Bulb replacement
 

Hi - can anyone identify this bulb:

http://tinyurl.com/3cf2h

from a Pioneer SX 750 receiver, late 70s model? It's about 3mm in diameter
and is used on the panel to indicate 'stereo'. And where to find a
replacement?

Many thanks

Rob

Bulb replacement
 

"RJH" wrote in message
...
Hi - can anyone identify this bulb:

http://tinyurl.com/3cf2h

from a Pioneer SX 750 receiver, late 70s model? It's about 3mm in diameter
and is used on the panel to indicate 'stereo'. And where to find a
replacement?

Many thanks

Rob



Check the polarity and voltage of the supply and replace it with a LED. The
negative side of the supply goes to the LED leg that has a small flat on the
LED body next to it.

You should have no difficulty in finding a suitably sized LED, but it will
need a current-limiting resistor in series. Take the supply voltage, deduct
2 and divide by 10. This will give the value of resistor in K-ohms needed.
E.g. suppose the supply is 12V, 12-2=10/10=1K. That will runs 10mA through
the LED which will be more than enough. If it is too bright try increasing
the resistor value by factors of 2 each time. The resistor will need to have
a power rating of 0.25W or higher. The resistor can go in either leg.


--

Woody

Bulb replacement
 

"Woody" wrote in message
...

"RJH" wrote in message
...
Hi - can anyone identify this bulb:

http://tinyurl.com/3cf2h

from a Pioneer SX 750 receiver, late 70s model? It's about 3mm in
diameter
and is used on the panel to indicate 'stereo'. And where to find a
replacement?

Many thanks

Rob



Check the polarity and voltage of the supply and replace it with a LED.
The
negative side of the supply goes to the LED leg that has a small flat on
the
LED body next to it.

You should have no difficulty in finding a suitably sized LED, but it will
need a current-limiting resistor in series. Take the supply voltage,
deduct
2 and divide by 10. This will give the value of resistor in K-ohms needed.
E.g. suppose the supply is 12V, 12-2=10/10=1K. That will runs 10mA through
the LED which will be more than enough. If it is too bright try increasing
the resistor value by factors of 2 each time. The resistor will need to
have
a power rating of 0.25W or higher. The resistor can go in either leg.


--

Woody



Many thanks for that Woody - I will give it a go. But, I can't figure out
what the voltage is!

I attached a voltmeter to the 2 wires coming out of one the lamps that work
('Power') and couldn't get it to measure much - it was switched on, the
voltmeter read a battery correctly, but no DC current on the bulb supply
except an occasional 0.3v - not steady though.

I clearly have no idea what I'm doing here so any further guidance
appreciated!

Rob

Bulb replacement
 

"RJH" wrote in message
...

"Woody" wrote in message
...

"RJH" wrote in message
...
Hi - can anyone identify this bulb:

http://tinyurl.com/3cf2h

from a Pioneer SX 750 receiver, late 70s model? It's about 3mm in
diameter
and is used on the panel to indicate 'stereo'. And where to find a
replacement?

Many thanks

Rob



Check the polarity and voltage of the supply and replace it with a LED.
The
negative side of the supply goes to the LED leg that has a small flat on
the
LED body next to it.

You should have no difficulty in finding a suitably sized LED, but it
will
need a current-limiting resistor in series. Take the supply voltage,
deduct
2 and divide by 10. This will give the value of resistor in K-ohms
needed.
E.g. suppose the supply is 12V, 12-2=10/10=1K. That will runs 10mA
through
the LED which will be more than enough. If it is too bright try
increasing
the resistor value by factors of 2 each time. The resistor will need to
have
a power rating of 0.25W or higher. The resistor can go in either leg.


--

Woody



Many thanks for that Woody - I will give it a go. But, I can't figure out
what the voltage is!

I attached a voltmeter to the 2 wires coming out of one the lamps that
work
('Power') and couldn't get it to measure much - it was switched on, the
voltmeter read a battery correctly, but no DC current on the bulb supply
except an occasional 0.3v - not steady though.

I clearly have no idea what I'm doing here so any further guidance
appreciated!

