I have this old fluorescent desk lamp from the 60s at the latest that I'm fixing. It weighs a ton, has been passed down from my father-in-law, and it just retro-cool. According to him it's always worked, except the F15-T8 bulbs are possibly original and very worn out, and only one bulb ever lights. I've been told this has always been a problem, and holding the start button for a long time will sometimes get both to start. I've never been successful but I don't like this and want to fix it.

Upon reverse engineering it I come up with this schematic (it's rough, drawn in Paint!):


https://imgur.com/a/0YYKV

I'm no fluorescent light expert, but how the start button is connected to both lamps seems odd to me, a little like directly paralleling LEDs or neon bulbs after the limit resistor. If I disconnect one bulb, the remaining always starts. I doubt this design would ever work very well....would it?

If I manually start each light by disconnecting the start button wires and momentarily shorting the two pins at opposite ends of each lamp, they each start right up. My plan is to modify it with a DPDT relay with 120VAC coil so the start button drives the coil, and each lamp has it's own set of relay contacts. I'm sure this will work, but.....WTF with the original design? Is this normal? I doubt it's even been modified, and see no good way to fix it without adding a relay or a multipole start switch.

I'm a little surprised to see some that seems this hokey (to me) in something this old.

On 10/8/2017 9:55 PM, wrote:
I have this old fluorescent desk lamp from the 60s at the latest that I'm fixing. It weighs a ton, has been passed down from my father-in-law, and it just retro-cool. According to him it's always worked, except the F15-T8 bulbs are possibly original and very worn out, and only one bulb ever lights. I've been told this has always been a problem, and holding the start button for a long time will sometimes get both to start. I've never been successful but I don't like this and want to fix it.

Upon reverse engineering it I come up with this schematic (it's rough, drawn in Paint!):


https://imgur.com/a/0YYKV

I'm no fluorescent light expert, but how the start button is connected to both lamps seems odd to me, a little like directly paralleling LEDs or neon bulbs after the limit resistor. If I disconnect one bulb, the remaining always starts. I doubt this design would ever work very well....would it?

If I manually start each light by disconnecting the start button wires and momentarily shorting the two pins at opposite ends of each lamp, they each start right up. My plan is to modify it with a DPDT relay with 120VAC coil so the start button drives the coil, and each lamp has it's own set of relay contacts. I'm sure this will work, but.....WTF with the original design? Is this normal? I doubt it's even been modified, and see no good way to fix it without adding a relay or a multipole start switch.

I'm a little surprised to see some that seems this hokey (to me) in something this old.

Check connections and/or new tubes new ballasts.

On 9/10/2017 9:55 AM, wrote:
I have this old fluorescent desk lamp from the 60s at the latest that I'm fixing. It weighs a ton, has been passed down from my father-in-law, and it just retro-cool. According to him it's always worked, except the F15-T8 bulbs are possibly original and very worn out, and only one bulb ever lights. I've been told this has always been a problem, and holding the start button for a long time will sometimes get both to start. I've never been successful but I don't like this and want to fix it.

Upon reverse engineering it I come up with this schematic (it's rough, drawn in Paint!):


https://imgur.com/a/0YYKV

I'm no fluorescent light expert, but how the start button is connected to both lamps seems odd to me, a little like directly paralleling LEDs or neon bulbs after the limit resistor. If I disconnect one bulb, the remaining always starts. I doubt this design would ever work very well....would it?

If I manually start each light by disconnecting the start button wires and momentarily shorting the two pins at opposite ends of each lamp, they each start right up. My plan is to modify it with a DPDT relay with 120VAC coil so the start button drives the coil, and each lamp has it's own set of relay contacts. I'm sure this will work, but.....WTF with the original design? Is this normal? I doubt it's even been modified, and see no good way to fix it without adding a relay or a multipole start switch.

I'm a little surprised to see some that seems this hokey (to me) in something this old.

Like Tom said also change the tubes over and see if its the one tube U/s

On 2017/10/08 6:55 PM, wrote:
I have this old fluorescent desk lamp from the 60s at the latest that I'm fixing. It weighs a ton, has been passed down from my father-in-law, and it just retro-cool. According to him it's always worked, except the F15-T8 bulbs are possibly original and very worn out, and only one bulb ever lights. I've been told this has always been a problem, and holding the start button for a long time will sometimes get both to start. I've never been successful but I don't like this and want to fix it.

