dead microwave

[james]

Frigidaire, Professional Series PLMV169DCD

When plugged in, no clock is displayed. Nothing. No response to any buttons.
No lights, no fan, no sound.
It failed gradually. Starting from a few buttons that didn't work, then
this.

It is a combo microwave/range hood. I opened up the panel/keyboard. There's
a layer of grease on the circult board, and some grease droplets dangling on
wires and connectors. Some greenish(!) grease drips out of connectors. Could
the grease cause the connectors to fail?

I found on the internet a parts and schematic PDF for this model.
Unfortunately, the schematic shows everything (relays, transformers, lights,
fuses, magnetron, motors) but the controller board. Yet the controller board
is where I want to start debugging since it houses the LCD display and hooks
up to the keypad. Does anyone know where to get the controller board's
schematic?

BTW, there's a note inside saying "this device should not be serviced by a
do-it-yourself repair person". I could understand if it says "this device
should be serviced only by a qualified person". But why get personal?

 

[William Sommerwerck]

BTW, there's a note inside saying "this device should not be
serviced by a do-it-yourself repair person". I could understand
if it says "this device should be serviced only by a qualified
person". But why get personal?

"I don't get no respect!"

Why not start by simply cleaning up everything? The only thing you might
have to worry about is electrostatic discharge damaging the controller or
other electronic components.

 

[Arfa Daily]

<hrhofmann@att.net> wrote in message
news:3c5b4d13-bdf2-45ef-99db-1f38bd82a785@l20g2000yqm.googlegroups.com...

On Oct 15, 1:37 pm, "William Sommerwerck" <grizzledgee...@comcast.net
wrote:
BTW, there's a note inside saying "this device should not be
serviced by a do-it-yourself repair person". I could understand
if it says "this device should be serviced only by a qualified
person". But why get personal?

"I don't get no respect!"

Why not start by simply cleaning up everything? The only thing you might
have to worry about is electrostatic discharge damaging the controller or
other electronic components.

I would suggest some naptha and a soft brush to dissolve the grease
and clean the board. Do NOT use soap and /or water!!!! After
everything looks clean and nice, let it sit overnoght before you plug
it back in. That gives time for things to dry out reasonably well.

Surely, the most fundamental first move is to take a meter to the power
supply, and see if there is at least some supply to the system control micro
etc ? The fact that it's covered in grease may well be neither here nor
there as far as the fault goes. Oils and greases are not known for being
particularly conductive or corrosive. Dead is a positive problem, and one to
which basic faultfinding techniques should be first applied, before going
off on an 'if-then-maybe' exercise ...

Arfa

 

[Meat Plow]

On Fri, 15 Oct 2010 10:56:04 -0700, james wrote:

Frigidaire, Professional Series PLMV169DCD

When plugged in, no clock is displayed. Nothing. No response to any
buttons. No lights, no fan, no sound.
It failed gradually. Starting from a few buttons that didn't work, then
this.

Uh Huh.

It is a combo microwave/range hood. I opened up the panel/keyboard.
There's a layer of grease on the circult board, and some grease droplets
dangling on wires and connectors. Some greenish(!) grease drips out of
connectors. Could the grease cause the connectors to fail?

Yep

I found on the internet a parts and schematic PDF for this model.
Unfortunately, the schematic shows everything (relays, transformers,
lights, fuses, magnetron, motors) but the controller board. Yet the
controller board is where I want to start debugging since it houses the
LCD display and hooks up to the keypad. Does anyone know where to get
the controller board's schematic?

Controllers are usually replaced not serviced.

BTW, there's a note inside saying "this device should not be serviced by
a do-it-yourself repair person". I could understand if it says "this
device should be serviced only by a qualified person". But why get
personal?

Because your health depends on you knowing what you are doing. What price
are you willing to see yourself and others possibly pay for a more
friendly message?


--
Live Fast, Die Young and Leave a Pretty Corpse

 

[hrhofmann@att.net]

On Oct 15, 1:37 pm, "William Sommerwerck" <grizzledgee...@comcast.net>
wrote:

BTW, there's a note inside saying "this device should not be
serviced by a do-it-yourself repair person". I could understand
if it says "this device should be serviced only by a qualified
person". But why get personal?

