Hi all
has anyone done any exploratory/repair work on these sort of things? You
know the ones, they operate in the 433MHz band I think, and you set some
DIP switches on both bell push and receiver so that the codes match.

I know they are cheap rubbish, and the attrition rate is high; nevertheless I
am thinking of taking a closer look at one that has stopped working. My first
guess was imply that the press switch had failed; but it's a PCB mounted switch
with an ON resistance of 50Ohms, which seems at least hopefull.

There is some failry shonky soldering, some of which I will probably redo. There
is also a little rust on a 3-wire metal cased part with '433.920' marked on it;
a SAW filter I assume? I guess this may have failed, but the LED on the bell push
doesn't go on when you press the switch, and I think this is independant of the
oscillator/transmitter. Oh, and yes I checked the batteries...

As I say, not a big deal, but I'd be interested if anyone knows of any common
failure modes before I get in too deep...

Thanks (and a ding-dong New Year to you all!)
Jon N

In article ,
jkn wrote:
I know they are cheap rubbish, and the attrition rate is high;
nevertheless I am thinking of taking a closer look at one that has
stopped working. My first guess was imply that the press switch had
failed; but it's a PCB mounted switch with an ON resistance of 50Ohms,
which seems at least hopefull.

If it's what's known as a 'tactile' switch - usually with a square base
and four mounting legs (or may be two) and sealed, they can and do fail.
There are lots of variations, though - but they share one thing. Cheap to
make. You can buy dozens for a quid on Ebay. But perhaps not the exact one
you need.

Do a search on Tactile Switch on Ebay and see if anyone sells one
identical to yours.

--
Is the hardness of the butter proportional to the softness of the bread?*

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
jkn writes:
Hi all
has anyone done any exploratory/repair work on these sort of things? You
know the ones, they operate in the 433MHz band I think, and you set some
DIP switches on both bell push and receiver so that the codes match.

I know they are cheap rubbish, and the attrition rate is high; nevertheless I
am thinking of taking a closer look at one that has stopped working. My first
guess was imply that the press switch had failed; but it's a PCB mounted switch
with an ON resistance of 50Ohms, which seems at least hopefull.

There is some failry shonky soldering, some of which I will probably redo. There
is also a little rust on a 3-wire metal cased part with '433.920' marked on it;
a SAW filter I assume? I guess this may have failed, but the LED on the bell push
doesn't go on when you press the switch, and I think this is independant of the
oscillator/transmitter. Oh, and yes I checked the batteries...

As I say, not a big deal, but I'd be interested if anyone knows of any common
failure modes before I get in too deep...

Check for (and clean) battery contacts - corrosion on the permanently
live parts of outdoor electronics is quite common. Corrosion products
caused by battery leakage can be amazingly good insulators too.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

In article ,
Andrew Gabriel wrote:
In article ,
jkn writes:
Hi all has anyone done any exploratory/repair work on these sort of
things? You know the ones, they operate in the 433MHz band I think,
and you set some DIP switches on both bell push and receiver so that
the codes match.

I know they are cheap rubbish, and the attrition rate is high;
nevertheless I am thinking of taking a closer look at one that has
stopped working. My first guess was imply that the press switch had
failed; but it's a PCB mounted switch with an ON resistance of 50Ohms,
which seems at least hopefull.

There is some failry shonky soldering, some of which I will probably
redo. There is also a little rust on a 3-wire metal cased part with
'433.920' marked on it; a SAW filter I assume? I guess this may have
failed, but the LED on the bell push doesn't go on when you press the
switch, and I think this is independant of the oscillator/transmitter.
Oh, and yes I checked the batteries...

As I say, not a big deal, but I'd be interested if anyone knows of any
common failure modes before I get in too deep...

Check for (and clean) battery contacts - corrosion on the permanently
live parts of outdoor electronics is quite common. Corrosion products
caused by battery leakage can be amazingly good insulators too.

I reckon if the switch is showing an on resistance of 50 ohms, it could be
the problem. Especially if the LED doesn't light. Could be proved by
shorting it out and seeing if the LED comes on.

--
*When a clock is hungry it goes back four seconds*

Dave Plowman London SW
To e-mail, change noise into sound.

On Wed, 31 Dec 2014 17:02:07 +0000 (UTC),
(Andrew Gabriel) wrote:

In article ,
jkn writes:
Hi all
has anyone done any exploratory/repair work on these sort of things? You
know the ones, they operate in the 433MHz band I think, and you set some
DIP switches on both bell push and receiver so that the codes match.

I know they are cheap rubbish, and the attrition rate is high; nevertheless I
am thinking of taking a closer look at one that has stopped working. My first
guess was imply that the press switch had failed; but it's a PCB mounted switch
with an ON resistance of 50Ohms, which seems at least hopefull.

There is some failry shonky soldering, some of which I will probably redo. There
is also a little rust on a 3-wire metal cased part with '433.920' marked on it;
a SAW filter I assume? I guess this may have failed, but the LED on the bell push
doesn't go on when you press the switch, and I think this is independant of the
oscillator/transmitter. Oh, and yes I checked the batteries...

As I say, not a big deal, but I'd be interested if anyone knows of any common
failure modes before I get in too deep...

Check for (and clean) battery contacts - corrosion on the permanently
live parts of outdoor electronics is quite common. Corrosion products
caused by battery leakage can be amazingly good insulators too.

That probably explains why my cheap wireless door chime is still
fully functional even after 5 or more years. The only battery I've had
to replace is the 3 x AA cell battery in the sounder unit I keep in my
upstairs office (about 4 or 5 battery changes in total afaicr).

I'm using the wireless door bell as a repeater to our existing
trembler bell mounted on the front door frame which is currently
powered from a pack of 3 PP3s wired in series. I've wired the wireless
sender to the trembler bell via a 12v zenner and small silicon diode
so that when the outside bell push is operated it also powers the
wireless sender.

The tiny 12v battery in the wireless bell push is only ever used if
its own button is pressed to attract my attention, usually by the XYL
when coming back home with a lot of shopping or, occasionally, to
announce her departure if I'm in the office with the door closed.

Operating the wireless sender's own push button doesn't operate the
front door trembler bell (which is handy for testing the wireless door
bell since I can hear it if I leave the office door open for such
testing).

The wireless bell push is never exposed to any extreme weather
conditions that would normally apply in most installations and this
seems to demonstrate the benefit of avoiding such environmental
stresses.

If the problem turns out to be the push button switch (500 ohms on
resistance?), a better solution might be to purchase an ordinary bell
push as a replacement and wire it across the original switch contacts
and relocate the wireless sender on the inside of the door frame where
it can remain nice and dry.
--
J B Good

The wireless bell push is never exposed to any extreme weather
conditions that would normally apply in most installations and this
seems to demonstrate the benefit of avoiding such .

The "environmental stresses" may not be weather related. Our wireless
chimes need to be reset every few months after use by someone (usually a
white van delivery driver) of the "harder I push the louder it rings"
persuasion. It was more often until I supported the circuit board with
rubber washers so it bends less easily.
--
Robin
reply to address is (meant to be) valid

En el artículo ,
jkn escribió:

I know they are cheap rubbish, and the attrition rate is high; nevertheless I
am thinking of taking a closer look at one that has stopped working.

They can't cope with the UK weather. My solution was to fit the cheapo
wireless bellpush inside, then drill through and put a decent Friedland
one outside wired in parallel with the cheapo. Problem solved, and the
batteries can be checked/changed in the dry and warm.

--
(\_/)
(='.'=)
(")_(")

On Thu, 01 Jan 2015 05:39:50 +0000, Johny B Good
wrote:

On Wed, 31 Dec 2014 17:02:07 +0000 (UTC),
(Andrew Gabriel) wrote:

In article ,
jkn writes:
Hi all
has anyone done any exploratory/repair work on these sort of things? You
know the ones, they operate in the 433MHz band I think, and you set some
DIP switches on both bell push and receiver so that the codes match.

