TX 6500 bright bulbs

[speakerfreak]

I'm in the process of replacing the dial bulbs. Ordered in 8 v 300 ma lamps from http://www.vintage-electronics.cc/vlamp.html and was almost blinded by them. Any idea what would cause it.

 

[dgwojo]

Are they the 8v/300ma wedge lamps?? I don't believe they test them before shipment so who knows what you actually received, I've run into this when 6.3v lamps are mixed up with 8v lamps in the same package from the factory. :sigh:

 

[speakerfreak]

They are bayonet style, They have 8v stamped on them. http://www.vintage-electronics.cc/images/bayonet.JPG

 

[johnnm]

If you're certain you ordered the right bulbs for the tuner, measure the voltage across it to see if it's really 8V. If slightly more voltage was applied, the bulb will glow brighter. (Add more and it'll just burn out real quickly.)
If it all checks out and you still think they're too bright (maybe your old ones were dirty?), considering adding a small resistor in series to bring the current down a bit.

 

[markthefixer]

That tuner runs the illumination and power lamps off of the traditional Pioneer 8v ac transformer winding, the illumination lamps are 8v 300mA, but the power light is a 6v 30mA with a 47 ohm dropping resistor.

Check to see if it has a multi-voltage switch in the back, and that it is set correctly for your line voltage (110 vs 120 etc..)

 

[jcnash]

This is some great information. Im sure a lot of people run into this problem due to bulbs with the required specs being unavailable.

So is the current a bigger concern than the voltage or vice versa? Lets say I use a 6v 300mA bulb and an 8V 100mA bulb instead of an 8V 300mA bulb, which would burn out first?

I ask because I am looking for some wedge type bulbs (8V 300MA) for a SX-880 and can only find the 6V 300mA bulbs. I was considering resorting to soldering the wires onto a standard bayonet type bulb, but id rather use the original wedge type mounts.

 

[markthefixer]

This is some great information. Im sure a lot of people run into this problem due to bulbs with the required specs being unavailable.

So is the current a bigger concern than the voltage or vice versa? Lets say I use a 6v 300mA bulb and an 8V 100mA bulb instead of an 8V 300mA bulb, which would burn out first?

I ask because I am looking for some wedge type bulbs (8V 300MA) for a SX-880 and can only find the 6V 300mA bulbs. I was considering resorting to soldering the wires onto a standard bayonet type bulb, but id rather use the original wedge type mounts.

The voltage is the over-riding concern. a 6v bulb running on 8v will go out in a flash of glory, and the question of a series resistor at higher currents becomes problematic:

dropping 2 volts at 300ma needs 6.67 ohms and 0.6 watts (use a 1 watt) dissipation.

(edit: dropping 2 volts at 100mA needs 20 ohms and 0.2 watts (use a 1/2 watt) dissipation - so you see the lamp current is CRITICAL for getting the RIGHT series resistor value to get the correct voltage drop - to keep from burning out the bulb)

When the voltage is correct (8v 300mA vs 8v 100mA) the lower current just means it's not as "bright".

The "gotcha" is when the circuit already uses a series resistor to drop the voltage, because a change in current will upset the original calculations that were done to get the correct voltage.

THAT added series resistor can be detected by measuring the voltage across a dead lamp - the high impedance of the voltmeter means the voltage drop across the series resistor will be nil.
(edit: thus you will "see" 32v at an 8v lamp location.)

Or of course - read the schematic or trace the circuit.

There are, of course even WEIRDER Pioneer exceptions to this that I can think of offhand.

 

[aldena007]

I have a question about setting the proper power on multivoltage units. Markthefixer mentioned 110 and 120 volts. Which is the official voltage for the US particluarly residential. Or is the better way to test what is present at the wall socket and set the unit to the closest value?

 

[markthefixer]

I have a question about setting the proper power on multivoltage units. Markthefixer mentioned 110 and 120 volts. Which is the official voltage for the US particluarly residential. Or is the better way to test what is present at the wall socket and set the unit to the closest value?

USA is usually 120v, when in doubt - read the wall socket with DMM set appropriately.


120v into a 110v setting gives 8.73v instead of 8v.

 

[jcnash]

The voltage is the over-riding concern. a 6v bulb running on 8v will go out in a flash of glory, and the question of a series resistor at higher currents becomes problematic:

dropping 2 volts at 300ma needs 6.67 ohms and 0.6 watts (use a 1 watt) dissipation.

When the voltage is correct (8v 300mA vs 8v 100mA) the lower current just means it's not as "bright".

The "gotcha" is when the circuit already uses a series resistor to drop the voltage, because a change in current will upset the original calculations that were done to get the correct voltage.

THAT added series resistor can be detected by measuring the voltage across a dead lamp - the high impedance of the voltmeter means the voltage drop across the series resistor will be nil.

Or of course - read the schematic or trace the circuit.