Upon reverse engineering it I come up with this schematic (it's rough, drawn in Paint!):


https://imgur.com/a/0YYKV

Normal old style start circuit where a 'starter' is not used. This
circuit is found on desk/counter fluorescent lights where you pushed a
button to light the tube, after holding the button for a second or two.
Button switch is momentary on.


I'm no fluorescent light expert, but how the start button is connected to both lamps seems odd to me, a little like directly paralleling LEDs or neon bulbs after the limit resistor. If I disconnect one bulb, the remaining always starts. I doubt this design would ever work very well....would it?

The bulbs are independent of each other (even though the start windings
are shorted together for starting) - each has a ballast. I would expect
that the tube that doesn't light has a bad ballast. Did you exchange the
bulbs to see if the good one lights in the other position? It may also
be that the tube connector pins are bent or a broken connection. Use an
ohm-meter to check continuity with only one bulb installed at a time.


If I manually start each light by disconnecting the start button wires and momentarily shorting the two pins at opposite ends of each lamp, they each start right up. My plan is to modify it with a DPDT relay with 120VAC coil so the start button drives the coil, and each lamp has it's own set of relay contacts. I'm sure this will work, but.....WTF with the original design? Is this normal? I doubt it's even been modified, and see no good way to fix it without adding a relay or a multipole start switch.

I'm a little surprised to see some that seems this hokey (to me) in something this old.


This light was just after WWII is my guess, and starters were not always
used.

If you need a 15watt ballast they are around $10US - you want the
two-wire version. We use these in jukeboxes and arcade games.

John :-#)#

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On Monday, 9 October 2017 02:55:28 UTC+1, wrote:

I have this old fluorescent desk lamp from the 60s at the latest that I'm fixing. It weighs a ton, has been passed down from my father-in-law, and it just retro-cool. According to him it's always worked, except the F15-T8 bulbs are possibly original and very worn out, and only one bulb ever lights.. I've been told this has always been a problem, and holding the start button for a long time will sometimes get both to start. I've never been successful but I don't like this and want to fix it.

Upon reverse engineering it I come up with this schematic (it's rough, drawn in Paint!):


https://imgur.com/a/0YYKV

I'm no fluorescent light expert, but how the start button is connected to both lamps seems odd to me, a little like directly paralleling LEDs or neon bulbs after the limit resistor. If I disconnect one bulb, the remaining always starts. I doubt this design would ever work very well....would it?

If I manually start each light by disconnecting the start button wires and momentarily shorting the two pins at opposite ends of each lamp, they each start right up. My plan is to modify it with a DPDT relay with 120VAC coil so the start button drives the coil, and each lamp has it's own set of relay contacts. I'm sure this will work, but.....WTF with the original design? Is this normal? I doubt it's even been modified, and see no good way to fix it without adding a relay or a multipole start switch.

I'm a little surprised to see some that seems this hokey (to me) in something this old.

The circuit is a right bodge. The 2 tubes are connected in parallel, the lit one will be taking around twice its rated run current.


NT

I should clarify a few things.

-I already purchased new bulbs. The old ones worked but were very dim.

-The ballasts each measure about 30 ohms. I have not yet put an inductance meter on them but my guess is they are good.

-I connected the bulbs using jumper wires to eliminate bad connections in the sockets. No change.

-If I install only one bulb with everything wired as it originally was, that one always starts. If I remove it and install the other bulb in the other bulb socket pair, that one also always starts. With both in circuit, I've never seen them both start, only one does.

-With both bulbs in circuit one specific bulb tends to start, but randomly the other does instead.

-If I separate out each bulb-ballast circuit so they look like completely independent fixtures and start each manually by temporarily shorting the one bulb pin at each end, each starts and runs no problem. So that's why I believe both ballasts are good.

The part of the original circuit I'm having trouble dealing with is how the bulbs are permanently connected at the same end as the ballast connection. It seems one bulb could steal the start pulse from both ballasts, hence the reason for the issue. But then again this was designed this way and supposedly would work?

I have a DPDT relay on the way to isolate each starting switch and that will fix it, but did these desk lamps ever intend to work correctly? Seems odd..

On 2017/10/09 4:29 AM, wrote:
I should clarify a few things.

-I already purchased new bulbs. The old ones worked but were very dim.

I suspect you have Rapid Start bulbs that are self starting. What is the
code number of the bulbs you used?


-The ballasts each measure about 30 ohms. I have not yet put an inductance meter on them but my guess is they are good.

A quick ballast test is to power up the fixture then read the ballast
side against the other side of the line - should be around 130VAC. If it
show 115 (or whatever your AC source is) then the ballast is bad.


