disposal to work rotor back and forth from bottom.  If there is no hole
  for a wrench (or you misplaced yours), try a broom handle from above but
  NEVER put your hand in to try to unjam it (there are still relatively
  sharp parts involved).   With the disposer unplugged, you can carefully
  reach in and feel for any objects that may be stuck or which cannot be
  broken up by the grinding action (like forks, toys, rocks, beef bones,
  etc.) and fish these out.  Once free, restore power (if needed) and/or
  reset red button ((usually underneath the motor housing - you may have
  to wait a couple minutes until it will reset (click and stay in).  Then
  run the unit with full flow of cold water for a couple of minutes to clear
  anything remaining from the grinding chamber and plumbing.

* Motor - although these only run for a few seconds a day, motor problems
  including shorted windings or defective rotors are possible.   Assuming
  rotor turns freely, these may include a hum but no movement, repeated
  blown fuses or tripped circuit breakers, or any burning smells.

* Leaking shaft seal - probably what causes most disposals to ultimately
  fail.  The upper seal develops a slight leak which permits water to enter
  the motor housing damaging the bearing and causing electrical problems.
  Symptoms include seized rotor, excessive noise or vibration,  actual
  water leaking from inside the motor housing, burning smells, etc.

* Power switch (built into batch feed models) - wall switches can go bad
  like any other application.  The built in magnetic or microswitch in a
  batch feed disposal can also fail.  Intermittent or no operation may
  result.

* Drain blockage - disposal runs but water doesn't get pumped out of sink
  or backs up.  Use plumber's helper (plunger) or better yet, remove U-trap
  under sink and use a plumber's (steel) snake to clear blockage in the
  waste pipe.  NEVER NEVER use anything caustic!!!  First of all, it will
  not likely work (don't believe those ads!).  More importantly, it will
  leave a dangerous corrosive mess behind for you or the plumber to clean
  up.  The plunger or snake will work unless the blockage is so impacted
  or in a bad location (like a sharp bend) in which case a professional
  will need to be called in any case.

Unless you are the truly die-hard doit-yourselfer, repair of disposals is
probably not a good use of your time.  The ultimate reliability of all
but the most obvious and simple repairs is usually unknown and could be
very short.  However, other than time, there is nothing to be lost by
at least investigating the source of the problem.


  7.103) Garbage disposal pops reset button but nothing blocked


Even if nothing is stuck in it, is the rotor free - not too tight?  If you
have that little wrench that comes with many disposers, you should be able
to turn the rotor relatively easily (I would say about 1 foot-pound of
torque or less if your arm is calibrated).  A tight bearing may be the
result of a shaft seal leak - see the next section: "Garbage disposal seizes repeatedly".

The red reset button is a circuit breaker.  Either the motor is drawing
too much current due to a shorted winding or a tight bearing or the breaker
is faulty.  Without an ammeter, it will be tough to determine which it
is unless the rotor is obviously too tight.

If you have a clamp-on ammeter, the current while the motor is running
should be less than the nameplate value (startup will be higher).  If
it is too high, than there is likely a problem with the motor.  As an
alternate you could try bypassing the circuit breaker with a slow blow
fuse of the same rating as the breaker (it hopefully will be marked) or
a replacement breaker (from another dead garbage disposal!.  If this
allows the disposer to run continuously your original little circuit
breaker is bad.  These should be replaceable.

If the bearings are tight, it is probably not worth fixing unless it is
due to something stuck between the grinding disk and the base.  Attempting
to disassemble the entire unit is likely to result in a leak at the top
bearing though with care, it is possible to do this successfully.


  7.104) Garbage disposal is stuck - hums but does not turn


"I need help.  Our garbage disposal is stuck.  It hums but doesn't turn.  If I
 leave it on for more than a few seconds it trips the circuit breaker on the unit.
 Any tips on how to solve this shy of buying a new unit?  The unit is 7 years old."

"I have an ISE In-Sink-Erator (tm), Badger I model.  I tried turning mine on a
 few minutes ago, the motor started then stopped and now nothing happens when I
 flip the wall switch, not even a click."

Of course, first make sure there is nothing jamming it - use a flashlight
to inspect for bits of bone, peach pits, china, glass, metal, etc.  Even a
tiny piece - pea size - can get stuck between the rotating disk and the
shredder ring.  WITH THE DISPOSAL UNPLUGGED OR THE BREAKER OFF, work the
the rotor back and forth using the hex wrench that came with the unit or
a replacement (if your unit is of the type that accepts a wrench from below.
If it is not of this type, use the infamous broom handle from above.)

The internal circuit breaker will trip to protect the motor if the rotor
doesn't turn.  Turn off the wall switch, wait a few minutes for the circuit
breaker and motor to cool, and then press the red reset button underneath
the disposal.  If it does not stay in, then you didn't wait long enough or
the circuit breaker itself is defective.  Then, turn on the water and try
the wall switch again (in-sink switch if it is a batch feed model).

Assuming it is still tight with nothing stuck inside and/or jams repeatedly:

(From: Rob-L (rob-l@superlink.net)).

That's about how long it takes for the nut to rust away on the shredder
disc of Insinkerator/Sears units.  My comments will address ISE/Sears
deluxe models with the stainless disc, for those who might have one.

When the nut/washer rusts away, the disc will wobble and get jammed.  With
the power off, try to rock the disc inside the unit. You might need to
wiggle the motor shaft with a 1/4" hex wrench under the unit.  

If you can free things up, and the disc can be rocked, it's the
nut/washer.  When that goes, so does the gasket, and unfortunately it
requires total disassembly of the grinding chamber to replace the little
gasket, because the disc will not come out otherwise.  And if you don't
replace the gasket, water/gunk will run down the motor shaft and into the
motor. When those units go, you're better off to get a new disposer.  

I think they intentionally use a non-stainless steel nut, because
otherwise the units would last a long time.  Even the replacement nuts
will corrode.  The motor shaft will also corrode, but not as fast as the
nut.  With a stainless shaft and nut/washer, the disposer would give many
more years of service.  And that's why they don't make 'em that way. :)

One part that is worth replacing is the mounting gasket.  It's the part
with the flaps that you feed things through.  It gets cut-up and damaged
by chlorine from sink cleaning or dishwasher discharge. (brittle, rough) 
It's a $4 part, usually available at Home Depot next to the new disposers,
and it slips on in a matter of minutes -- you just disconnect the trap,
then drop the disposer down by undoing the retaining ring.  Swap the
gasket, re-attach things, and your sink drain looks brand new.

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Written by Samuel M. Goldwasser. | [mailto]. The most recent version is available on the WWW server http://www.repairfaq.org/ [Copyright] [Disclaimer]