I know they are cheap rubbish, and the attrition rate is high; nevertheless I
am thinking of taking a closer look at one that has stopped working. My first
guess was imply that the press switch had failed; but it's a PCB mounted switch
with an ON resistance of 50Ohms, which seems at least hopefull.

There is some failry shonky soldering, some of which I will probably redo. There
is also a little rust on a 3-wire metal cased part with '433.920' marked on it;
a SAW filter I assume? I guess this may have failed, but the LED on the bell push
doesn't go on when you press the switch, and I think this is independant of the
oscillator/transmitter. Oh, and yes I checked the batteries...

As I say, not a big deal, but I'd be interested if anyone knows of any common
failure modes before I get in too deep...

Check for (and clean) battery contacts - corrosion on the permanently
live parts of outdoor electronics is quite common. Corrosion products
caused by battery leakage can be amazingly good insulators too.

That probably explains why my cheap wireless door chime is still
fully functional even after 5 or more years. The only battery I've had
to replace is the 3 x AA cell battery in the sounder unit I keep in my
upstairs office (about 4 or 5 battery changes in total afaicr).

I'm using the wireless door bell as a repeater to our existing
trembler bell mounted on the front door frame which is currently
powered from a pack of 3 PP3s wired in series. I've wired the wireless
sender to the trembler bell via a 12v zenner and small silicon diode
so that when the outside bell push is operated it also powers the
wireless sender.

The tiny 12v battery in the wireless bell push is only ever used if
its own button is pressed to attract my attention, usually by the XYL
when coming back home with a lot of shopping or, occasionally, to
announce her departure if I'm in the office with the door closed.

Operating the wireless sender's own push button doesn't operate the
front door trembler bell (which is handy for testing the wireless door
bell since I can hear it if I leave the office door open for such
testing).

The wireless bell push is never exposed to any extreme weather
conditions that would normally apply in most installations and this
seems to demonstrate the benefit of avoiding such environmental
stresses.

If the problem turns out to be the push button switch (500 ohms on
resistance?), a better solution might be to purchase an ordinary bell
push as a replacement and wire it across the original switch contacts
and relocate the wireless sender on the inside of the door frame where
it can remain nice and dry.


A nice idea, but that would entail drilling through the wood or UPVC
doorframe, which is what they wanted to avoid when they chose the
wireless option.

--

Graham.

%Profound_observation%

Hi Mike

On Thursday, 1 January 2015 11:41:51 UTC, Mike Tomlinson wrote:
En el artículo ,
jkn escribió:

I know they are cheap rubbish, and the attrition rate is high; nevertheless I
am thinking of taking a closer look at one that has stopped working.

They can't cope with the UK weather. My solution was to fit the cheapo
wireless bellpush inside, then drill through and put a decent Friedland
one outside wired in parallel with the cheapo. Problem solved, and the
batteries can be checked/changed in the dry and warm.

Well, yes, but I was really trying to learn if there was a particular area that
'can't cope with the UK weather'. As others have mentioned it may well be the
pushbutton switch (the spec of similar switches seems to indicate an ON
resistance of 0.1 Ohm, so my measurement of 50 Ohm may well indicate a
a problem there) but I was wondering about specific experience.

Your solution may well be the one I will end up with; I wonder what the
Friedland wired bellpushes use for a switch, and why that copes better. I
appreciate that the fact that they run on 12V or so, and with a larger
current, indicates a different type of switch...

Jon N

En el artículo ,
jkn escribió:

I wonder what the
Friedland wired bellpushes use for a switch

Just bare bent copper contacts, but they've been making them for years
and they're in wide use, and seem to cope ok with our weather. Tried to
google for a pic showing the contacts but couldn't find one.

The little switches in the cheapos are enclosed, which makes them trap
moisture and corrode, presumably.

--
(\_/)
(='.'=)
(")_(")

"Mike Tomlinson" wrote in message ...

En el artículo ,
jkn escribió:

I wonder what the
Friedland wired bellpushes use for a switch

Just bare bent copper contacts, but they've been making them for years
and they're in wide use, and seem to cope ok with our weather. Tried to
google for a pic showing the contacts but couldn't find one.

The little switches in the cheapos are enclosed, which makes them trap
moisture and corrode, presumably.

I'm surprised that they are just copper - I'd expect them to be a bronze or
brass to give them resilience and springyness.

Andrew

Hi Mike

On Saturday, 3 January 2015 02:39:29 UTC, Mike Tomlinson wrote:
En el artículo ,
jkn escribió:

I wonder what the
Friedland wired bellpushes use for a switch

Just bare bent copper contacts, but they've been making them for years
and they're in wide use, and seem to cope ok with our weather. Tried to
google for a pic showing the contacts but couldn't find one.


Interesting ... like Andrew Mawson I'd expect them to be something like
phosphor-bronze or similar, but whatever... I will probably pick one up to
take a look

The little switches in the cheapos are enclosed, which makes them trap
moisture and corrode, presumably.

Yes, that's a good point, thanks.

J^n

In article ,
Graham. wrote:
A nice idea, but that would entail drilling through the wood or UPVC
doorframe, which is what they wanted to avoid when they chose the
wireless option.

Most choose the wireless option because it is easy. Then moan on and on
about false rings, not being able to hear it, poor reliability etc.

Put my transformer fed bells in when I re-wired this house 40 years ago.
Still working just fine.

--
*Why don't sheep shrink when it rains?

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
Dave Plowman (News) wrote:
In article ,
Graham. wrote:
A nice idea, but that would entail drilling through the wood or UPVC
doorframe, which is what they wanted to avoid when they chose the
wireless option.

Most choose the wireless option because it is easy. Then moan on and on
about false rings, not being able to hear it, poor reliability etc.

Put my transformer fed bells in when I re-wired this house 40 years ago.
Still working just fine.

with a wireless one you can take a receiver into the garden and still hear
if there's someone at the door.

--
From KT24

Using a RISC OS computer running v5.18

In article ,
charles wrote:
Put my transformer fed bells in when I re-wired this house 40 years
ago. Still working just fine.

with a wireless one you can take a receiver into the garden and still
hear if there's someone at the door.

And then forget you've done it. ;-)

--
*Two many clicks spoil the browse *

Dave Plowman London SW
To e-mail, change noise into sound.

with a wireless one you can take a receiver into the garden and still
hear if there's someone at the door.

And nextdoor-but-one when feeding their cat while they're away -
confuses delivery drivers no end which I consider a "good thing"
--
Robin
reply to address is (meant to be) valid

On Fri, 02 Jan 2015 22:21:38 +0000, Graham. wrote:

On Thu, 01 Jan 2015 05:39:50 +0000, Johny B Good
wrote:

On Wed, 31 Dec 2014 17:02:07 +0000 (UTC),
(Andrew Gabriel) wrote:

In article ,
jkn writes:
Hi all
has anyone done any exploratory/repair work on these sort of things? You
know the ones, they operate in the 433MHz band I think, and you set some
DIP switches on both bell push and receiver so that the codes match.

I know they are cheap rubbish, and the attrition rate is high; nevertheless I
am thinking of taking a closer look at one that has stopped working. My first
guess was imply that the press switch had failed; but it's a PCB mounted switch
with an ON resistance of 50Ohms, which seems at least hopefull.

There is some failry shonky soldering, some of which I will probably redo. There
is also a little rust on a 3-wire metal cased part with '433.920' marked on it;
a SAW filter I assume? I guess this may have failed, but the LED on the bell push
doesn't go on when you press the switch, and I think this is independant of the
oscillator/transmitter. Oh, and yes I checked the batteries...

As I say, not a big deal, but I'd be interested if anyone knows of any common
failure modes before I get in too deep...