"I don't get no respect!"

Why not start by simply cleaning up everything? The only thing you might
have to worry about is electrostatic discharge damaging the controller or
other electronic components.

I would suggest some naptha and a soft brush to dissolve the grease
and clean the board. Do NOT use soap and /or water!!!! After
everything looks clean and nice, let it sit overnoght before you plug
it back in. That gives time for things to dry out reasonably well.

 

[William Sommerwerck]

Surely, the most fundamental first move is to take a meter to the power
supply, and see if there is at least some supply to the system control
micro etc ? The fact that it's covered in grease may well be neither here
nor there as far as the fault goes. Oils and greases are not known for
being particularly conductive or corrosive. Dead is a positive problem,
and one to which basic faultfinding techniques should be first applied,
before going off on an 'if-then-maybe' exercise ...

I'd normally agree, but the fact the unit /slowly/ declined suggests that
something other than a voltage loss is going on.

Of course, it takes just a few seconds to check the voltages. Couldn't hurt.

 

[Cydrome Leader]

james <nospam@nospam.com> wrote:

Frigidaire, Professional Series PLMV169DCD

When plugged in, no clock is displayed. Nothing. No response to any buttons.
No lights, no fan, no sound.
It failed gradually. Starting from a few buttons that didn't work, then
this.

It is a combo microwave/range hood. I opened up the panel/keyboard. There's
a layer of grease on the circult board, and some grease droplets dangling on
wires and connectors. Some greenish(!) grease drips out of connectors. Could
the grease cause the connectors to fail?

I found on the internet a parts and schematic PDF for this model.
Unfortunately, the schematic shows everything (relays, transformers, lights,
fuses, magnetron, motors) but the controller board. Yet the controller board
is where I want to start debugging since it houses the LCD display and hooks
up to the keypad. Does anyone know where to get the controller board's
schematic?

BTW, there's a note inside saying "this device should not be serviced by a
do-it-yourself repair person". I could understand if it says "this device
should be serviced only by a qualified person". But why get personal?

That is an odd warning. Microwaves should just state "you will die if you
open this, even if it's unplugged.

 

[Arfa Daily]

"William Sommerwerck" <grizzledgeezer@comcast.net> wrote in message
news:i9aetj$8ke$1@news.eternal-september.org...

Surely, the most fundamental first move is to take a meter to the power
supply, and see if there is at least some supply to the system control
micro etc ? The fact that it's covered in grease may well be neither here
nor there as far as the fault goes. Oils and greases are not known for
being particularly conductive or corrosive. Dead is a positive problem,
and one to which basic faultfinding techniques should be first applied,
before going off on an 'if-then-maybe' exercise ...

I'd normally agree, but the fact the unit /slowly/ declined suggests that
something other than a voltage loss is going on.

Well, not really. Analogue power supplies, such as the ones in microwave
ovens usually are, will die gracefully as a result of bad electrolytics
getting worse.

Arfa

 

[William Sommerwerck]

I'd normally agree, but the fact the unit /slowly/ declined suggests
that something other than a voltage loss is going on.

Well, not really. Analogue power supplies, such as the ones in
microwave ovens usually are, will die gracefully as a result of bad
electrolytics getting worse.

I've never seen this, but I sure don't know everything. Anyhow, what about
the fact that some buttons "failed" before others? (That's a rhetorical
question.)

 

[Arfa Daily]

"William Sommerwerck" <grizzledgeezer@comcast.net> wrote in message
news:i9c0fe$h4n$1@news.eternal-september.org...

I'd normally agree, but the fact the unit /slowly/ declined suggests
that something other than a voltage loss is going on.

Well, not really. Analogue power supplies, such as the ones in
microwave ovens usually are, will die gracefully as a result of bad
electrolytics getting worse.

I've never seen this, but I sure don't know everything. Anyhow, what about
the fact that some buttons "failed" before others? (That's a rhetorical
question.)

Understood a rhet question, but I guess it still might need an answer for
others following the thread.

