Model CBC-00SA4 - voltage surge burnt two of the circuit traces which
I repaired. A component that looks like a capacitor blew. PCB part ID
is "ZNR1". Is this a surge protector? And if so, do I have to replace
with exactly the same part? Could I use similiar compenent from
another electronic device? Hate to trash for this one component.
Thanks as aways group.

I should have added that the component is radial lead, with blue
plastic coating.

And.............the component is connected/tied across the hot and
neutral of the main 125V supply.

On Thu, 29 Jan 2009 13:06:16 -0800 (PST), put finger
to keyboard and composed:

And.............the component is connected/tied across the hot and
neutral of the main 125V supply.

ZNR usually denotes a Metal Oxide Varistor (MOV). Its diameter is an
indicator of its energy rating (Joules). IIRC, a 240VAC system usually
has a 275V MOV. Your mains supply might use a 150V or 175V device.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

On Fri, 30 Jan 2009 11:09:47 +1100, Franc Zabkar
put finger to keyboard and composed:

On Thu, 29 Jan 2009 13:06:16 -0800 (PST), put finger
to keyboard and composed:

And.............the component is connected/tied across the hot and
neutral of the main 125V supply.

ZNR usually denotes a Metal Oxide Varistor (MOV).

ZNR = zinc-oxide nonlinear resistor
http://industrial.panasonic.com/www-...AWA0000PE1.pdf

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

On Jan 29, 6:12*pm, Franc Zabkar wrote:
On Fri, 30 Jan 2009 11:09:47 +1100, Franc Zabkar
put finger to keyboard and composed:

On Thu, 29 Jan 2009 13:06:16 -0800 (PST), put finger
to keyboard and composed:

And.............the component is connected/tied across the hot and
neutral of the main 125V supply.

ZNR usually denotes a Metal Oxide Varistor (MOV).

ZNR = zinc-oxide nonlinear resistorhttp://industrial.panasonic.com/www-data/pdf/AWA0000/AWA0000PE1.pdf

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

Thanks for the info Franc. What I still don't understand is why it is
configured so that the coffee maker would still work with this
component blown. I guess it did protect the rest of the circuit, even
though two traces were blown off.

On Jan 30, 7:14*am, wrote:


Thanks for the info Franc. What I still don't understand is why it is
configured so that the coffee maker would still work with this
component blown. I guess it did protect the rest of the circuit, even
though two traces were blown off

MOVs (Metal Oxide Varistors - basically a voltage-variable resistor)
are intended to protect against overvoltage. As the voltage across
them exceeds the breakdown voltage rating of the device, it switches
over into conduction, basically close to a short circuit. You will
sometimes see a fuse in series with the power lead - when the MOV
goes into conduction, the fuse will blow, protecting the rest of the
circuitry from the overvoltage. If there's nothing but the MOV across
the mains, as soon as it self-destructs from overcurrent, there's
nothing left to protect the downstream components.

Feel free to correct me if I have any of this wrong. I have been
practicing the software dark arts for the last 20 years - far removed
from my EE days.


Jerry