Explain the output of the old TV flyback transformers....

[Lamont Cranston]

I\'m backing off of the neon sign transformer 12kV power supply. For the reasons I was told, the low frequency requires big capacitors. Also, I ordered 20kV caps from Amazon and 6 of the 12 failed at under 4kV. I should have read the reviews, it is well shown these fail.
So, I want a continuous DC voltage, I can imagine the old tripler design gave a decent continuous DC, but I\'m looking at this and wondering what kind of DC they have. https://www.ebay.com/itm/185000537079?var=692782023047
I don\'t see a tripler, I don\'t see any diodes or filter caps, I\'m hesitant to spend the fifty bucks to find it isn\'t what I need.
Any thoughts about this?
Thanks, Mikek

 

[John Larkin]

On Tue, 13 Jun 2023 09:22:20 -0700 (PDT), Lamont Cranston
<amdx62@gmail.com> wrote:

I\'m backing off of the neon sign transformer 12kV power supply. For the reasons I was told, the low frequency requires big capacitors. Also, I ordered 20kV caps from Amazon and 6 of the 12 failed at under 4kV. I should have read the reviews, it is well shown these fail.
So, I want a continuous DC voltage, I can imagine the old tripler design gave a decent continuous DC, but I\'m looking at this and wondering what kind of DC they have. https://www.ebay.com/itm/185000537079?var=692782023047
I don\'t see a tripler, I don\'t see any diodes or filter caps, I\'m hesitant to spend the fifty bucks to find it isn\'t what I need.
Any thoughts about this?
Thanks, Mikek

Some color TVs had a potted flyback-rectifier thing.

https://www.ebay.com/itm/266268712401?hash=item3dfeda1dd1:g:ZjUAAOSwMtJjVfKj&amdata=enc%3AAQAIAAAA4FkSVq2pZQAQFQ3H12RU5oBxz034DQjMgNb0SpovprqoAC9lmUILzo7UQOD6mORpnWwDWDkzPWIUtDhR40PoeddhTnTcHOIMviQ7J%2B4TKb4EENkJXKDXyP5N99Q5SDpcmLbn%2B52pNUnNG7D9wMmK8DJG1Ipa2UaBiWpAlOGLbl80axK%2BKmL9Cua77cwAJmfwF39%2FXC%2BP4BUGfJCc6I2ejKGqduU1xpDuLmVnOmw05c9rl8Rj6JOH2YLiOv%2BedgBO2I5zzWYjSwZKdXGomfJo1hNa6CQHPd22X9mybYVrJ2%2Bk%7Ctkp%3ABFBM1ICr25Zi

 

[Lamont Cranston]

On Tuesday, June 13, 2023 at 12:04:38 PM UTC-5, John Larkin wrote:

On Tue, 13 Jun 2023 09:22:20 -0700 (PDT), Lamont Cranston
amd...@gmail.com> wrote:

I\'m backing off of the neon sign transformer 12kV power supply. For the reasons I was told, the low frequency requires big capacitors. Also, I ordered 20kV caps from Amazon and 6 of the 12 failed at under 4kV. I should have read the reviews, it is well shown these fail.
So, I want a continuous DC voltage, I can imagine the old tripler design gave a decent continuous DC, but I\'m looking at this and wondering what kind of DC they have. https://www.ebay.com/itm/185000537079?var=692782023047
I don\'t see a tripler, I don\'t see any diodes or filter caps, I\'m hesitant to spend the fifty bucks to find it isn\'t what I need.
Any thoughts about this?
Thanks, Mikek
Some color TVs had a potted flyback-rectifier thing.

https://www.ebay.com/itm/266268712401?hash=item3dfeda1dd1:g:ZjUAAOSwMtJjVfKj&amdata=enc%3AAQAIAAAA4FkSVq2pZQAQFQ3H12RU5oBxz034DQjMgNb0SpovprqoAC9lmUILzo7UQOD6mORpnWwDWDkzPWIUtDhR40PoeddhTnTcHOIMviQ7J%2B4TKb4EENkJXKDXyP5N99Q5SDpcmLbn%2B52pNUnNG7D9wMmK8DJG1Ipa2UaBiWpAlOGLbl80axK%2BKmL9Cua77cwAJmfwF39%2FXC%2BP4BUGfJCc6I2ejKGqduU1xpDuLmVnOmw05c9rl8Rj6JOH2YLiOv%2BedgBO2I5zzWYjSwZKdXGomfJo1hNa6CQHPd22X9mybYVrJ2%2Bk%7Ctkp%3ABFBM1ICr25Zi

Any idea what the duty cycle of the input was on the TV flybacks?
Mikek

 

[Tauno Voipio]

On 13.6.2023 20.57, Lamont Cranston wrote:

On Tuesday, June 13, 2023 at 12:04:38 PM UTC-5, John Larkin wrote:
On Tue, 13 Jun 2023 09:22:20 -0700 (PDT), Lamont Cranston
amd...@gmail.com> wrote:

I\'m backing off of the neon sign transformer 12kV power supply. For the reasons I was told, the low frequency requires big capacitors. Also, I ordered 20kV caps from Amazon and 6 of the 12 failed at under 4kV. I should have read the reviews, it is well shown these fail.
So, I want a continuous DC voltage, I can imagine the old tripler design gave a decent continuous DC, but I\'m looking at this and wondering what kind of DC they have. https://www.ebay.com/itm/185000537079?var=692782023047
I don\'t see a tripler, I don\'t see any diodes or filter caps, I\'m hesitant to spend the fifty bucks to find it isn\'t what I need.
Any thoughts about this?
Thanks, Mikek
Some color TVs had a potted flyback-rectifier thing.

https://www.ebay.com/itm/266268712401?hash=item3dfeda1dd1:g:ZjUAAOSwMtJjVfKj&amdata=enc%3AAQAIAAAA4FkSVq2pZQAQFQ3H12RU5oBxz034DQjMgNb0SpovprqoAC9lmUILzo7UQOD6mORpnWwDWDkzPWIUtDhR40PoeddhTnTcHOIMviQ7J%2B4TKb4EENkJXKDXyP5N99Q5SDpcmLbn%2B52pNUnNG7D9wMmK8DJG1Ipa2UaBiWpAlOGLbl80axK%2BKmL9Cua77cwAJmfwF39%2FXC%2BP4BUGfJCc6I2ejKGqduU1xpDuLmVnOmw05c9rl8Rj6JOH2YLiOv%2BedgBO2I5zzWYjSwZKdXGomfJo1hNa6CQHPd22X9mybYVrJ2%2Bk%7Ctkp%3ABFBM1ICr25Zi

Any idea what the duty cycle of the input was on the TV flybacks?
Mikek

For CCIR type G analog raster (625 line, 50 half-frames / second), the
trace time was about 53 us and retrace 11 us, for a sum of 64 us.

--

-TV

 

[Lamont Cranston]

On Tuesday, June 13, 2023 at 1:38:10 PM UTC-5, Tauno Voipio wrote:

On 13.6.2023 20.57, Lamont Cranston wrote:
On Tuesday, June 13, 2023 at 12:04:38 PM UTC-5, John Larkin wrote:
On Tue, 13 Jun 2023 09:22:20 -0700 (PDT), Lamont Cranston
amd...@gmail.com> wrote:

I\'m backing off of the neon sign transformer 12kV power supply. For the reasons I was told, the low frequency requires big capacitors. Also, I ordered 20kV caps from Amazon and 6 of the 12 failed at under 4kV. I should have read the reviews, it is well shown these fail.
So, I want a continuous DC voltage, I can imagine the old tripler design gave a decent continuous DC, but I\'m looking at this and wondering what kind of DC they have. https://www.ebay.com/itm/185000537079?var=692782023047
I don\'t see a tripler, I don\'t see any diodes or filter caps, I\'m hesitant to spend the fifty bucks to find it isn\'t what I need.
Any thoughts about this?
Thanks, Mikek
Some color TVs had a potted flyback-rectifier thing.

https://www.ebay.com/itm/266268712401?hash=item3dfeda1dd1:g:ZjUAAOSwMtJjVfKj&amdata=enc%3AAQAIAAAA4FkSVq2pZQAQFQ3H12RU5oBxz034DQjMgNb0SpovprqoAC9lmUILzo7UQOD6mORpnWwDWDkzPWIUtDhR40PoeddhTnTcHOIMviQ7J%2B4TKb4EENkJXKDXyP5N99Q5SDpcmLbn%2B52pNUnNG7D9wMmK8DJG1Ipa2UaBiWpAlOGLbl80axK%2BKmL9Cua77cwAJmfwF39%2FXC%2BP4BUGfJCc6I2ejKGqduU1xpDuLmVnOmw05c9rl8Rj6JOH2YLiOv%2BedgBO2I5zzWYjSwZKdXGomfJo1hNa6CQHPd22X9mybYVrJ2%2Bk%7Ctkp%3ABFBM1ICr25Zi

Any idea what the duty cycle of the input was on the TV flybacks?
Mikek
For CCIR type G analog raster (625 line, 50 half-frames / second), the
trace time was about 53 us and retrace 11 us, for a sum of 64 us.

--

-TV

I have a couple of defective High frequency switching type neon sign power supplies.
Neither work and seem to have open secondaries. I removed the switching pcb and found
defective IRF 630 FETs, I replaced them and got it switching, but no HV. So, of course I stuck
the transformer in the barbecue and melted off all the tar, and a little kerosene and it was free.
https://www.dropbox.com/s/xsc1f0edqc0w3jk/Neon%20switching%20supply%20transformer%202.jpg?dl=0
But, I was surprised to see a pcb encased in the tar, that connects the two secondary windings
at the CT. It has a 555 a couple of SCRs and caps a diodes to make a power supply for the 555.
I\'m not sure of the purpose of this pcb, it would seem like current limiting, but this runs at 21kHz,
I would think secondary impedance would be enough to limit current.
Any thought as to what the pcb connecting the two secondary windings together would be doing?
https://www.dropbox.com/s/4c4he4esxxtjn7y/Neon%20switching%20supply%20CT%20pcb.jpg?dl=0
Mikek

 

[John Robertson]

On 2023/06/13 9:22 a.m., Lamont Cranston wrote:

I\'m backing off of the neon sign transformer 12kV power supply. For the reasons I was told, the low frequency requires big capacitors. Also, I ordered 20kV caps from Amazon and 6 of the 12 failed at under 4kV. I should have read the reviews, it is well shown these fail.
So, I want a continuous DC voltage, I can imagine the old tripler design gave a decent continuous DC, but I\'m looking at this and wondering what kind of DC they have. https://www.ebay.com/itm/185000537079?var=692782023047
I don\'t see a tripler, I don\'t see any diodes or filter caps, I\'m hesitant to spend the fifty bucks to find it isn\'t what I need.
Any thoughts about this?
Thanks, Mikek

What sort of HV are you after and what are the current requirements?

A Neon sign transformer will give you milliamps at the rated output
voltage which could be deadly if misapplied...

The HV from a TV won\'t kill you, it just gives you one heck of a jolt!

You may want to just use an old B&W or colour TV that you pick up at a
thrift shop and use that as your HV source.

It all depends on your application.

John :-#)#
--
(Please post followups or tech inquiries to the USENET newsgroup)
John\'s Jukes Ltd.
#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.\"

 

[Lamont Cranston]

On Tuesday, June 13, 2023 at 7:49:53 PM UTC-5, John Robertson wrote:

On 2023/06/13 9:22 a.m., Lamont Cranston wrote:
I\'m backing off of the neon sign transformer 12kV power supply. For the reasons I was told, the low frequency requires big capacitors. Also, I ordered 20kV caps from Amazon and 6 of the 12 failed at under 4kV. I should have read the reviews, it is well shown these fail.
So, I want a continuous DC voltage, I can imagine the old tripler design gave a decent continuous DC, but I\'m looking at this and wondering what kind of DC they have. https://www.ebay.com/itm/185000537079?var=692782023047
I don\'t see a tripler, I don\'t see any diodes or filter caps, I\'m hesitant to spend the fifty bucks to find it isn\'t what I need.
Any thoughts about this?
Thanks, Mikek

What sort of HV are you after and what are the current requirements?

A Neon sign transformer will give you milliamps at the rated output
voltage which could be deadly if misapplied...

The HV from a TV won\'t kill you, it just gives you one heck of a jolt!

You may want to just use an old B&W or colour TV that you pick up at a
thrift shop and use that as your HV source.

It all depends on your application.

Please see \"Developing High Voltage pulses\" June 5.
I have a functioning Pulser, but need a 12kV power source that will provide 2ma of current.
btw, do still see old CRT TVs at thrift stores?
Thanks, Mikek

 

[Tabby]

On Tuesday, 13 June 2023 at 17:22:25 UTC+1, Lamont Cranston wrote:

I\'m backing off of the neon sign transformer 12kV power supply. For the reasons I was told, the low frequency requires big capacitors. Also, I ordered 20kV caps from Amazon and 6 of the 12 failed at under 4kV. I should have read the reviews, it is well shown these fail.
So, I want a continuous DC voltage, I can imagine the old tripler design gave a decent continuous DC, but I\'m looking at this and wondering what kind of DC they have. https://www.ebay.com/itm/185000537079?var=692782023047
I don\'t see a tripler, I don\'t see any diodes or filter caps, I\'m hesitant to spend the fifty bucks to find it isn\'t what I need.
Any thoughts about this?
Thanks, Mikek

100w is unlikely. If true it\'s lethal. If untrue, the voltage is also unlikely to be true.
Output is either ac or rectified dc. Roll your own cap if you want nice dc, or buy an old doorknob cap that\'s tested good.

 

[Lamont Cranston]

On Wednesday, June 14, 2023 at 5:09:03 PM UTC-5, Tabby wrote:

On Tuesday, 13 June 2023 at 17:22:25 UTC+1, Lamont Cranston wrote:
I\'m backing off of the neon sign transformer 12kV power supply. For the reasons I was told, the low frequency requires big capacitors. Also, I ordered 20kV caps from Amazon and 6 of the 12 failed at under 4kV. I should have read the reviews, it is well shown these fail.
So, I want a continuous DC voltage, I can imagine the old tripler design gave a decent continuous DC, but I\'m looking at this and wondering what kind of DC they have. https://www.ebay.com/itm/185000537079?var=692782023047
I don\'t see a tripler, I don\'t see any diodes or filter caps, I\'m hesitant to spend the fifty bucks to find it isn\'t what I need.
Any thoughts about this?
Thanks, Mikek

100w is unlikely. If true it\'s lethal. If untrue, the voltage is also unlikely to be true.
Output is either ac or rectified dc. Roll your own cap if you want nice dc, or buy an old doorknob cap that\'s tested good.

I sent a question about the output to the seller, they forwarded it on to the manufacturer.

 

[John Robertson]

On 2023/06/13 8:06 p.m., Lamont Cranston wrote:

On Tuesday, June 13, 2023 at 7:49:53 PM UTC-5, John Robertson wrote:
On 2023/06/13 9:22 a.m., Lamont Cranston wrote:
I\'m backing off of the neon sign transformer 12kV power supply. For the reasons I was told, the low frequency requires big capacitors. Also, I ordered 20kV caps from Amazon and 6 of the 12 failed at under 4kV. I should have read the reviews, it is well shown these fail.
So, I want a continuous DC voltage, I can imagine the old tripler design gave a decent continuous DC, but I\'m looking at this and wondering what kind of DC they have. https://www.ebay.com/itm/185000537079?var=692782023047
I don\'t see a tripler, I don\'t see any diodes or filter caps, I\'m hesitant to spend the fifty bucks to find it isn\'t what I need.
Any thoughts about this?
Thanks, Mikek

What sort of HV are you after and what are the current requirements?

A Neon sign transformer will give you milliamps at the rated output
voltage which could be deadly if misapplied...

The HV from a TV won\'t kill you, it just gives you one heck of a jolt!

You may want to just use an old B&W or colour TV that you pick up at a
thrift shop and use that as your HV source.

It all depends on your application.

Please see \"Developing High Voltage pulses\" June 5.
I have a functioning Pulser, but need a 12kV power source that will provide 2ma of current.
btw, do still see old CRT TVs at thrift stores?
Thanks, Mikek

I have a pile of monitors here and flybacks as we service old arcade
game monitors. You need 200ma at 120VDC if the flyback is lossless.
Might be able to do that. You can use a B&W flyback as they tend to be
running around 12KV and the primary side is pulsed 73VDC or so. 19\"
colour monitors flybacks run around 15 to 20KV at a B+ of 120VDC pulsed.
Lower B+ would give lower output voltage of course.

A common flyback is the GO7 Electrohome which runs at 15,xxx Khz and has
built in HV diodes. I sell these here:

https://flippers.com/catalog_oc/go7-electrohome-flyback-replacement-a-29951b

You could use a picture tube as a smoothing filter cap I imagine...

John :-#)#
--
(Please post followups or tech inquiries to the USENET newsgroup)
John\'s Jukes Ltd.
#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.\"

 

[John Walliker]

On Thursday, 15 June 2023 at 07:41:43 UTC+1, John Robertson wrote:

On 2023/06/13 8:06 p.m., Lamont Cranston wrote:
On Tuesday, June 13, 2023 at 7:49:53 PM UTC-5, John Robertson wrote:
On 2023/06/13 9:22 a.m., Lamont Cranston wrote:
I\'m backing off of the neon sign transformer 12kV power supply. For the reasons I was told, the low frequency requires big capacitors. Also, I ordered 20kV caps from Amazon and 6 of the 12 failed at under 4kV. I should have read the reviews, it is well shown these fail.
So, I want a continuous DC voltage, I can imagine the old tripler design gave a decent continuous DC, but I\'m looking at this and wondering what kind of DC they have. https://www.ebay.com/itm/185000537079?var=692782023047
I don\'t see a tripler, I don\'t see any diodes or filter caps, I\'m hesitant to spend the fifty bucks to find it isn\'t what I need.
Any thoughts about this?
Thanks, Mikek

What sort of HV are you after and what are the current requirements?

A Neon sign transformer will give you milliamps at the rated output
voltage which could be deadly if misapplied...

The HV from a TV won\'t kill you, it just gives you one heck of a jolt!

You may want to just use an old B&W or colour TV that you pick up at a
thrift shop and use that as your HV source.

It all depends on your application.

Please see \"Developing High Voltage pulses\" June 5.
I have a functioning Pulser, but need a 12kV power source that will provide 2ma of current.
btw, do still see old CRT TVs at thrift stores?
Thanks, Mikek
I have a pile of monitors here and flybacks as we service old arcade
game monitors. You need 200ma at 120VDC if the flyback is lossless.
Might be able to do that. You can use a B&W flyback as they tend to be
running around 12KV and the primary side is pulsed 73VDC or so. 19\"
colour monitors flybacks run around 15 to 20KV at a B+ of 120VDC pulsed.
Lower B+ would give lower output voltage of course.

A common flyback is the GO7 Electrohome which runs at 15,xxx Khz and has
built in HV diodes. I sell these here:

https://flippers.com/catalog_oc/go7-electrohome-flyback-replacement-a-29951b

You could use a picture tube as a smoothing filter cap I imagine...
John :-#)#

.... or alternating sheets of an insulator such as glass or teflon sheet and aluminium
foil.
John

 

[Tabby]

On Thursday, 15 June 2023 at 00:10:47 UTC+1, Lamont Cranston wrote:

On Wednesday, June 14, 2023 at 5:09:03 PM UTC-5, Tabby wrote:
On Tuesday, 13 June 2023 at 17:22:25 UTC+1, Lamont Cranston wrote:
I\'m backing off of the neon sign transformer 12kV power supply. For the reasons I was told, the low frequency requires big capacitors. Also, I ordered 20kV caps from Amazon and 6 of the 12 failed at under 4kV. I should have read the reviews, it is well shown these fail.
So, I want a continuous DC voltage, I can imagine the old tripler design gave a decent continuous DC, but I\'m looking at this and wondering what kind of DC they have. https://www.ebay.com/itm/185000537079?var=692782023047
I don\'t see a tripler, I don\'t see any diodes or filter caps, I\'m hesitant to spend the fifty bucks to find it isn\'t what I need.
Any thoughts about this?
Thanks, Mikek