Rob


Just put your meter on volts across one of the bulbs. It is possible that
the power bulb is fed from a.c. hence why you get no reading. You can put a
stereo signal in off air and look across the dead bulb contacts - there may
be a small resistor in series but it won't matter. (Under-run a bulb by 10%
and you get 10x the life!) Don't try reading current - it is of no
consequence.

You can by the way buy those bulbs from spares outlets - they are known as
'pea' bulbs and are usually 6V or 12V. Again the supply volts should give an
indication, but if all else fails buy one of each and try the 12V first.


--

Woody

Bulb replacement
 

"RJH" wrote in message
...

"Woody" wrote in message
...

"RJH" wrote in message
...
Hi - can anyone identify this bulb:

http://tinyurl.com/3cf2h

from a Pioneer SX 750 receiver, late 70s model? It's about 3mm in
diameter
and is used on the panel to indicate 'stereo'. And where to find a
replacement?

Many thanks

Rob



Check the polarity and voltage of the supply and replace it with a LED.
The
negative side of the supply goes to the LED leg that has a small flat on
the
LED body next to it.

You should have no difficulty in finding a suitably sized LED, but it
will
need a current-limiting resistor in series. Take the supply voltage,
deduct
2 and divide by 10. This will give the value of resistor in K-ohms
needed.
E.g. suppose the supply is 12V, 12-2=10/10=1K. That will runs 10mA
through
the LED which will be more than enough. If it is too bright try
increasing
the resistor value by factors of 2 each time. The resistor will need to
have
a power rating of 0.25W or higher. The resistor can go in either leg.


--

Woody



Many thanks for that Woody - I will give it a go. But, I can't figure out
what the voltage is!

I attached a voltmeter to the 2 wires coming out of one the lamps that
work
('Power') and couldn't get it to measure much - it was switched on, the
voltmeter read a battery correctly, but no DC current on the bulb supply
except an occasional 0.3v - not steady though.

**The power lamp is probably run from the AC supply. You'll need to switch
your meter to 'AC' to measure anything. Also, be aware that the lamp in the
'STEREO' indicator may be of a different type and rating.


I clearly have no idea what I'm doing here so any further guidance
appreciated!

**Buy a 12 Volt lamp of the correct size and you'll be close to correct.
Alternatively, the replacement with an LED will also work. The only drawback
with using an LED is related to the radiation angle of the LED. Not all the
lettters (assuming the word 'STEREO' is illuminated when the unit is in
stereo) will be uniformly illuminated. I prefer to use Lumileds (much more
difficult to buy) for this purpose. They have a very wide radiation angle
(around 120o) and can cope with far higher currents.


--
Trevor Wilson
www.rageaudio.com.au

Bulb replacement
 

It is the bulb that's failed and not the driver circuitry?
Worth checking if all else fails........
Chris

Bulb replacement
 

"Chris O" wrote in message
...
It is the bulb that's failed and not the driver circuitry?
Worth checking if all else fails........

**Excellent point. If the PLL has drifted out of its lock zone, the Stereo
lamp will not light up. Unfortunately, he'll require a frequency counter to
check and adjust.


--
Trevor Wilson
www.rageaudio.com.au

Bulb replacement
 

"Trevor Wilson" wrote in message
...

"Chris O" wrote in message
...
It is the bulb that's failed and not the driver circuitry?
Worth checking if all else fails........

**Excellent point. If the PLL has drifted out of its lock zone, the Stereo
lamp will not light up. Unfortunately, he'll require a frequency counter
to
check and adjust.


--
Trevor Wilson
www.rageaudio.com.au

Many thanks (and to everyone else who replied earlier) - bit of lateral
thinking there! I'll check the bulb :-)

Rob

Bulb replacement
 

In article ,
Chris O wrote:
It is the bulb that's failed and not the driver circuitry?
Worth checking if all else fails........

I'd have said it easier to *listen* to see if it's in stereo. If you can't
tell the difference, then don't worry about the lamp. ;-)

--
*The most common name in the world is Mohammed *

Dave Plowman London SW 12
RIP Acorn