-I connected the bulbs using jumper wires to eliminate bad connections in the sockets. No change.

-If I install only one bulb with everything wired as it originally was, that one always starts. If I remove it and install the other bulb in the other bulb socket pair, that one also always starts. With both in circuit, I've never seen them both start, only one does.

Try grounding the metal frame of the fixture. Or if grounded (someone
would have added that, wouldn't have been there originally), remove the
ground


-With both bulbs in circuit one specific bulb tends to start, but randomly the other does instead.

-If I separate out each bulb-ballast circuit so they look like completely independent fixtures and start each manually by temporarily shorting the one bulb pin at each end, each starts and runs no problem. So that's why I believe both ballasts are good.

True.


The part of the original circuit I'm having trouble dealing with is how the bulbs are permanently connected at the same end as the ballast connection. It seems one bulb could steal the start pulse from both ballasts, hence the reason for the issue. But then again this was designed this way and supposedly would work?

The bulbs are only connected to the non-ballast line side when the
button is pressed. Otherwise the interconnections can't conduct current
as they are on the same side of the line for each bulb.


I have a DPDT relay on the way to isolate each starting switch and that will fix it, but did these desk lamps ever intend to work correctly? Seems odd..

Why not use a DPDT push button switch? While I don't think it will
change anything it can be wired to isolate the two bulbs from each other
more easily than fitting a relay in there.



It is odd, I agree, that both bulbs won't light if everything is as
described. They should. You do press and hold the button until the ends
of the tubes glow for a second, right?

John :-#)#

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"Old pinballers never die, they just flip out."

On Monday, October 9, 2017 at 9:13:34 AM UTC-5, John Robertson wrote:
On 2017/10/09 4:29 AM, @yahoo.com wrote:
I should clarify a few things.

-I already purchased new bulbs. The old ones worked but were very dim.

I suspect you have Rapid Start bulbs that are self starting. What is the
code number of the bulbs you used?


It's item# 147940 from Lowe's, and the specs say they are not rapid start.


-The ballasts each measure about 30 ohms. I have not yet put an inductance meter on them but my guess is they are good.

A quick ballast test is to power up the fixture then read the ballast
side against the other side of the line - should be around 130VAC. If it
show 115 (or whatever your AC source is) then the ballast is bad.


-I connected the bulbs using jumper wires to eliminate bad connections in the sockets. No change.

-If I install only one bulb with everything wired as it originally was, that one always starts. If I remove it and install the other bulb in the other bulb socket pair, that one also always starts. With both in circuit, I've never seen them both start, only one does.

Try grounding the metal frame of the fixture. Or if grounded (someone
would have added that, wouldn't have been there originally), remove the
ground


Interesting. It does have the original cord but I've considered putting a grounded cord on there because I started wondering about the safety of this thing should something internally touch the enclosure. For what it's worth, is does the same even with the innards laying out on a table.


-With both bulbs in circuit one specific bulb tends to start, but randomly the other does instead.

-If I separate out each bulb-ballast circuit so they look like completely independent fixtures and start each manually by temporarily shorting the one bulb pin at each end, each starts and runs no problem. So that's why I believe both ballasts are good.

True.


The part of the original circuit I'm having trouble dealing with is how the bulbs are permanently connected at the same end as the ballast connection. It seems one bulb could steal the start pulse from both ballasts, hence the reason for the issue. But then again this was designed this way and supposedly would work?

The bulbs are only connected to the non-ballast line side when the
button is pressed. Otherwise the interconnections can't conduct current
as they are on the same side of the line for each bulb.


I was most concerned about the ballast side of the bulbs where they essentially connect together through the heater/filament even when start isn't pressed. That seems like not such a good design and maybe why the problem is occurring.


I have a DPDT relay on the way to isolate each starting switch and that will fix it, but did these desk lamps ever intend to work correctly? Seems odd..

Why not use a DPDT push button switch? While I don't think it will
change anything it can be wired to isolate the two bulbs from each other
more easily than fitting a relay in there.


That's what I first looked at, but the relay was much cheaper and most importantly, keeps the outward appearance the same. There's also plenty of room inside this thing.



It is odd, I agree, that both bulbs won't light if everything is as
described. They should. You do press and hold the button until the ends
of the tubes glow for a second, right?


Oh yeah. I pressed and held it, and both ends of both bulbs begin glowing white. When I release it, one lights, and the other has this very dim flicker that decays within a few seconds. The interesting thing is one end of one bulb randomly flickers while holding start. Now whether that's the one that doesn't start, I didn't think to observe until now.

John :-#)#

--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd.
MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
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www.flippers.com
"Old pinballers never die, they just flip out."

On 10/9/2017 11:31 AM, wrote:
On Monday, October 9, 2017 at 9:13:34 AM UTC-5, John Robertson wrote:
On 2017/10/09 4:29 AM, @yahoo.com wrote:
I should clarify a few things.

-I already purchased new bulbs. The old ones worked but were very dim.

I suspect you have Rapid Start bulbs that are self starting. What is the
code number of the bulbs you used?


It's item# 147940 from Lowe's, and the specs say they are not rapid start.


-The ballasts each measure about 30 ohms. I have not yet put an inductance meter on them but my guess is they are good.

A quick ballast test is to power up the fixture then read the ballast
side against the other side of the line - should be around 130VAC. If it
show 115 (or whatever your AC source is) then the ballast is bad.


-I connected the bulbs using jumper wires to eliminate bad connections in the sockets. No change.

-If I install only one bulb with everything wired as it originally was, that one always starts. If I remove it and install the other bulb in the other bulb socket pair, that one also always starts. With both in circuit, I've never seen them both start, only one does.

Try grounding the metal frame of the fixture. Or if grounded (someone
would have added that, wouldn't have been there originally), remove the
ground


Interesting. It does have the original cord but I've considered putting a grounded cord on there because I started wondering about the safety of this thing should something internally touch the enclosure. For what it's worth, is does the same even with the innards laying out on a table.


-With both bulbs in circuit one specific bulb tends to start, but randomly the other does instead.

-If I separate out each bulb-ballast circuit so they look like completely independent fixtures and start each manually by temporarily shorting the one bulb pin at each end, each starts and runs no problem. So that's why I believe both ballasts are good.

True.


The part of the original circuit I'm having trouble dealing with is how the bulbs are permanently connected at the same end as the ballast connection. It seems one bulb could steal the start pulse from both ballasts, hence the reason for the issue. But then again this was designed this way and supposedly would work?

The bulbs are only connected to the non-ballast line side when the
button is pressed. Otherwise the interconnections can't conduct current
as they are on the same side of the line for each bulb.


I was most concerned about the ballast side of the bulbs where they essentially connect together through the heater/filament even when start isn't pressed. That seems like not such a good design and maybe why the problem is occurring.


I have a DPDT relay on the way to isolate each starting switch and that will fix it, but did these desk lamps ever intend to work correctly? Seems odd..

Why not use a DPDT push button switch? While I don't think it will
change anything it can be wired to isolate the two bulbs from each other
more easily than fitting a relay in there.


That's what I first looked at, but the relay was much cheaper and most importantly, keeps the outward appearance the same. There's also plenty of room inside this thing.



It is odd, I agree, that both bulbs won't light if everything is as
described. They should. You do press and hold the button until the ends
of the tubes glow for a second, right?


Oh yeah. I pressed and held it, and both ends of both bulbs begin glowing white. When I release it, one lights, and the other has this very dim flicker that decays within a few seconds. The interesting thing is one end of one bulb randomly flickers while holding start. Now whether that's the one that doesn't start, I didn't think to observe until now.

John :-#)#

--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd.
MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
(604)872-5757 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

This may sound stupid but did you check you line voltage where you are
doing this testing?

On Monday, October 9, 2017 at 10:56:17 AM UTC-5, Tom Biasi wrote:
On 10/9/2017 11:31 AM, @yahoo.com wrote:
On Monday, October 9, 2017 at 9:13:34 AM UTC-5, John Robertson wrote:
On 2017/10/09 4:29 AM, @yahoo.com wrote:
I should clarify a few things.

-I already purchased new bulbs. The old ones worked but were very dim..

I suspect you have Rapid Start bulbs that are self starting. What is the
code number of the bulbs you used?


It's item# 147940 from Lowe's, and the specs say they are not rapid start.


-The ballasts each measure about 30 ohms. I have not yet put an inductance meter on them but my guess is they are good.

A quick ballast test is to power up the fixture then read the ballast
side against the other side of the line - should be around 130VAC. If it
show 115 (or whatever your AC source is) then the ballast is bad.


-I connected the bulbs using jumper wires to eliminate bad connections in the sockets. No change.

-If I install only one bulb with everything wired as it originally was, that one always starts. If I remove it and install the other bulb in the other bulb socket pair, that one also always starts. With both in circuit, I've never seen them both start, only one does.

