Hi all,

finally tore down my dishwasher today after getting sick of doing dishes
by hand and striking out on Craigslist. For those of you that missed
the first installment, a transformer exploded a couple streets over late
Sunday night or early Monday morning and blowed up some stuff in my
house (a surge strip, an electrostatic air filter, and my dishwasher.)
I've already ordered (online) a new power supply for the air filter, and
replaced the surge strip and the TVSS breaker that was in my main panel
(the "protected" light was out on one leg.)

Turns out that the failure of the dishwasher looks exactly like the
failure of the air filter; on the power supply board there is a
orangeish-yellow dsc-shaped component soldered onto the board about 1/2"
in diameter, and it appears to have failed with extreme prejudice. Am I
correct in assuming that this is a MOV? Could I just do a component
level repair of this rather than replace the whole board? I really hate
this dishwasher and don't want to spend a lot of money on it. If this
is a MOV, is value important, or simply "bigger is better?" I'm sorry
for the dumb questions, but I'm not particularly electronically
knowledgeable (made it through two EE classes in college and I think
I've forgotten most of what I learned) just trying to get this back up
and running. If Trible's had still been open by the time I got it
apart, I probably wouldn't be asking the question, but if there's a
chance I could fix it today...

thanks,

nate

--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel

Nate Nagel wrote:
Hi all,

finally tore down my dishwasher today after getting sick of doing dishes
by hand and striking out on Craigslist. For those of you that missed
the first installment, a transformer exploded a couple streets over late
Sunday night or early Monday morning and blowed up some stuff in my
house (a surge strip, an electrostatic air filter, and my dishwasher.)
I've already ordered (online) a new power supply for the air filter, and
replaced the surge strip and the TVSS breaker that was in my main panel
(the "protected" light was out on one leg.)

Turns out that the failure of the dishwasher looks exactly like the
failure of the air filter; on the power supply board there is a
orangeish-yellow dsc-shaped component soldered onto the board about 1/2"
in diameter, and it appears to have failed with extreme prejudice. Am I
correct in assuming that this is a MOV? Could I just do a component
level repair of this rather than replace the whole board? I really hate
this dishwasher and don't want to spend a lot of money on it. If this
is a MOV, is value important, or simply "bigger is better?" I'm sorry
for the dumb questions, but I'm not particularly electronically
knowledgeable (made it through two EE classes in college and I think
I've forgotten most of what I learned) just trying to get this back up
and running. If Trible's had still been open by the time I got it
apart, I probably wouldn't be asking the question, but if there's a
chance I could fix it today...

thanks,

nate


Never mind... I think I just answered my own question. The MOV, which
I'm pretty sure what I'm looking at, in the dishwasher, shows no
continuity when probed with my trusty Fluke, so that should not prevent
the dishwasher from functioning (but *would* leave it without surge
protection.) So I ASSume that something else is also fried on that board.

nate

--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel

On Sat, 17 May 2008 18:17:54 -0400, Nate Nagel wrote:

Never mind... I think I just answered my own question. The MOV, which
I'm pretty sure what I'm looking at, in the dishwasher, shows no
continuity when probed with my trusty Fluke, so that should not prevent

An MOV will never show continuity when measured with a multimeter. The
resistance is nearly infinite until the breakdown voltage is reached,
then it drops to zero. To test an MOV, you need a voltage source greater
than the breakdown voltage, and a series resistor so the MOV won't damage
your power sourcde.

Nate Nagel writes:

Never mind... I think I just answered my own question. The MOV, which
I'm pretty sure what I'm looking at, in the dishwasher, shows no
continuity when probed with my trusty Fluke, so that should not prevent
the dishwasher from functioning (but *would* leave it without surge
protection.) So I ASSume that something else is also fried on that board.

Check for a blown fuse. Sometimes the MOV is downstream from a fuse,
with the intent that the MOV will absorb small surges, and blow the fuse
on large surges that the MOV cannot absorb. If you're lucky, replacing
the fuse might have it running again.

But more likely something else is fried. If the MOV is the only thing
destroyed, the rest of the circuit would work, and you could just
replace the MOV at your leisure. The fact that the circuit doesn't work
suggests that the overvoltage was too much for the MOV and it probably
took out one or more other voltage-sensitive devices too.

Dave

"Nate Nagel" wrote in message
...
Hi all,

finally tore down my dishwasher today after getting sick of doing dishes
by hand and striking out on Craigslist. For those of you that missed the
first installment, a transformer exploded a couple streets over late
Sunday night or early Monday morning and blowed up some stuff in my house
(a surge strip, an electrostatic air filter, and my dishwasher.) I've
already ordered (online) a new power supply for the air filter, and
replaced the surge strip and the TVSS breaker that was in my main panel
(the "protected" light was out on one leg.)

Turns out that the failure of the dishwasher looks exactly like the
failure of the air filter; on the power supply board there is a
orangeish-yellow dsc-shaped component soldered onto the board about 1/2"
in diameter, and it appears to have failed with extreme prejudice. Am I
correct in assuming that this is a MOV? Could I just do a component level
repair of this rather than replace the whole board? I really hate this
dishwasher and don't want to spend a lot of money on it. If this is a
MOV, is value important, or simply "bigger is better?" I'm sorry for the
dumb questions, but I'm not particularly electronically knowledgeable
(made it through two EE classes in college and I think I've forgotten most
of what I learned) just trying to get this back up and running. If
Trible's had still been open by the time I got it apart, I probably
wouldn't be asking the question, but if there's a chance I could fix it
today...


If it is the MOV, you can just cut it out of the circuit and try the washer.
The mov is basically an open circuit and shorts out when a voltage higher
than what it is rated for hits it, then opens back up when the voltage
returns to normal. This is to protect the circuit board from voltage
surges. If they get hit with too big of a surge they may blow off the
board.