If a supply that's feeding a logic device such as a microcontroller becomes
'dirty' - that's either with excessive ripple from an analogue supply, or
hash from a switch mode supply, and both cases potentially caused by a
failing filter cap, - then operation of the micro can become 'flaky'. This
can take the form of odd / unreliable behaviour, incorrect reset at power
up, incorrect operation of any connected displays, and wrong operation of
connected peripherals such as keypads, fault sensors etc. This is
particularly true of devices which use A-D converter inputs with a ladder of
resistors connected between buttons, to sense which button has been pressed,
although it can also occur with matrix driven / sensed keypads.

Arfa

 

[Arfa Daily]

"Meat Plow" <mhywatt@yahoo.com> wrote in message
newsan.2010.10.16.12.34.20@lmao.lol.lol...

On Sat, 16 Oct 2010 03:57:47 -0700, William Sommerwerck wrote:

I'd normally agree, but the fact the unit /slowly/ declined suggests
that something other than a voltage loss is going on.

Well, not really. Analogue power supplies, such as the ones in
microwave ovens usually are, will die gracefully as a result of bad
electrolytics getting worse.

I've never seen this, but I sure don't know everything. Anyhow, what
about the fact that some buttons "failed" before others? (That's a
rhetorical question.)

The microwave as I understood was above a stove and was probably cleaned
frequently because of its location. I've seen many control panels
permanently damaged by cleaning fluids on not only microwaves but also
other home appliances and electronics. This fact can certainly account
for button failure.



--

Agreed. I was just thinking of a scenario that would account for both
progressive failure of buttons, and then ultimately (apparent) total failure
of the unit to operate at all.

Arfa

 

[Meat Plow]

On Sat, 16 Oct 2010 03:57:47 -0700, William Sommerwerck wrote:

I'd normally agree, but the fact the unit /slowly/ declined suggests
that something other than a voltage loss is going on.

Well, not really. Analogue power supplies, such as the ones in
microwave ovens usually are, will die gracefully as a result of bad
electrolytics getting worse.

I've never seen this, but I sure don't know everything. Anyhow, what
about the fact that some buttons "failed" before others? (That's a
rhetorical question.)

The microwave as I understood was above a stove and was probably cleaned
frequently because of its location. I've seen many control panels
permanently damaged by cleaning fluids on not only microwaves but also
other home appliances and electronics. This fact can certainly account
for button failure.



--
Live Fast, Die Young and Leave a Pretty Corpse

 

[Meat Plow]

On Sat, 16 Oct 2010 14:41:02 +0100, Arfa Daily wrote:

"Meat Plow" <mhywatt@yahoo.com> wrote in message
newsan.2010.10.16.12.34.20@lmao.lol.lol...
On Sat, 16 Oct 2010 03:57:47 -0700, William Sommerwerck wrote:

I'd normally agree, but the fact the unit /slowly/ declined suggests
that something other than a voltage loss is going on.

Well, not really. Analogue power supplies, such as the ones in
microwave ovens usually are, will die gracefully as a result of bad
electrolytics getting worse.

I've never seen this, but I sure don't know everything. Anyhow, what
about the fact that some buttons "failed" before others? (That's a
rhetorical question.)

The microwave as I understood was above a stove and was probably
cleaned frequently because of its location. I've seen many control
panels permanently damaged by cleaning fluids on not only microwaves
but also other home appliances and electronics. This fact can certainly
account for button failure.



--

Agreed. I was just thinking of a scenario that would account for both
progressive failure of buttons, and then ultimately (apparent) total
failure of the unit to operate at all.

Arfa

Total failure as in front panel function could easily result from
cleaning fluids, corrosive cooking vapors, condensation etc..
I don't recall if the OP mentioned the interior light working when the
door was opened.



--
Live Fast, Die Young and Leave a Pretty Corpse

 

[Jim Yanik]

"Arfa Daily" <arfa.daily@ntlworld.com> wrote in
newsXhuo.1843$jH7.1212@newsfe29.ams2:

"Meat Plow" <mhywatt@yahoo.com> wrote in message
newsan.2010.10.16.12.34.20@lmao.lol.lol...
On Sat, 16 Oct 2010 03:57:47 -0700, William Sommerwerck wrote:

I'd normally agree, but the fact the unit /slowly/ declined
suggests that something other than a voltage loss is going on.