There are, of course even WEIRDER Pioneer exceptions to this that I can think of offhand.

Thanks Mark.

That clarified a question which has been running in my head for YEARS, just waiting for the right opportunity to come up to get clarified.

 

[dgwojo]

They are bayonet style, They have 8v stamped on them. http://www.vintage-electronics.cc/images/bayonet.JPG

I've run into a batch of mismarked 8v/300ma bayonets, my bet is you also have encountered them, I wouldn't use them, Dave. :thumbsdn:

 

[speakerfreak]

I've run into a batch of mismarked 8v/300ma bayonets, my bet is you also have encountered them, I wouldn't use them, Dave. :thumbsdn:

Yep, costly mistake but hey.... I'm learning.

brought a few pinball 44 bulbs home from work, they are a bit brighter but not blinding.

 

[speakerfreak]

Thanks to dgwojo Who Helped me find the correct bulbs and no thanks to Bob at Vintage Electronics Sales who wouldn't believe that their bayonet bulbs were wrong.

 

[markthefixer]

Shame on him, it's SOOOOO easy to grab a variable power supply and ramp up the voltage until the correct current is reached, THEN check the voltage. IT's NOT his fault or dishonor that the lamp manufacturer screwed up and screwed him and Dave, but if he doesn't bother to double check after being told.... that would be his fault.

I'd be willing to bet that the manufacturer and distributor well know about the goof, and should be willing to rectify the situation.

How bout it Dave? Was the lamp distributor all soggy and hard to light?

 

[speakerfreak]

Dave is wonderful!!

Shame on him, it's SOOOOO easy to grab a variable power supply and ramp up the voltage until the correct current is reached, THEN check the voltage. IT's NOT his fault or dishonor that the lamp manufacturer screwed up and screwed him and Dave, but if he doesn't bother to double check after being told.... that would be his fault.

I'd be willing to bet that the manufacturer and distributor well know about the goof, and should be willing to rectify the situation.

How bout it Dave? Was the lamp distributor all soggy and hard to light?

 

[markthefixer]

Thanks to dgwojo Who Helped me find the correct bulbs and no thanks to Bob at Vintage Electronics Sales who wouldn't believe that their bayonet bulbs were wrong.

Shame on him, it's SOOOOO easy to grab a variable power supply and ramp up the voltage until the correct current is reached, THEN check the voltage. IT's NOT his fault or dishonor that the lamp manufacturer screwed up and screwed him and Dave, but if he doesn't bother to double check after being told.... that would be his fault.

I'd be willing to bet that the manufacturer and distributor well know about the goof, and should be willing to rectify the situation.

How bout it Dave? Was the lamp distributor all soggy and hard to light?

Dave is wonderful!! It's Bob I'm not happy with

I know that...

 

[dgwojo]

I'd be willing to bet that the manufacturer and distributor well know about the goof, and should be willing to rectify the situation.

How bout it Dave? Was the lamp distributor all soggy and hard to light?

I received about 10 of them a few years ago and just threw them in a drawer figuring I'd use them for something else, never bothered to chase the issue down since I already knew the whole supply of them was most likely bad.

 

[speakerfreak]

Funny thing is, we tested them last night and they meter out at 8 and 300 but still blindingly bright. :scratch2:

 

[Transceiver]

Hello.

I just stumbled accross this thread while searching online for the same problem. Last week I ordered a dozen 8v 300ma bayonet lamps from vintage-electronics.net for an SX-450 which I'm rebuilding for a customer, I've retrofitted bayonet holders into the original silicone holders to take the bayonet bases.

Yesterday I received the lamps, these lamps are running very bright and HOT, within 5 minutes I had one lamp blow and over the space of under an hour with the lid off, a further two blew. I've done a full rebuild/recap of this receiver and it's in perfect shape, I'm getting a steady 7.75v accross the lamp terminals and the 50ma power indicator lamp which runs from the same supply is running fine - just to confirm to them that it's definitely not a power supply problem. These lamps are stamped as 8v but by the colour of the filaments alone you can see they're being overrun by quite a margin, my first thought was that they looked like 6v lamps judging by how bright they were.

Getting these shipped to the UK isn't cheap, if I have to order another set of lamps from the US it also means my customer has to wait another week or so for a receiver which in all other respects is ready to be shipped back to them. I sent vintage-electronics.net a polite email yesterday evening, basically a copy/paste of what I've written above. In this case I've been offered a refund if I send them back, which I'll probably do out of principle alone - I'll let you know if that happens.

I realise this thread is 2 months old but thought I'd let you all know the dud lamps are still being sold.


Cheers, Bruce.

 

[markthefixer]

Thanks for the heads-up! Welcome to AK!!!

Always glad to hear from someone on the other side of "the pond"....
(it's always hard to recommend parts "there" when I'm "here", for other folks)

Have a look around, hope you like what you see and visit regularly.

Do you have a day job, or is this it?