If the washer works, feel free to use it, but replace the mov as soon as
possiable incase you get another surge.
You may want to unplug it or cut off the circuit breaker when it is not in
use, especially if a storm is near.

The bigger is beter is still in effect. Keep the voltage rating the same,
but you can go up in the power rating.

"Ralph Mowery" wrote in
m:


"Nate Nagel" wrote in message
...
Hi all,

finally tore down my dishwasher today after getting sick of doing
dishes by hand and striking out on Craigslist. For those of you that
missed the first installment, a transformer exploded a couple streets
over late Sunday night or early Monday morning and blowed up some
stuff in my house (a surge strip, an electrostatic air filter, and my
dishwasher.) I've already ordered (online) a new power supply for the
air filter, and replaced the surge strip and the TVSS breaker that
was in my main panel (the "protected" light was out on one leg.)

Turns out that the failure of the dishwasher looks exactly like the
failure of the air filter; on the power supply board there is a
orangeish-yellow dsc-shaped component soldered onto the board about
1/2" in diameter, and it appears to have failed with extreme
prejudice. Am I correct in assuming that this is a MOV? Could I
just do a component level repair of this rather than replace the
whole board? I really hate this dishwasher and don't want to spend a
lot of money on it. If this is a MOV, is value important, or simply
"bigger is better?" I'm sorry for the dumb questions, but I'm not
particularly electronically knowledgeable (made it through two EE
classes in college and I think I've forgotten most of what I learned)
just trying to get this back up and running. If Trible's had still
been open by the time I got it apart, I probably wouldn't be asking
the question, but if there's a chance I could fix it today...


If it is the MOV, you can just cut it out of the circuit and try the
washer.

Usually,there is a fuse inbetween the MOV and line source,so the fuse opens
whne the MOV shunts the surge/spike to ground. I've seen MOVs split
open,and PCB traces vaporize,and the power supply still work when the fuse
was replaced and trace repaired.
Sometimes the switcher transistor/FET gets blown,too.


The mov is basically an open circuit and shorts out when a
voltage higher than what it is rated for hits it, then opens back up
when the voltage returns to normal. This is to protect the circuit
board from voltage surges. If they get hit with too big of a surge
they may blow off the board.

If the washer works, feel free to use it, but replace the mov as soon
as possiable incase you get another surge.
You may want to unplug it or cut off the circuit breaker when it is
not in use, especially if a storm is near.

The bigger is beter is still in effect. Keep the voltage rating the
same, but you can go up in the power rating.





MOVs usually are marked 130Vxx or 250Vxx,yours probably is a 130V MOV,and
they come in varying current sizes.

--
Jim Yanik
jyanik
at
kua.net

Nate Nagel wrote:
Hi all,

finally tore down my dishwasher today after getting sick of doing
dishes by hand and striking out on Craigslist. For those of you that
missed the first installment, a transformer exploded a couple streets
over late Sunday night or early Monday morning and blowed up some
stuff in my house (a surge strip, an electrostatic air filter, and my
dishwasher.) I've already ordered (online) a new power supply for the
air filter, and replaced the surge strip and the TVSS breaker that
was in my main panel (the "protected" light was out on one leg.)

Turns out that the failure of the dishwasher looks exactly like the
failure of the air filter; on the power supply board there is a
orangeish-yellow dsc-shaped component soldered onto the board about
1/2" in diameter, and it appears to have failed with extreme
prejudice. Am I correct in assuming that this is a MOV? Could I
just do a component level repair of this rather than replace the
whole board? I really hate this dishwasher and don't want to spend a
lot of money on it. If this is a MOV, is value important, or simply
"bigger is better?" I'm sorry for the dumb questions, but I'm not
particularly electronically knowledgeable (made it through two EE
classes in college and I think I've forgotten most of what I learned)
just trying to get this back up and running. If Trible's had still
been open by the time I got it apart, I probably wouldn't be asking
the question, but if there's a chance I could fix it today...


It could be a ceramic disk capacitor.

Does it SAY anything on the component ("MOV" would be a clue, so would ".01
mfd")

HeyBub wrote:
Nate Nagel wrote:

Hi all,

finally tore down my dishwasher today after getting sick of doing
dishes by hand and striking out on Craigslist. For those of you that
missed the first installment, a transformer exploded a couple streets
over late Sunday night or early Monday morning and blowed up some
stuff in my house (a surge strip, an electrostatic air filter, and my
dishwasher.) I've already ordered (online) a new power supply for the
air filter, and replaced the surge strip and the TVSS breaker that
was in my main panel (the "protected" light was out on one leg.)

Turns out that the failure of the dishwasher looks exactly like the
failure of the air filter; on the power supply board there is a
orangeish-yellow dsc-shaped component soldered onto the board about
1/2" in diameter, and it appears to have failed with extreme
prejudice. Am I correct in assuming that this is a MOV? Could I
just do a component level repair of this rather than replace the
whole board? I really hate this dishwasher and don't want to spend a
lot of money on it. If this is a MOV, is value important, or simply
"bigger is better?" I'm sorry for the dumb questions, but I'm not
particularly electronically knowledgeable (made it through two EE
classes in college and I think I've forgotten most of what I learned)
just trying to get this back up and running. If Trible's had still
been open by the time I got it apart, I probably wouldn't be asking
the question, but if there's a chance I could fix it today...



It could be a ceramic disk capacitor.

Does it SAY anything on the component ("MOV" would be a clue, so would ".01
mfd")



If it does, I can't read it under the blackenedness

SWMBO was told by the power company not to throw anything out for claims
purposes so if I'm not sure what it is I'm not cleaning/messing with it...

nate

--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel