"RJH" wrote in message
...
I've taken the cover off, and noticed the battery seems to be
leaking slightly:

https://flic.kr/p/EdXFsh

There's a white furry deposit around what I assume to be the
battery - the blue thing centre top. The underside of the circuit
board looks fine.

Is a replacement straightforward? I can solder after a fashion.

A recommended source for a replacement? A google search throws up
quite a few options.

Would I be best not using it until the replacement's in?


Phil is right but I would wait until you have extracted it before
buying a replacement as it could be Ni-Cad or Ni-MH depending on the
age of the tuner, and they require slightly different charging
regimes. Equally it could be 3V, 3.6V or 4.8V although I would admit
that the size suggests the latter.

You can removed the battery and clean the PCB and then continue to use
the tuner - it will just not remember memory settings when powered
down. Having said that it takes little power so you could just leave
it switched on. Do however make sure that the battery wires are
insulated after you remove the battery but before use. Also take care
unsoldering - remove the negative (black) first so that if you
accidently short the positive to chassis northing will happen: Ni-MH
batteries (if that is what it is) can supply quite a bit of current
for a short time.

Have a look at
http://cpc.farnell.com/webapp/wcs/st...1541,110151587
who stock just about every type you might need. Maplins also stock
some but only a limited range and possibly a bit more expensive.


--
Woody

harrogate3 at ntlworld dot com

On 19/02/2016 08:45, Woody wrote:
"RJH" wrote in message
...
I've taken the cover off, and noticed the battery seems to be
leaking slightly:

https://flic.kr/p/EdXFsh

There's a white furry deposit around what I assume to be the
battery - the blue thing centre top. The underside of the circuit
board looks fine.

Is a replacement straightforward? I can solder after a fashion.

A recommended source for a replacement? A google search throws up
quite a few options.

Would I be best not using it until the replacement's in?


Phil is right but I would wait until you have extracted it before
buying a replacement as it could be Ni-Cad or Ni-MH depending on the
age of the tuner, and they require slightly different charging
regimes. Equally it could be 3V, 3.6V or 4.8V although I would admit
that the size suggests the latter.


OK, will do, thanks (and Phil).

You can removed the battery and clean the PCB and then continue to use
the tuner - it will just not remember memory settings when powered
down. Having said that it takes little power so you could just leave
it switched on. Do however make sure that the battery wires are
insulated after you remove the battery but before use. Also take care
unsoldering - remove the negative (black) first so that if you
accidently short the positive to chassis northing will happen: Ni-MH
batteries (if that is what it is) can supply quite a bit of current
for a short time.

Have a look at
http://cpc.farnell.com/webapp/wcs/st...1541,110151587
who stock just about every type you might need. Maplins also stock
some but only a limited range and possibly a bit more expensive.


Great, thanks.

However, another problem. The tuner is new to me, and I'm told it was
working quite recently. However, I can't get any sound out of it. The
signal bar is showing 7/10 and the stereo light is on, so I'm guessing
that's enough?

Also, the memory store (hold Tune down and choose a preset) isn't
working. I'd think this might be down to the battery, although the
previous owner's presets can be recalled quite merrily - most with a
5-6/10 signal.

Might this be to do with the strength of the signal - I'm just using a
table top FM aerial. Or something more serious, do you think?


--
Cheers, Rob

"RJH" wrote in message
...
On 19/02/2016 08:45, Woody wrote:
"RJH" wrote in message
...
I've taken the cover off, and noticed the battery seems to be
leaking slightly:

https://flic.kr/p/EdXFsh

There's a white furry deposit around what I assume to be the
battery - the blue thing centre top. The underside of the circuit
board looks fine.

Is a replacement straightforward? I can solder after a fashion.

A recommended source for a replacement? A google search throws up
quite a few options.

Would I be best not using it until the replacement's in?


Phil is right but I would wait until you have extracted it before
buying a replacement as it could be Ni-Cad or Ni-MH depending on
the
age of the tuner, and they require slightly different charging
regimes. Equally it could be 3V, 3.6V or 4.8V although I would
admit
that the size suggests the latter.


OK, will do, thanks (and Phil).

You can removed the battery and clean the PCB and then continue to
use
the tuner - it will just not remember memory settings when powered
down. Having said that it takes little power so you could just
leave
it switched on. Do however make sure that the battery wires are
insulated after you remove the battery but before use. Also take
care
unsoldering - remove the negative (black) first so that if you
accidently short the positive to chassis northing will happen:
Ni-MH
batteries (if that is what it is) can supply quite a bit of current
for a short time.

Have a look at
http://cpc.farnell.com/webapp/wcs/st...1541,110151587
who stock just about every type you might need. Maplins also stock
some but only a limited range and possibly a bit more expensive.


Great, thanks.

However, another problem. The tuner is new to me, and I'm told it
was working quite recently. However, I can't get any sound out of
it. The signal bar is showing 7/10 and the stereo light is on, so
I'm guessing that's enough?

Also, the memory store (hold Tune down and choose a preset) isn't
working. I'd think this might be down to the battery, although the
previous owner's presets can be recalled quite merrily - most with a
5-6/10 signal.

Might this be to do with the strength of the signal - I'm just using
a table top FM aerial. Or something more serious, do you think?



Change the battery first. If it is low and cannot charge it may be
pulling down the supply rail which is preventing other things from
working properly. The battery is 4V.

The audio output has a mute circuit on it for start up to prevent
noises - it could have something to do with lack of sound. If the
aerial is connected, you are showing a signal, and the stereo beacon
is lit it shows the tuner has enough signal. This may also be an audio
stage electrolytic capacitor problem - see the next paragraph.

I suggest you look at this video
https://www.youtube.com/watch?v=RXVuPcNLyWw
and read the first comment beneath. The 'electrolytics' are the
smoothing capacitors in the power supply and they dry out with age.
They are 1000uF (microfarad) each probably 35V or 45V or 63V. Such
components are easy to obtain.

If you go to
http://elektrotanya.com/quad_fm4_sm.pdf/download.html
you can download the manual - which includes the circuit diagram -
free of charge.

If you bought the tuner on eBay as working then I would suggest before
you do anything to it you start a grievance procedure. If you know
what you are doing they are easy enough to fix, but for a tuner of
that age a rather more comprehensive reworking may be needed.


--
Woody

harrogate3 at ntlworld dot com

On 19/02/2016 16:23, Woody wrote:
"RJH" wrote in message
...
On 19/02/2016 08:45, Woody wrote:
"RJH" wrote in message
...
I've taken the cover off, and noticed the battery seems to be
leaking slightly:

https://flic.kr/p/EdXFsh

There's a white furry deposit around what I assume to be the
battery - the blue thing centre top. The underside of the circuit
board looks fine.

Is a replacement straightforward? I can solder after a fashion.

A recommended source for a replacement? A google search throws up
quite a few options.

Would I be best not using it until the replacement's in?


Phil is right but I would wait until you have extracted it before
buying a replacement as it could be Ni-Cad or Ni-MH depending on
the
age of the tuner, and they require slightly different charging
regimes. Equally it could be 3V, 3.6V or 4.8V although I would
admit
that the size suggests the latter.


OK, will do, thanks (and Phil).

You can removed the battery and clean the PCB and then continue to
use
the tuner - it will just not remember memory settings when powered
down. Having said that it takes little power so you could just
leave
it switched on. Do however make sure that the battery wires are
insulated after you remove the battery but before use. Also take
care
unsoldering - remove the negative (black) first so that if you
accidently short the positive to chassis northing will happen:
Ni-MH
batteries (if that is what it is) can supply quite a bit of current
for a short time.

Have a look at
http://cpc.farnell.com/webapp/wcs/st...1541,110151587
who stock just about every type you might need. Maplins also stock
some but only a limited range and possibly a bit more expensive.


Great, thanks.

However, another problem. The tuner is new to me, and I'm told it
was working quite recently. However, I can't get any sound out of
it. The signal bar is showing 7/10 and the stereo light is on, so
I'm guessing that's enough?

Also, the memory store (hold Tune down and choose a preset) isn't
working. I'd think this might be down to the battery, although the
previous owner's presets can be recalled quite merrily - most with a
5-6/10 signal.

Might this be to do with the strength of the signal - I'm just using
a table top FM aerial. Or something more serious, do you think?



Change the battery first. If it is low and cannot charge it may be
pulling down the supply rail which is preventing other things from
working properly. The battery is 4V.

The audio output has a mute circuit on it for start up to prevent
noises - it could have something to do with lack of sound. If the
aerial is connected, you are showing a signal, and the stereo beacon
is lit it shows the tuner has enough signal. This may also be an audio
stage electrolytic capacitor problem - see the next paragraph.

I suggest you look at this video
https://www.youtube.com/watch?v=RXVuPcNLyWw
and read the first comment beneath. The 'electrolytics' are the
smoothing capacitors in the power supply and they dry out with age.
They are 1000uF (microfarad) each probably 35V or 45V or 63V. Such
components are easy to obtain.

If you go to
http://elektrotanya.com/quad_fm4_sm.pdf/download.html
you can download the manual - which includes the circuit diagram -
free of charge.

If you bought the tuner on eBay as working then I would suggest before
you do anything to it you start a grievance procedure. If you know
what you are doing they are easy enough to fix, but for a tuner of
that age a rather more comprehensive reworking may be needed.


Thanks, yes - I've contacted the seller, I'll see what he says.

--
Cheers, Rob

RJH wrote:


Phil is right but I would wait until you have extracted it before
buying a replacement as it could be Ni-Cad or Ni-MH depending on the
age of the tuner, and they require slightly different charging
regimes. Equally it could be 3V, 3.6V or 4.8V although I would admit
that the size suggests the latter.


** AFAIK, Quad FM4s only ever used 4.8V NiCd battery packs with four cells specially made for memory back-up. It was trickle charged at a few mA whenever the tuner was powered up.

I doubt any re-engineering is needed to employ a four cell NiMH pack instead.


..... Phil

No Phil, I was thinking more about dried out electrolytics. It is
possible that such a cap has dried and gone leaky that is causing the
mute circuit to stay active.


--
Woody

harrogate3 at ntlworld dot com


"Phil Allison" wrote in message
...
RJH wrote:


Phil is right but I would wait until you have extracted it before
buying a replacement as it could be Ni-Cad or Ni-MH depending on
the
age of the tuner, and they require slightly different charging
regimes. Equally it could be 3V, 3.6V or 4.8V although I would
admit
that the size suggests the latter.


** AFAIK, Quad FM4s only ever used 4.8V NiCd battery packs with four
cells specially made for memory back-up. It was trickle charged at a
few mA whenever the tuner was powered up.

I doubt any re-engineering is needed to employ a four cell NiMH pack
instead.


.... Phil

On Sat, 20 Feb 2016 04:40:14 -0800, Phil Allison wrote:

RJH wrote:


Phil is right but I would wait until you have extracted it before
buying a replacement as it could be Ni-Cad or Ni-MH depending on the
age of the tuner, and they require slightly different charging
regimes. Equally it could be 3V, 3.6V or 4.8V although I would admit
that the size suggests the latter.


** AFAIK, Quad FM4s only ever used 4.8V NiCd battery packs with four
cells specially made for memory back-up. It was trickle charged at a few
mA whenever the tuner was powered up.

I doubt any re-engineering is needed to employ a four cell NiMH pack
instead.


Agreed, In fact, when I was looking for a replacement 3 cell NiCd for a
Potterton 2000 CH program controller, they'd changed to a larger capacity
NiMH version. Oddly, the tagless drop in batteries used by this
programmer were over twice the price of the solder tagged ones.

Naturally, I bought the cheaper tagged battery and pulled the tags off
and dressed the 'pips' with a fine file to recreate the plug in version
at less than half price for less than ten minutes of D-I-Y activity. :-)

The 4.8 volts seems unusually high for battery backed memory though. The
more usual with static cmos ram being 3.6 volts. CMOS sram is guaranteed
to retain data integrity right down to the 2 volt point - and that
includes the RTCs with their 70 8 bit registers 'going spare' as used by
IBM in their AT PCs first marketed back in August 1984).

--
Johnny B Good

"Johnny B Good" wrote in message
...
On Sat, 20 Feb 2016 04:40:14 -0800, Phil Allison wrote:

RJH wrote:


Phil is right but I would wait until you have extracted it
before
buying a replacement as it could be Ni-Cad or Ni-MH depending on
the
age of the tuner, and they require slightly different charging
regimes. Equally it could be 3V, 3.6V or 4.8V although I would
admit
that the size suggests the latter.


** AFAIK, Quad FM4s only ever used 4.8V NiCd battery packs with
four
cells specially made for memory back-up. It was trickle charged at
a few
mA whenever the tuner was powered up.

I doubt any re-engineering is needed to employ a four cell NiMH
pack
instead.


Agreed, In fact, when I was looking for a replacement 3 cell NiCd
for a
Potterton 2000 CH program controller, they'd changed to a larger
capacity
NiMH version. Oddly, the tagless drop in batteries used by this
programmer were over twice the price of the solder tagged ones.

Naturally, I bought the cheaper tagged battery and pulled the tags
off
and dressed the 'pips' with a fine file to recreate the plug in
version
at less than half price for less than ten minutes of D-I-Y activity.
:-)

The 4.8 volts seems unusually high for battery backed memory though.
The
more usual with static cmos ram being 3.6 volts. CMOS sram is
guaranteed
to retain data integrity right down to the 2 volt point - and that
includes the RTCs with their 70 8 bit registers 'going spare' as
used by
IBM in their AT PCs first marketed back in August 1984).

--

Quad list it as a 4V battery - quite how they achieve that is another
question altogether!


--
Woody

harrogate3 at ntlworld dot com

On Wed, 24 Feb 2016 08:12:11 +0000, Woody wrote:

"Johnny B Good" wrote in message
...
On Sat, 20 Feb 2016 04:40:14 -0800, Phil Allison wrote:

RJH wrote:


Phil is right but I would wait until you have extracted it before
buying a replacement as it could be Ni-Cad or Ni-MH depending on
the age of the tuner, and they require slightly different charging
regimes. Equally it could be 3V, 3.6V or 4.8V although I would
admit that the size suggests the latter.


** AFAIK, Quad FM4s only ever used 4.8V NiCd battery packs with four
cells specially made for memory back-up. It was trickle charged at a
few mA whenever the tuner was powered up.

I doubt any re-engineering is needed to employ a four cell NiMH pack
instead.


Agreed, In fact, when I was looking for a replacement 3 cell NiCd for a
Potterton 2000 CH program controller, they'd changed to a larger
capacity NiMH version. Oddly, the tagless drop in batteries used by
this programmer were over twice the price of the solder tagged ones.

Naturally, I bought the cheaper tagged battery and pulled the tags off
and dressed the 'pips' with a fine file to recreate the plug in version
at less than half price for less than ten minutes of D-I-Y activity.
:-)

The 4.8 volts seems unusually high for battery backed memory though.
The more usual with static cmos ram being 3.6 volts. CMOS sram is
guaranteed to retain data integrity right down to the 2 volt point -
and that includes the RTCs with their 70 8 bit registers 'going spare'
as used by IBM in their AT PCs first marketed back in August 1984).

--

Quad list it as a 4V battery - quite how they achieve that is another
question altogether!

It might be the charger's nominal upper voltage limit for a 3 cell NiCd
(blue) or 3 cell NiMH (green) battery. Constant current charging of
either type results in a 'resting voltage' immediately after going off
charge in the region of 1.4 volts per cell, usually dropping to 1.36
volts after a day or two. The 1.2 volts rating for these cells is the
minimum voltage just prior to becoming exhausted of useful charge.

It's quite likely that a very simple blocking diode and current limiting
resistor charging circuit fed off the 5v logic supply is all that's being
used to keep the battery charged up just like the arrangement used on
early pre-Pentium PC motherboards to maintain the RTC battery backup
(typically a 3 cell 60mAH NiCd soldered onto the board).

If needs must, you could replace it with a lithium primary cell (3.1v)
and snip the resistor lead to disable the charging. Those CR2032 180mAH
coin cells now commonly used in PCs will keep the RTC running for
anywhere from 18 months in the case of the ****e PC Chips branded
motherboards right up to 5 years or more on the better quality brands of
motherboard. If you wire in one of those "Half AA" Lithium 'batteries' so
favoured by the manufacturers of smoke detectors guaranteed to last ten
years on their soldered in battery, I should imagine it will last a
couple of decades at least.

--
Johnny B Good

Johnny B Good wrote:


Quad list it as a 4V battery - quite how they achieve that is another
question altogether!


** Quad have " 4.8V NiCd " printed on the schem next to it.



It might be the charger's nominal upper voltage limit for a 3 cell NiCd
(blue) or 3 cell NiMH (green) battery. Constant current charging of
either type results in a 'resting voltage' immediately after going off
charge in the region of 1.4 volts per cell, usually dropping to 1.36
volts after a day or two. The 1.2 volts rating for these cells is the
minimum voltage just prior to becoming exhausted of useful charge.


** The rest voltage of a NiCd cell is 1.25V - under a moderate load it drops to 1.2v and is exhausted at 1.1V.

When trickle charged in memory back up use, there is just enough charge to compensate for internal self discharge - normally about C/50. So for a nominal 150mAh cell, that equates to a 3mA trickle charge.

A good condition, 4 cell pack ought to measure between 4.8 and 5V.

Same goes for NiMh cells.



..... Phil