My 2 y/o Panasonic NN-T664 microwave (1300W inverter design) blew a fuse,
apparently due to the fuse simply wearing out. All else seems normal,
including door switches.

The first symptom was loss of display, but unplugging/re-plugging the power
cord restored that briefly. Then, I removed and reinstalled the original
fuse and got another burst of life. The fuse was intermittent for a day
before finally going open.

The Panasonic factory fuse was an ABC 125/250V 18A ceramic, but I can only
find 15A or 20A versions in hardware or electronics stores. Even online,
18A fuses are elusive. Maximum current in this oven is stated as 12.7A at
1,460 watts. So far the 15A fuse I replaced it with has held up after a two
days.

Does anyone know why Panasonic uses a rare 18A fuse (vs. 15A or 20A) and
how long a 15A fuse should last?

Jack

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Jack wrote:
My 2 y/o Panasonic NN-T664 microwave (1300W inverter design) blew a fuse,
apparently due to the fuse simply wearing out. All else seems normal,
including door switches.

The first symptom was loss of display, but unplugging/re-plugging the power
cord restored that briefly. Then, I removed and reinstalled the original
fuse and got another burst of life. The fuse was intermittent for a day
before finally going open.

The Panasonic factory fuse was an ABC 125/250V 18A ceramic, but I can only
find 15A or 20A versions in hardware or electronics stores. Even online,
18A fuses are elusive. Maximum current in this oven is stated as 12.7A at
1,460 watts. So far the 15A fuse I replaced it with has held up after a two
days.

Does anyone know why Panasonic uses a rare 18A fuse (vs. 15A or 20A) and
how long a 15A fuse should last?

Jack

Hi Jack...

Here's a couple...

http://www.circuitprotection.ca/MFsearch.php

Take care.

Ken

Response inserted at corresponding lines - sorry for inconveniences

Jack wrote:

My 2 y/o Panasonic NN-T664 microwave (1300W inverter design) blew a fuse,
apparently due to the fuse simply wearing out. All else seems normal,
including door switches.

The first symptom was loss of display, but unplugging/re-plugging the
power cord restored that briefly.

The lossy display might point out to a worn-out electrolytic capacitor in
either the power-supply or the control-circuitry


--
Sincerely

Ruediger

In article , Jack wrote:
My 2 y/o Panasonic NN-T664 microwave (1300W inverter design) blew a fuse,
apparently due to the fuse simply wearing out. All else seems normal,
including door switches.

The first symptom was loss of display, but unplugging/re-plugging the power
cord restored that briefly. Then, I removed and reinstalled the original
fuse and got another burst of life. The fuse was intermittent for a day
before finally going open.

The Panasonic factory fuse was an ABC 125/250V 18A ceramic, but I can only
find 15A or 20A versions in hardware or electronics stores. Even online,
18A fuses are elusive. Maximum current in this oven is stated as 12.7A at
1,460 watts. So far the 15A fuse I replaced it with has held up after a two
days.

Does anyone know why Panasonic uses a rare 18A fuse (vs. 15A or 20A) and
how long a 15A fuse should last?

If it were my own, I would use the 20.
Its funny that the commercial version is only rated about 1300 watts out but
has higher current input. Different ways of rating power I guess.
One power rating is hotter than another I guess. The commercial cost
about 5 times more !!!!!!!!!!!!!!!

greg

"Jack" wrote in message
...
My 2 y/o Panasonic NN-T664 microwave (1300W inverter design) blew a fuse,
apparently due to the fuse simply wearing out. All else seems normal,
including door switches.

The first symptom was loss of display, but unplugging/re-plugging the
power
cord restored that briefly. Then, I removed and reinstalled the original
fuse and got another burst of life. The fuse was intermittent for a day
before finally going open.

The Panasonic factory fuse was an ABC 125/250V 18A ceramic, but I can only
find 15A or 20A versions in hardware or electronics stores. Even online,
18A fuses are elusive. Maximum current in this oven is stated as 12.7A at
1,460 watts. So far the 15A fuse I replaced it with has held up after a
two
days.

Does anyone know why Panasonic uses a rare 18A fuse (vs. 15A or 20A) and
how long a 15A fuse should last?

If the current is only 13 amps or less the fuse should last forever.
Sometimes they will get 'tired' and just blow. A fuse develops heat and
melts . When operated near its rated current they just get hot and do what
I call a 'sag out' after a period of time. As most homes have either a 15
or 20 amp fuse/braker the fuse in the microwave is almost not needed as the
house circuit would go about the same time or before if some other devices
are connected to the same circuit.

I work for a large complex and we have many kinds of fuses used in our
equipment. One odd ball is a 63 miliamp fuse for 250 volts. Another is a
6.5 amp one. A few years back a repersenative from a fuse company put on a
talk. At one time the fuse company made many kinds and used that as a
selling point. Now they are telling us that one fuse will replace about ten
types they used to make. That is now their selling point.

I would sitck in the 15 amp fuse and if it holds tehn use the micro wave.
If it blows in a few weeks then go to the 20 amp fuse.

Ruediger wrote in
:

Response inserted at corresponding lines - sorry for inconveniences

Jack wrote:

My 2 y/o Panasonic NN-T664 microwave (1300W inverter design) blew a
fuse, apparently due to the fuse simply wearing out. All else seems
normal, including door switches.

The first symptom was loss of display, but unplugging/re-plugging the
power cord restored that briefly.

The lossy display might point out to a worn-out electrolytic capacitor
in either the power-supply or the control-circuitry

I'm pretty sure in this case the fuse just "sagged" after two years, as
someone else put it. The display was either on or off, not variable,
although the green LEDs were always fairly dim from day one (my only
complaint with the unit). That could be a separate issue.

Jack

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"Ralph Mowery" wrote in
nk.net:

If the current is only 13 amps or less the fuse should last forever.
Sometimes they will get 'tired' and just blow. A fuse develops heat
and melts . When operated near its rated current they just get hot
and do what I call a 'sag out' after a period of time. As most homes
have either a 15 or 20 amp fuse/braker the fuse in the microwave is
almost not needed as the house circuit would go about the same time or
before if some other devices are connected to the same circuit.

Good point. It's as if Panasonic wants to save the oven just before the
whole branch goes down! I will put my faith in the 15A fuse.

Jack

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Panasonic had an issue with the 18 amp fuses in a series of their microwave
ovens. The fuses were not up to spec and they would go intermittent or blow
for no reason. Panasonic recommends the fuse be replaced with a 20 amp
fuse.


"Ken Weitzel" wrote in message
news:sy2dg.185159$P01.140927@pd7tw3no...


Jack wrote:
My 2 y/o Panasonic NN-T664 microwave (1300W inverter design) blew a
fuse,
apparently due to the fuse simply wearing out. All else seems normal,
including door switches.

The first symptom was loss of display, but unplugging/re-plugging the
power
cord restored that briefly. Then, I removed and reinstalled the original
fuse and got another burst of life. The fuse was intermittent for a day
before finally going open.

The Panasonic factory fuse was an ABC 125/250V 18A ceramic, but I can
only
find 15A or 20A versions in hardware or electronics stores. Even online,
18A fuses are elusive. Maximum current in this oven is stated as 12.7A
at
1,460 watts. So far the 15A fuse I replaced it with has held up after a
two
days.

Does anyone know why Panasonic uses a rare 18A fuse (vs. 15A or 20A) and
how long a 15A fuse should last?

Jack

Hi Jack...

Here's a couple...

http://www.circuitprotection.ca/MFsearch.php

Take care.

Ken

Jack wrote:
My 2 y/o Panasonic NN-T664 microwave (1300W inverter design) blew a fuse,
apparently due to the fuse simply wearing out. All else seems normal,
including door switches.

The first symptom was loss of display, but unplugging/re-plugging the power
cord restored that briefly. Then, I removed and reinstalled the original
fuse and got another burst of life. The fuse was intermittent for a day
before finally going open.

The Panasonic factory fuse was an ABC 125/250V 18A ceramic, but I can only
find 15A or 20A versions in hardware or electronics stores. Even online,
18A fuses are elusive. Maximum current in this oven is stated as 12.7A at
1,460 watts. So far the 15A fuse I replaced it with has held up after a two
days.

Does anyone know why Panasonic uses a rare 18A fuse (vs. 15A or 20A) and
how long a 15A fuse should last?

Jack



If it were my own oven, I'd try the 15A first and if that blows use a
20A. If a short occurs it'll blow that just as fast as the 18A. If this
is for a customer though I would not go over 18A just because of
liability issues.

On Friday, May 26, 2006 9:37:13 PM UTC-4, James Sweet wrote:
If it were my own oven, I'd try the 15A first and if that blows use a
20A. If a short occurs it'll blow that just as fast as the 18A. If this
is for a customer though I would not go over 18A just because of
liability issues.

Yah right!

I had this microwave repaired under warranty by a tech while I was out of town (my wife needed the microwave. The tech replaced the fuse by a 20A. It held for what.. 6 years? Now I need a new fuse. I won't bother and put a 20A.