Try grounding the metal frame of the fixture. Or if grounded (someone
would have added that, wouldn't have been there originally), remove the
ground


Interesting. It does have the original cord but I've considered putting a grounded cord on there because I started wondering about the safety of this thing should something internally touch the enclosure. For what it's worth, is does the same even with the innards laying out on a table.


-With both bulbs in circuit one specific bulb tends to start, but randomly the other does instead.

-If I separate out each bulb-ballast circuit so they look like completely independent fixtures and start each manually by temporarily shorting the one bulb pin at each end, each starts and runs no problem. So that's why I believe both ballasts are good.

True.


The part of the original circuit I'm having trouble dealing with is how the bulbs are permanently connected at the same end as the ballast connection. It seems one bulb could steal the start pulse from both ballasts, hence the reason for the issue. But then again this was designed this way and supposedly would work?

The bulbs are only connected to the non-ballast line side when the
button is pressed. Otherwise the interconnections can't conduct current
as they are on the same side of the line for each bulb.


I was most concerned about the ballast side of the bulbs where they essentially connect together through the heater/filament even when start isn't pressed. That seems like not such a good design and maybe why the problem is occurring.


I have a DPDT relay on the way to isolate each starting switch and that will fix it, but did these desk lamps ever intend to work correctly? Seems odd..

Why not use a DPDT push button switch? While I don't think it will
change anything it can be wired to isolate the two bulbs from each other
more easily than fitting a relay in there.


That's what I first looked at, but the relay was much cheaper and most importantly, keeps the outward appearance the same. There's also plenty of room inside this thing.



It is odd, I agree, that both bulbs won't light if everything is as
described. They should. You do press and hold the button until the ends
of the tubes glow for a second, right?


Oh yeah. I pressed and held it, and both ends of both bulbs begin glowing white. When I release it, one lights, and the other has this very dim flicker that decays within a few seconds. The interesting thing is one end of one bulb randomly flickers while holding start. Now whether that's the one that doesn't start, I didn't think to observe until now.

John :-#)#

--
(Please post followups or tech inquiries to the USENET newsgroup)
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MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
(604)872-5757 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

This may sound stupid but did you check you line voltage where you are
doing this testing?

It's near 120VAC as it should be. It's in my house plugged into a regular outlet.

On 2017/10/09 8:31 AM, wrote:
On Monday, October 9, 2017 at 9:13:34 AM UTC-5, John Robertson wrote:
On 2017/10/09 4:29 AM, @yahoo.com wrote:
I should clarify a few things.

-I already purchased new bulbs. The old ones worked but were very dim.

I suspect you have Rapid Start bulbs that are self starting. What is the
code number of the bulbs you used?


It's item# 147940 from Lowe's, and the specs say they are not rapid start.


-The ballasts each measure about 30 ohms. I have not yet put an inductance meter on them but my guess is they are good.

A quick ballast test is to power up the fixture then read the ballast
side against the other side of the line - should be around 130VAC. If it
show 115 (or whatever your AC source is) then the ballast is bad.


-I connected the bulbs using jumper wires to eliminate bad connections in the sockets. No change.

-If I install only one bulb with everything wired as it originally was, that one always starts. If I remove it and install the other bulb in the other bulb socket pair, that one also always starts. With both in circuit, I've never seen them both start, only one does.

Try grounding the metal frame of the fixture. Or if grounded (someone
would have added that, wouldn't have been there originally), remove the
ground


Interesting. It does have the original cord but I've considered putting a grounded cord on there because I started wondering about the safety of this thing should something internally touch the enclosure. For what it's worth, is does the same even with the innards laying out on a table.


-With both bulbs in circuit one specific bulb tends to start, but randomly the other does instead.

-If I separate out each bulb-ballast circuit so they look like completely independent fixtures and start each manually by temporarily shorting the one bulb pin at each end, each starts and runs no problem. So that's why I believe both ballasts are good.

True.


The part of the original circuit I'm having trouble dealing with is how the bulbs are permanently connected at the same end as the ballast connection. It seems one bulb could steal the start pulse from both ballasts, hence the reason for the issue. But then again this was designed this way and supposedly would work?

The bulbs are only connected to the non-ballast line side when the
button is pressed. Otherwise the interconnections can't conduct current
as they are on the same side of the line for each bulb.


I was most concerned about the ballast side of the bulbs where they essentially connect together through the heater/filament even when start isn't pressed. That seems like not such a good design and maybe why the problem is occurring.