100w is unlikely. If true it\'s lethal. If untrue, the voltage is also unlikely to be true.
Output is either ac or rectified dc. Roll your own cap if you want nice dc, or buy an old doorknob cap that\'s tested good.
I sent a question about the output to the seller, they forwarded it on to the manufacturer.

totally pointless

 

[Lamont Cranston]

On Thursday, June 15, 2023 at 3:32:29 PM UTC-5, Tabby wrote:

I sent a question about the output to the seller, they forwarded it on to the manufacturer.
totally pointless

What is pointless? Asking for more info, or expecting to get it?
Mikek

 

[Tabby]

On Thursday, 15 June 2023 at 07:41:43 UTC+1, John Robertson wrote:

On 2023/06/13 8:06 p.m., Lamont Cranston wrote:
On Tuesday, June 13, 2023 at 7:49:53 PM UTC-5, John Robertson wrote:
On 2023/06/13 9:22 a.m., Lamont Cranston wrote:
I\'m backing off of the neon sign transformer 12kV power supply. For the reasons I was told, the low frequency requires big capacitors. Also, I ordered 20kV caps from Amazon and 6 of the 12 failed at under 4kV. I should have read the reviews, it is well shown these fail.
So, I want a continuous DC voltage, I can imagine the old tripler design gave a decent continuous DC, but I\'m looking at this and wondering what kind of DC they have. https://www.ebay.com/itm/185000537079?var=692782023047
I don\'t see a tripler, I don\'t see any diodes or filter caps, I\'m hesitant to spend the fifty bucks to find it isn\'t what I need.
Any thoughts about this?
Thanks, Mikek

What sort of HV are you after and what are the current requirements?

A Neon sign transformer will give you milliamps at the rated output
voltage which could be deadly if misapplied...

The HV from a TV won\'t kill you, it just gives you one heck of a jolt!

You may want to just use an old B&W or colour TV that you pick up at a
thrift shop and use that as your HV source.

It all depends on your application.

Please see \"Developing High Voltage pulses\" June 5.
I have a functioning Pulser, but need a 12kV power source that will provide 2ma of current.
btw, do still see old CRT TVs at thrift stores?
Thanks, Mikek
I have a pile of monitors here and flybacks as we service old arcade
game monitors. You need 200ma at 120VDC if the flyback is lossless.
Might be able to do that. You can use a B&W flyback as they tend to be
running around 12KV and the primary side is pulsed 73VDC or so. 19\"
colour monitors flybacks run around 15 to 20KV at a B+ of 120VDC pulsed.
Lower B+ would give lower output voltage of course.

A common flyback is the GO7 Electrohome which runs at 15,xxx Khz and has
built in HV diodes. I sell these here:

https://flippers.com/catalog_oc/go7-electrohome-flyback-replacement-a-29951b

You could use a picture tube as a smoothing filter cap I imagine...
John :-#)#

or pick up a scrap crt tv
Cap can use glass sheets or jars, or wax soaked card. Test it to at least double run voltage - or that of course you need a cap.

 

[Lamont Cranston]

On Tuesday, June 13, 2023 at 7:40:39 PM UTC-5, Lamont Cranston wrote:

On Tuesday, June 13, 2023 at 1:38:10 PM UTC-5, Tauno Voipio wrote:
On 13.6.2023 20.57, Lamont Cranston wrote:
On Tuesday, June 13, 2023 at 12:04:38 PM UTC-5, John Larkin wrote:
On Tue, 13 Jun 2023 09:22:20 -0700 (PDT), Lamont Cranston
amd...@gmail.com> wrote:

I\'m backing off of the neon sign transformer 12kV power supply. For the reasons I was told, the low frequency requires big capacitors. Also, I ordered 20kV caps from Amazon and 6 of the 12 failed at under 4kV. I should have read the reviews, it is well shown these fail.
So, I want a continuous DC voltage, I can imagine the old tripler design gave a decent continuous DC, but I\'m looking at this and wondering what kind of DC they have. https://www.ebay.com/itm/185000537079?var=692782023047
I don\'t see a tripler, I don\'t see any diodes or filter caps, I\'m hesitant to spend the fifty bucks to find it isn\'t what I need.
Any thoughts about this?
Thanks, Mikek
Some color TVs had a potted flyback-rectifier thing.

https://www.ebay.com/itm/266268712401?hash=item3dfeda1dd1:g:ZjUAAOSwMtJjVfKj&amdata=enc%3AAQAIAAAA4FkSVq2pZQAQFQ3H12RU5oBxz034DQjMgNb0SpovprqoAC9lmUILzo7UQOD6mORpnWwDWDkzPWIUtDhR40PoeddhTnTcHOIMviQ7J%2B4TKb4EENkJXKDXyP5N99Q5SDpcmLbn%2B52pNUnNG7D9wMmK8DJG1Ipa2UaBiWpAlOGLbl80axK%2BKmL9Cua77cwAJmfwF39%2FXC%2BP4BUGfJCc6I2ejKGqduU1xpDuLmVnOmw05c9rl8Rj6JOH2YLiOv%2BedgBO2I5zzWYjSwZKdXGomfJo1hNa6CQHPd22X9mybYVrJ2%2Bk%7Ctkp%3ABFBM1ICr25Zi

Any idea what the duty cycle of the input was on the TV flybacks?
Mikek
For CCIR type G analog raster (625 line, 50 half-frames / second), the
trace time was about 53 us and retrace 11 us, for a sum of 64 us.

--

-TV
I have a couple of defective High frequency switching type neon sign power supplies.
Neither work and seem to have open secondaries. I removed the switching pcb and found
defective IRF 630 FETs, I replaced them and got it switching, but no HV. So, of course I stuck
the transformer in the barbecue and melted off all the tar, and a little kerosene and it was free.
https://www.dropbox.com/s/xsc1f0edqc0w3jk/Neon%20switching%20supply%20transformer%202.jpg?dl=0
But, I was surprised to see a pcb encased in the tar, that connects the two secondary windings
at the CT. It has a 555 a couple of SCRs and caps a diodes to make a power supply for the 555.
I\'m not sure of the purpose of this pcb, it would seem like current limiting, but this runs at 21kHz,
I would think secondary impedance would be enough to limit current.
Any thought as to what the pcb connecting the two secondary windings together would be doing?
https://www.dropbox.com/s/4c4he4esxxtjn7y/Neon%20switching%20supply%20CT%20pcb.jpg?dl=0
Mikek

I drew the schematic of the tar potted pcb that is connected between the two halves of the secondary. I\'d like opinions on what the function
of the pcb is. It has a 555 driving two SCRs. The transformer already has a driver circuit on the primary.
What is the function of this circuit on the secondary.

https://www.dropbox.com/s/jkl62gxr6omhxib/Switching%20Power%20Supply%20CT%20%20PCB.jpg?dl=0

Picture of pcb,
https://www.dropbox.com/s/4c4he4esxxtjn7y/Neon%20switching%20supply%20CT%20pcb.jpg?dl=0
Thanks, Mikek

 

[Lamont Cranston]

On Saturday, June 17, 2023 at 1:04:33 AM UTC-5, Lamont Cranston wrote:

On Tuesday, June 13, 2023 at 7:40:39 PM UTC-5, Lamont Cranston wrote:
On Tuesday, June 13, 2023 at 1:38:10 PM UTC-5, Tauno Voipio wrote:
On 13.6.2023 20.57, Lamont Cranston wrote:
On Tuesday, June 13, 2023 at 12:04:38 PM UTC-5, John Larkin wrote:
On Tue, 13 Jun 2023 09:22:20 -0700 (PDT), Lamont Cranston
amd...@gmail.com> wrote:

I\'m backing off of the neon sign transformer 12kV power supply. For the reasons I was told, the low frequency requires big capacitors. Also, I ordered 20kV caps from Amazon and 6 of the 12 failed at under 4kV. I should have read the reviews, it is well shown these fail.
So, I want a continuous DC voltage, I can imagine the old tripler design gave a decent continuous DC, but I\'m looking at this and wondering what kind of DC they have. https://www.ebay.com/itm/185000537079?var=692782023047
I don\'t see a tripler, I don\'t see any diodes or filter caps, I\'m hesitant to spend the fifty bucks to find it isn\'t what I need.
Any thoughts about this?
Thanks, Mikek
Some color TVs had a potted flyback-rectifier thing.

https://www.ebay.com/itm/266268712401?hash=item3dfeda1dd1:g:ZjUAAOSwMtJjVfKj&amdata=enc%3AAQAIAAAA4FkSVq2pZQAQFQ3H12RU5oBxz034DQjMgNb0SpovprqoAC9lmUILzo7UQOD6mORpnWwDWDkzPWIUtDhR40PoeddhTnTcHOIMviQ7J%2B4TKb4EENkJXKDXyP5N99Q5SDpcmLbn%2B52pNUnNG7D9wMmK8DJG1Ipa2UaBiWpAlOGLbl80axK%2BKmL9Cua77cwAJmfwF39%2FXC%2BP4BUGfJCc6I2ejKGqduU1xpDuLmVnOmw05c9rl8Rj6JOH2YLiOv%2BedgBO2I5zzWYjSwZKdXGomfJo1hNa6CQHPd22X9mybYVrJ2%2Bk%7Ctkp%3ABFBM1ICr25Zi

Any idea what the duty cycle of the input was on the TV flybacks?
Mikek
For CCIR type G analog raster (625 line, 50 half-frames / second), the
trace time was about 53 us and retrace 11 us, for a sum of 64 us.

--

-TV
I have a couple of defective High frequency switching type neon sign power supplies.
Neither work and seem to have open secondaries. I removed the switching pcb and found
defective IRF 630 FETs, I replaced them and got it switching, but no HV.. So, of course I stuck
the transformer in the barbecue and melted off all the tar, and a little kerosene and it was free.
https://www.dropbox.com/s/xsc1f0edqc0w3jk/Neon%20switching%20supply%20transformer%202.jpg?dl=0
But, I was surprised to see a pcb encased in the tar, that connects the two secondary windings
at the CT. It has a 555 a couple of SCRs and caps a diodes to make a power supply for the 555.
I\'m not sure of the purpose of this pcb, it would seem like current limiting, but this runs at 21kHz,
I would think secondary impedance would be enough to limit current.
Any thought as to what the pcb connecting the two secondary windings together would be doing?
https://www.dropbox.com/s/4c4he4esxxtjn7y/Neon%20switching%20supply%20CT%20pcb.jpg?dl=0
Mikek
I drew the schematic of the tar potted pcb that is connected between the two halves of the secondary. I\'d like opinions on what the function
of the pcb is. It has a 555 driving two SCRs. The transformer already has a driver circuit on the primary.
What is the function of this circuit on the secondary.

https://www.dropbox.com/s/jkl62gxr6omhxib/Switching%20Power%20Supply%20CT%20%20PCB.jpg?dl=0

Picture of pcb,
https://www.dropbox.com/s/4c4he4esxxtjn7y/Neon%20switching%20supply%20CT%20pcb.jpg?dl=0
Thanks, Mikek

Has this Center Tap circuit stumped everyone?
Mikek

 

[Anthony William Sloman]

On Monday, June 19, 2023 at 12:56:10 AM UTC+10, Lamont Cranston wrote:

On Saturday, June 17, 2023 at 1:04:33 AM UTC-5, Lamont Cranston wrote:
On Tuesday, June 13, 2023 at 7:40:39 PM UTC-5, Lamont Cranston wrote:
On Tuesday, June 13, 2023 at 1:38:10 PM UTC-5, Tauno Voipio wrote:
On 13.6.2023 20.57, Lamont Cranston wrote:
On Tuesday, June 13, 2023 at 12:04:38 PM UTC-5, John Larkin wrote:
On Tue, 13 Jun 2023 09:22:20 -0700 (PDT), Lamont Cranston
amd...@gmail.com> wrote:

I\'m backing off of the neon sign transformer 12kV power supply. For the reasons I was told, the low frequency requires big capacitors. Also, I ordered 20kV caps from Amazon and 6 of the 12 failed at under 4kV. I should have read the reviews, it is well shown these fail.
So, I want a continuous DC voltage, I can imagine the old tripler design gave a decent continuous DC, but I\'m looking at this and wondering what kind of DC they have. https://www.ebay.com/itm/185000537079?var=692782023047
I don\'t see a tripler, I don\'t see any diodes or filter caps, I\'m hesitant to spend the fifty bucks to find it isn\'t what I need.
Any thoughts about this?
Thanks, Mikek
Some color TVs had a potted flyback-rectifier thing.

https://www.ebay.com/itm/266268712401?hash=item3dfeda1dd1:g:ZjUAAOSwMtJjVfKj&amdata=enc%3AAQAIAAAA4FkSVq2pZQAQFQ3H12RU5oBxz034DQjMgNb0SpovprqoAC9lmUILzo7UQOD6mORpnWwDWDkzPWIUtDhR40PoeddhTnTcHOIMviQ7J%2B4TKb4EENkJXKDXyP5N99Q5SDpcmLbn%2B52pNUnNG7D9wMmK8DJG1Ipa2UaBiWpAlOGLbl80axK%2BKmL9Cua77cwAJmfwF39%2FXC%2BP4BUGfJCc6I2ejKGqduU1xpDuLmVnOmw05c9rl8Rj6JOH2YLiOv%2BedgBO2I5zzWYjSwZKdXGomfJo1hNa6CQHPd22X9mybYVrJ2%2Bk%7Ctkp%3ABFBM1ICr25Zi

Any idea what the duty cycle of the input was on the TV flybacks?
Mikek
For CCIR type G analog raster (625 line, 50 half-frames / second), the
trace time was about 53 us and retrace 11 us, for a sum of 64 us.

--

-TV
I have a couple of defective High frequency switching type neon sign power supplies.
Neither work and seem to have open secondaries. I removed the switching pcb and found
defective IRF 630 FETs, I replaced them and got it switching, but no HV. So, of course I stuck
the transformer in the barbecue and melted off all the tar, and a little kerosene and it was free.
https://www.dropbox.com/s/xsc1f0edqc0w3jk/Neon%20switching%20supply%20transformer%202.jpg?dl=0
But, I was surprised to see a pcb encased in the tar, that connects the two secondary windings
at the CT. It has a 555 a couple of SCRs and caps a diodes to make a power supply for the 555.
I\'m not sure of the purpose of this pcb, it would seem like current limiting, but this runs at 21kHz,
I would think secondary impedance would be enough to limit current.
Any thought as to what the pcb connecting the two secondary windings together would be doing?
https://www.dropbox.com/s/4c4he4esxxtjn7y/Neon%20switching%20supply%20CT%20pcb.jpg?dl=0
Mikek
I drew the schematic of the tar potted pcb that is connected between the two halves of the secondary. I\'d like opinions on what the function
of the pcb is. It has a 555 driving two SCRs. The transformer already has a driver circuit on the primary.
What is the function of this circuit on the secondary.

https://www.dropbox.com/s/jkl62gxr6omhxib/Switching%20Power%20Supply%20CT%20%20PCB.jpg?dl=0

Picture of pcb,
https://www.dropbox.com/s/4c4he4esxxtjn7y/Neon%20switching%20supply%20CT%20pcb.jpg?dl=0

Has this Center Tap circuit stumped everyone?