Well, not really. Analogue power supplies, such as the ones in
microwave ovens usually are, will die gracefully as a result of bad
electrolytics getting worse.

I've never seen this, but I sure don't know everything. Anyhow, what
about the fact that some buttons "failed" before others? (That's a
rhetorical question.)

The microwave as I understood was above a stove and was probably
cleaned frequently because of its location. I've seen many control
panels permanently damaged by cleaning fluids on not only microwaves
but also other home appliances and electronics. This fact can
certainly account for button failure.



--

Agreed. I was just thinking of a scenario that would account for both
progressive failure of buttons, and then ultimately (apparent) total
failure of the unit to operate at all.

Arfa

grease infiltration into the keypad could be the first problem,and then
grease making a conductive path and the HV shorting out and blowing the
line fuse.

I finally "retired" my 30 year old,$350USD Sharp MW,replaced it with a $99
GE from Wal-Mart;1.8Cu.Ft.,1100W.
Had to return the first one,the turntable didn't turn....

then I realized how much the power had dropped on the older 700W Sharp. ;-)


I don't expect the GE to last half as long as the Sharp did.

--
Jim Yanik
jyanik
at
localnet
dot com

 

[hrhofmann@att.net]

On Oct 16, 9:34 am, Meat Plow <mhyw...@yahoo.com> wrote:

On Sat, 16 Oct 2010 14:41:02 +0100, Arfa Daily wrote:
"Meat Plow" <mhyw...@yahoo.com> wrote in message
newsan.2010.10.16.12.34.20@lmao.lol.lol...
On Sat, 16 Oct 2010 03:57:47 -0700, William Sommerwerck wrote:

I'd normally agree, but the fact the unit /slowly/ declined suggests
that something other than a voltage loss is going on.

Well, not really. Analogue power supplies, such as the ones in
microwave ovens usually are, will die gracefully as a result of bad
electrolytics getting worse.

I've never seen this, but I sure don't know everything. Anyhow, what
about the fact that some buttons "failed" before others? (That's a
rhetorical question.)

The microwave as I understood was above a stove and was probably
cleaned frequently because of its location. I've seen many control
panels permanently damaged by cleaning fluids on not only microwaves
but also other home appliances and electronics. This fact can certainly
account for button failure.

--

Agreed. I was just thinking of a scenario that would account for both
progressive failure of buttons, and then ultimately (apparent) total
failure of the unit to operate at all.

Arfa

Total failure as in front panel function could easily result from
cleaning fluids, corrosive cooking vapors, condensation etc..
I don't recall if the OP mentioned the interior light working when the
door was opened.

--
Live Fast, Die Young and Leave a Pretty Corpse- Hide quoted text -

- Show quoted text -

Excellent point about the interior door/light, that is usually a
combination of microswitches and a relay contact from the controller
so the light goes on if the door is opened or if it is cooking.

 

[Klaatu]

"Jim Yanik" <jyanik@abuse.gov> wrote in message
news:Xns9E138A1338FF3jyaniklocalnetcom@216.168.3.44...

"Arfa Daily" <arfa.daily@ntlworld.com> wrote in
newsXhuo.1843$jH7.1212@newsfe29.ams2:



"Meat Plow" <mhywatt@yahoo.com> wrote in message
newsan.2010.10.16.12.34.20@lmao.lol.lol...
On Sat, 16 Oct 2010 03:57:47 -0700, William Sommerwerck wrote:

I'd normally agree, but the fact the unit /slowly/ declined
suggests that something other than a voltage loss is going on.

Well, not really. Analogue power supplies, such as the ones in
microwave ovens usually are, will die gracefully as a result of bad
electrolytics getting worse.

I've never seen this, but I sure don't know everything. Anyhow, what
about the fact that some buttons "failed" before others? (That's a
rhetorical question.)