I have a DPDT relay on the way to isolate each starting switch and that will fix it, but did these desk lamps ever intend to work correctly? Seems odd..

Why not use a DPDT push button switch? While I don't think it will
change anything it can be wired to isolate the two bulbs from each other
more easily than fitting a relay in there.


That's what I first looked at, but the relay was much cheaper and most importantly, keeps the outward appearance the same. There's also plenty of room inside this thing.

I think your assessment is correct, that the two lamps that have the
ballast side of their filaments connected together may be the problem.
It is odd as I'm sure thousands of these lights were made and would have
worked correctly with the wiring as you showed.

Let's see what happens once you get the relay wired in.




It is odd, I agree, that both bulbs won't light if everything is as
described. They should. You do press and hold the button until the ends
of the tubes glow for a second, right?


Oh yeah. I pressed and held it, and both ends of both bulbs begin glowing white. When I release it, one lights, and the other has this very dim flicker that decays within a few seconds. The interesting thing is one end of one bulb randomly flickers while holding start. Now whether that's the one that doesn't start, I didn't think to observe until now.

Randomly flickering on one bulb when the start is pressed suggests a
problem with a connection to the bulb. I'd look into that more.

More info on fluorescent lamps that you will ever need to know, but they
talk about lag time which may have a bearing...

http://sound.whsites.net/lamps/fluorescent.html

John :-#)#


--
(Please post followups or tech inquiries to the USENET newsgroup)
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MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
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www.flippers.com
"Old pinballers never die, they just flip out."

On Monday, 9 October 2017 16:31:18 UTC+1, wrote:
On Monday, October 9, 2017 at 9:13:34 AM UTC-5, John Robertson wrote:
On 2017/10/09 4:29 AM, @yahoo.com wrote:
I should clarify a few things.

-I already purchased new bulbs. The old ones worked but were very dim..

I suspect you have Rapid Start bulbs that are self starting. What is the
code number of the bulbs you used?


It's item# 147940 from Lowe's, and the specs say they are not rapid start.

On 09.10.2017 03:55, wrote:
I have this old fluorescent desk lamp from the 60s at the latest
that I'm fixing. It weighs a ton, has been passed down from my
father-in-law, and it just retro-cool. According to him it's always
worked, except the F15-T8 bulbs are possibly original and very worn
out, and only one bulb ever lights. I've been told this has always
been a problem, and holding the start button for a long time will
sometimes get both to start. I've never been successful but I don't
like this and want to fix it.

Upon reverse engineering it I come up with this schematic (it's
rough, drawn in Paint!):


https://imgur.com/a/0YYKV

I'm no fluorescent light expert, but how the start button is
connected to both lamps seems odd to me, a little like directly
paralleling LEDs or neon bulbs after the limit resistor. If I
disconnect one bulb, the remaining always starts. I doubt this
design would ever work very well....would it?

....


This circuit is indeed rather unreliable, one lamp will always fail to
start. The reason is that the filaments have a rather low resistance and
as soon as one discharge is ionized, it will steal the remaining start
pulse from the other lamp through the filament resistance. It will also
overload the lamp that works because additional current will be driven
into it through the other lamp's filament.

There are at least 3 ways to fix this (roughly in order of usefulness):

1. Change the SPST start button to a DPST one, use one pole per lamp.

2. Keep the SPST button but add a DPST relay to start the lamps via the
relay contacts and use the button to energize the relay coil.

3. Put a center-tapped inductor between the lamps as shown he

https://imgur.com/a/lCoNK

This will present a low impedance to the preheat current (inductor has
opposite-phase windings, being essentially shorted) but a much higher
impedance to the ignition pulse (inductor has in-phase windings, being
essentially open to high frequency components from a pulse). The 1kV
varistor is only there to protect the switch contacts from arcing.

Been reading this thread.

https://www.1000bulbs.com/product/36...xoCmwcQAvD_BwE

Would one of these fit? If so, install one, pick the lamps you want - and be done with it. All the nostalgia, but fully functional and less energy used.

Peter Wieck
Melrose Park, PA

On Wednesday, 11 October 2017 13:23:16 UTC+1, wrote:
Been reading this thread.

https://www.1000bulbs.com/product/36...xoCmwcQAvD_BwE

Would one of these fit? If so, install one, pick the lamps you want - and be done with it. All the nostalgia, but fully functional and less energy used.