Check for (and clean) battery contacts - corrosion on the permanently
live parts of outdoor electronics is quite common. Corrosion products
caused by battery leakage can be amazingly good insulators too.

That probably explains why my cheap wireless door chime is still
fully functional even after 5 or more years. The only battery I've had
to replace is the 3 x AA cell battery in the sounder unit I keep in my
upstairs office (about 4 or 5 battery changes in total afaicr).

I'm using the wireless door bell as a repeater to our existing
trembler bell mounted on the front door frame which is currently
powered from a pack of 3 PP3s wired in series. I've wired the wireless
sender to the trembler bell via a 12v zenner and small silicon diode
so that when the outside bell push is operated it also powers the
wireless sender.

The tiny 12v battery in the wireless bell push is only ever used if
its own button is pressed to attract my attention, usually by the XYL
when coming back home with a lot of shopping or, occasionally, to
announce her departure if I'm in the office with the door closed.

Operating the wireless sender's own push button doesn't operate the
front door trembler bell (which is handy for testing the wireless door
bell since I can hear it if I leave the office door open for such
testing).

The wireless bell push is never exposed to any extreme weather
conditions that would normally apply in most installations and this
seems to demonstrate the benefit of avoiding such environmental
stresses.

If the problem turns out to be the push button switch (500 ohms on
resistance?), a better solution might be to purchase an ordinary bell
push as a replacement and wire it across the original switch contacts
and relocate the wireless sender on the inside of the door frame where
it can remain nice and dry.


A nice idea, but that would entail drilling through the wood or UPVC
doorframe, which is what they wanted to avoid when they chose the
wireless option.

Fair enough but the OP was considering a repair of the door bell
sender so might view this as a possible solution. After all, it's only
a matter of a metre or two of wiring, the sender still saves on
running a wire to a remote bell.
--
J B Good

On Sat, 3 Jan 2015 09:08:24 -0000, "Andrew Mawson"
wrote:

"Mike Tomlinson" wrote in message ...

En el artículo ,
jkn escribió:

I wonder what the
Friedland wired bellpushes use for a switch

Just bare bent copper contacts, but they've been making them for years
and they're in wide use, and seem to cope ok with our weather. Tried to
google for a pic showing the contacts but couldn't find one.

The little switches in the cheapos are enclosed, which makes them trap
moisture and corrode, presumably.

I'm surprised that they are just copper - I'd expect them to be a bronze or
brass to give them resilience and springyness.


The last time I looked at such a door bell switch, it was just a
couple of brass strips pushed together by the button press. They had a
decent airgap considering the low voltage and made a sliding/rubbing
contact which bodes well for maintained low on resistance (or even the
option for the operator to find 'The Sweet Spot' when age finally
takes its toll on the switch - crude but effective).
--
J B Good

On Tuesday, January 6, 2015 10:51:06 AM UTC, Johny B Good wrote:
On Sat, 3 Jan 2015 09:08:24 -0000, "Andrew Mawson"
wrote:

"Mike Tomlinson" wrote in message ....

En el artículo ,
jkn escribió:

I wonder what the
Friedland wired bellpushes use for a switch

Just bare bent copper contacts, but they've been making them for years
and they're in wide use, and seem to cope ok with our weather. Tried to
google for a pic showing the contacts but couldn't find one.

The little switches in the cheapos are enclosed, which makes them trap
moisture and corrode, presumably.

I'm surprised that they are just copper - I'd expect them to be a bronze or
brass to give them resilience and springyness.


The last time I looked at such a door bell switch, it was just a
couple of brass strips pushed together by the button press. They had a
decent airgap considering the low voltage and made a sliding/rubbing
contact which bodes well for maintained low on resistance (or even the
option for the operator to find 'The Sweet Spot' when age finally
takes its toll on the switch - crude but effective).
--
J B Good

I'm a +1 to removing the sender from outside. My experience was that it was the contact between the button cells that was the problem due to the weather. I was fortunate in that I had cable already in place to put a decent push button switch, and put the original sender up in the attic where it has a wider range of transmission as well.

Rob