The microwave as I understood was above a stove and was probably
cleaned frequently because of its location. I've seen many control
panels permanently damaged by cleaning fluids on not only microwaves
but also other home appliances and electronics. This fact can
certainly account for button failure.



--

Agreed. I was just thinking of a scenario that would account for both
progressive failure of buttons, and then ultimately (apparent) total
failure of the unit to operate at all.

Arfa



grease infiltration into the keypad could be the first problem,and then
grease making a conductive path and the HV shorting out and blowing the
line fuse.

I finally "retired" my 30 year old,$350USD Sharp MW,replaced it with a $99
GE from Wal-Mart;1.8Cu.Ft.,1100W.
Had to return the first one,the turntable didn't turn....

then I realized how much the power had dropped on the older 700W Sharp.
;-)


I don't expect the GE to last half as long as the Sharp did.

--
Jim Yanik
jyanik
at
localnet
dot com

If it has GE on the front, you'll be lucky to make it past the first year.
ESPECIALLY if you bought it at Wal-Mart.

 

[William Sommerwerck]

If it has GE on the front, you'll be lucky to make it past the first year.

My GE over-the-cooktop microwave is 11 years old, gets near-daily use, and
is a-working still.

 

[Jeffrey Angus]

On 10/18/2010 6:18 AM, William Sommerwerck wrote:

If it has GE on the front, you'll be lucky to make it past the first year.

My GE over-the-cooktop microwave is 11 years old, gets near-daily use, and
is a-working still.

That's because it IS 11 years old.
The reference was for the new ones being sold at Wal=Mart.

Jeff

 

[William Sommerwerck]

If it has GE on the front, you'll be lucky to make it past
the first year.

My GE over-the-cooktop microwave is 11 years old,
gets near-daily use, and is a-working still.

That's because it IS 11 years old.
The reference was for the new ones being sold at Wal-Mart.

I still have one of the last made-in-the US Littons, which I can pull out if
the GE fails.

Does anyone make a really good, reliable microwave?

PS: There's a classic MAD spoof showing an Appalachian family (is that
sufficiently PC) around their washing machine, which has been converted for
alcohol production: "Our Mayjag is 18 years old, and it's a-working still!"

 

[Jeff Liebermann]

On Sat, 16 Oct 2010 14:34:28 +0000 (UTC), Meat Plow
<mhywatt@yahoo.com> wrote:

Total failure as in front panel function could easily result from
cleaning fluids, corrosive cooking vapors, condensation etc..
I don't recall if the OP mentioned the interior light working when the
door was opened.

I was once asked to look at a heavily used microwave oven at a local
residential facility. The description was similar, but the problem
was obvious on first inspection. Long finger nails punching through
the elastometric contact keyboard. Once the protective membrane on
the front panel is punctured, all manner of liquids and gasses can
cause damage. I've seen this problem other times, where the customer
doesn't want to admit that they damaged the front panel, or somehow
considers such damage as normal. It also applies to TV/hi-fi remote
controls, printer control panels, calculators, where easily damaged
flexible membranes are used in place of hard plastic buttons.

While grease is usually non-conductive, having any grease in the
various connectors will produce lousy connections. I suspect a good
cleaning, and a low grease diet, might restore the oven to normal
operation. The green crud (copper sulfate) does not necessarily
signal the demise of the wiring, unless it's extensive. I would not
replace any electronics until the keyboard and controller cards are
baptized in solvent. It would also be interesting to determine how
the grease entered the area. Probably a mechanically mis-aligned
exhaust duct.

Opinions:
<http://www.epinions.com/reviews/Frigidaire_PLMV169DC_Stainless_Steel_Microwave_Oven>
This one is interesting:
<http://www.epinions.com/review/Frigidaire_PLMV169DC_Stainless_Steel_Microwave_Oven/content_392811679364>
The Bottom Line: Despite the top-flight brand name, attractive
styling, and high price tag, this microwave is unreliable and
extremely difficult to clean.

Drivel: US DoE can't figure out how to measure microwave oven power
output.
<http://www.federalregister.gov/articles/2010/07/22/2010-17773/energy-conservation-program-for-consumer-products-test-procedure-for-microwave-ovens-repeal-of>
Sigh.


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558