Peter Wieck
Melrose Park, PA

Why do some people rip long lived original stuff out of historic items, fit junk instead, and pay for doing so? Senseless.


NT

On Wednesday, October 11, 2017 at 8:33:07 AM UTC-4, wrote:


Why do some people rip long lived original stuff out of historic items, fit junk instead, and pay for doing so? Senseless.


NT

Long-lived? Sure, the ballast may be long-lived - it is essentially a step-up only device, but the consumables that go with it lasted a fraction of what a modern lamp will last, used far more power and give far less light per watt.

So, about 12,000 hours (at best) vs. about 32,000 hours (on average) of longevity.
CRI of 69 vs. up to 96.
34 watts (at best) to as little as 25 watts for equivalent output.
Much better aging.

Seems like a pretty simple choice to me. I would prefer to keep my money for other things than wasting it needlessly on power.

Peter Wieck
Melrose Park, PA

On Wednesday, 11 October 2017 13:46:10 UTC+1, wrote:
On Wednesday, October 11, 2017 at 8:33:07 AM UTC-4, tabby wrote:


Why do some people rip long lived original stuff out of historic items, fit junk instead, and pay for doing so? Senseless.

Long-lived? Sure, the ballast may be long-lived - it is essentially a step-up only device, but the consumables that go with it lasted a fraction of what a modern lamp will last, used far more power and give far less light per watt.

So, about 12,000 hours (at best) vs. about 32,000 hours (on average) of longevity.
CRI of 69 vs. up to 96.
34 watts (at best) to as little as 25 watts for equivalent output.
Much better aging.

Seems like a pretty simple choice to me. I would prefer to keep my money for other things than wasting it needlessly on power.

Peter Wieck
Melrose Park, PA

That seems confused. I was talking about the ballasts, which obviously do not need replacing. The tubes you refer to are hardly likely to be original, and even if they are replacing them won't save any power or money. All the OP needs is a 2 pole switch or relay.


NT

On Thursday, October 12, 2017 at 9:15:11 AM UTC-4, wrote:

That seems confused. I was talking about the ballasts, which obviously do not need replacing. The tubes you refer to are hardly likely to be original, and even if they are replacing them won't save any power or money. All the OP needs is a 2 pole switch or relay.


It is the ballasts that drive the consumables. Magnetic ballasts of that vintage cannot handle T8 or T5 lamps, some cannot even handle high-efficiency T12 lamps. They also require manual-start switch systems which further degrades the lamps. They also consume considerable power in their own right.

A "smart" electronic ballast will adapt to various lamp options, consumes 30% less power, and will very nearly triple the longevity of the lamps and halve the overall power consumption. As well as being adaptable to input power from 100 - 240 VAC.

The analogy I would use is that I am not required to use single-weight non-detergent oil, paper oil filters (if any at all) and non-resistor plugs in a vintage automobile. Nor am I required to use gutta-percha gaskets or leather belts - that is if I actually wish to drive it.

Peter Wieck
Melrose Park, PA

On Thursday, 12 October 2017 15:14:56 UTC+1, wrote:
On Thursday, October 12, 2017 at 9:15:11 AM UTC-4, tabby wrote:

That seems confused. I was talking about the ballasts, which obviously do not need replacing. The tubes you refer to are hardly likely to be original, and even if they are replacing them won't save any power or money. All the OP needs is a 2 pole switch or relay.


It is the ballasts that drive the consumables. Magnetic ballasts of that vintage cannot handle T8 or T5 lamps, some cannot even handle high-efficiency T12 lamps. They also require manual-start switch systems which further degrades the lamps. They also consume considerable power in their own right.

A "smart" electronic ballast will adapt to various lamp options, consumes 30% less power, and will very nearly triple the longevity of the lamps and halve the overall power consumption. As well as being adaptable to input power from 100 - 240 VAC.

The analogy I would use is that I am not required to use single-weight non-detergent oil, paper oil filters (if any at all) and non-resistor plugs in a vintage automobile. Nor am I required to use gutta-percha gaskets or leather belts - that is if I actually wish to drive it.

Peter Wieck
Melrose Park, PA

US fluorescent lighting is different to UK in many ways. All our historic switchstart ballasts work fine with T12, T8 and a lot of LED tubes.


NT

On Thursday, October 12, 2017 at 1:26:37 PM UTC-4, wrote:

US fluorescent lighting is different to UK in many ways. All our historic switchstart ballasts work fine with T12, T8 and a lot of LED tubes.


That would explain a lot of your attitude. But, your electrical power is, on average, 50% more costly than power in the US - one would think that energy efficiency would would be of greater concern to you than it seems to be. We operate a 464 square meter center-hall colonial built in 1890 for US$239/month (180 GBP). And we heat in the winter and cool in the summer. This includes heat, hot water, electricity, cooking, drying, and municipal water and sewer. Yes, we use a clothes line in the summer. But energy is dirt-cheap in the US relative to the rest of the world - not to suggest we waste it, but the only incandescent lamps we own are in the chandeliers. They too, are slowly giving way to LEDs.

Peter Wieck
Melrose Park, PA

On Thursday, 12 October 2017 18:57:39 UTC+1, wrote:
On Thursday, October 12, 2017 at 1:26:37 PM UTC-4, tabby wrote:

US fluorescent lighting is different to UK in many ways. All our historic switchstart ballasts work fine with T12, T8 and a lot of LED tubes.


That would explain a lot of your attitude. But, your electrical power is, on average, 50% more costly than power in the US - one would think that energy efficiency would would be of greater concern to you than it seems to be. We operate a 464 square meter center-hall colonial built in 1890 for US$239/month (180 GBP). And we heat in the winter and cool in the summer. This includes heat, hot water, electricity, cooking, drying, and municipal water and sewer. Yes, we use a clothes line in the summer. But energy is dirt-cheap in the US relative to the rest of the world - not to suggest we waste it, but the only incandescent lamps we own are in the chandeliers. They too, are slowly giving way to LEDs.

Peter Wieck
Melrose Park, PA

At the risk of stating the obvious, a person that buys an ancient piece of lighting isn't looking for the peak possible energy efficiency. It already has linear fluorescent lights so is quite efficient anyway. Iron ballasts on a small low power light only used some of the time consume a trivial amount.

If the OP were desperate to save another £1 a year for some reason he could always fit LED tubes with a wire fitted to short the ballasts. I can't see any compelling reason to though.


NT

Yabbut...

I take the Senator Everett McKinley Dirksen attitude: A billion here, a billion there, pretty soon it is real money!

We actually had honorable politicians mores-so-than-not back in the day. Sure, they still screwed by the numbers and stole what they could - but they also took their jobs fairly seriously. And it was DDE that created the term "Military Industrial Complex", and as a warning, not a description.

An honest politician is one who, when he is bought, will stay bought.

Simon Cameron
US financier & politician (1799 - 1889)

Peter Wieck
Melrose Park PA

|schreef in bericht
...
|
|I have this old fluorescent desk lamp from the 60s at the latest that I'm
fixing. It weighs a ton, has been passed down from my father-in-law, and it
just retro-|cool. According to him it's always worked, except the F15-T8
bulbs are possibly original and very worn out, and only one bulb ever
lights. I've been told this |has always been a problem, and holding the
start button for a long time will sometimes get both to start. I've never
been successful but I don't like this and |want to fix it.
|
|Upon reverse engineering it I come up with this schematic (it's rough,
drawn in Paint!):
|
|
|https://imgur.com/a/0YYKV
|
|I'm no fluorescent light expert, but how the start button is connected to
both lamps seems odd to me, a little like directly paralleling LEDs or neon
bulbs after |the limit resistor. If I disconnect one bulb, the remaining
always starts. I doubt this design would ever work very well....would it?
|
|If I manually start each light by disconnecting the start button wires and
momentarily shorting the two pins at opposite ends of each lamp, they each
start |right up. My plan is to modify it with a DPDT relay with 120VAC coil
so the start button drives the coil, and each lamp has it's own set of relay
contacts. I'm |sure this will work, but.....WTF with the original design?
Is this normal? I doubt it's even been modified, and see no good way to fix
it without adding a relay |or a multipole start switch.
|
|I'm a little surprised to see some that seems this hokey (to me) in
something this old.

In a similar case, replacing the startbutton worked for me. Still don't know
how or why. (A little frustrating.)

Otherwise, seperate both lamps + ballasts and use two startbuttons.

petrus bitbyter

I have a funny feeling somebody used the wrong switch. I believe what you do manually, is what the switch does.

So, replace the switch with one designed to turn on a florescent light.

The desk lamp I have with that starting system is a single tube. Eons ago, the bas got painted and a new switch installed.

See http://www.edisontechcenter.org/Fluorescent.html for operation.

Here's another place to look. http://www.egaynor.com/edwin_gaynor_lampholders/666.htm These use two ballasts for a two bulb system.