More likely they can\'t be bothered redrawing it in a way that makes it easy to make sense of what it is doing. Since there\'s a 555 at the heart of it it\'s either old or designed by somebody who didn\'t notice when the 555 went obsolete - like John Fields. The fact that the winding direction of the two secondaries isn\'t specified - no dots - is bad start.

No turns ratios and no specification of the primary drive makes it difficult to work out what might be going on. I\'m not temped to try.

--
Bill Slonman, Sydney

 

[ehsjr]

On 6/18/2023 10:56 AM, Lamont Cranston wrote:

On Saturday, June 17, 2023 at 1:04:33 AM UTC-5, Lamont Cranston wrote:
On Tuesday, June 13, 2023 at 7:40:39 PM UTC-5, Lamont Cranston wrote:
On Tuesday, June 13, 2023 at 1:38:10 PM UTC-5, Tauno Voipio wrote:
On 13.6.2023 20.57, Lamont Cranston wrote:
On Tuesday, June 13, 2023 at 12:04:38 PM UTC-5, John Larkin wrote:
On Tue, 13 Jun 2023 09:22:20 -0700 (PDT), Lamont Cranston
amd...@gmail.com> wrote:

I\'m backing off of the neon sign transformer 12kV power supply. For the reasons I was told, the low frequency requires big capacitors. Also, I ordered 20kV caps from Amazon and 6 of the 12 failed at under 4kV. I should have read the reviews, it is well shown these fail.
So, I want a continuous DC voltage, I can imagine the old tripler design gave a decent continuous DC, but I\'m looking at this and wondering what kind of DC they have. https://www.ebay.com/itm/185000537079?var=692782023047
I don\'t see a tripler, I don\'t see any diodes or filter caps, I\'m hesitant to spend the fifty bucks to find it isn\'t what I need.
Any thoughts about this?
Thanks, Mikek
Some color TVs had a potted flyback-rectifier thing.

https://www.ebay.com/itm/266268712401?hash=item3dfeda1dd1:g:ZjUAAOSwMtJjVfKj&amdata=enc%3AAQAIAAAA4FkSVq2pZQAQFQ3H12RU5oBxz034DQjMgNb0SpovprqoAC9lmUILzo7UQOD6mORpnWwDWDkzPWIUtDhR40PoeddhTnTcHOIMviQ7J%2B4TKb4EENkJXKDXyP5N99Q5SDpcmLbn%2B52pNUnNG7D9wMmK8DJG1Ipa2UaBiWpAlOGLbl80axK%2BKmL9Cua77cwAJmfwF39%2FXC%2BP4BUGfJCc6I2ejKGqduU1xpDuLmVnOmw05c9rl8Rj6JOH2YLiOv%2BedgBO2I5zzWYjSwZKdXGomfJo1hNa6CQHPd22X9mybYVrJ2%2Bk%7Ctkp%3ABFBM1ICr25Zi

Any idea what the duty cycle of the input was on the TV flybacks?
Mikek
For CCIR type G analog raster (625 line, 50 half-frames / second), the
trace time was about 53 us and retrace 11 us, for a sum of 64 us.

--

-TV
I have a couple of defective High frequency switching type neon sign power supplies.
Neither work and seem to have open secondaries. I removed the switching pcb and found
defective IRF 630 FETs, I replaced them and got it switching, but no HV. So, of course I stuck
the transformer in the barbecue and melted off all the tar, and a little kerosene and it was free.
https://www.dropbox.com/s/xsc1f0edqc0w3jk/Neon%20switching%20supply%20transformer%202.jpg?dl=0
But, I was surprised to see a pcb encased in the tar, that connects the two secondary windings
at the CT. It has a 555 a couple of SCRs and caps a diodes to make a power supply for the 555.
I\'m not sure of the purpose of this pcb, it would seem like current limiting, but this runs at 21kHz,
I would think secondary impedance would be enough to limit current.
Any thought as to what the pcb connecting the two secondary windings together would be doing?
https://www.dropbox.com/s/4c4he4esxxtjn7y/Neon%20switching%20supply%20CT%20pcb.jpg?dl=0
Mikek
I drew the schematic of the tar potted pcb that is connected between the two halves of the secondary. I\'d like opinions on what the function
of the pcb is. It has a 555 driving two SCRs. The transformer already has a driver circuit on the primary.
What is the function of this circuit on the secondary.

https://www.dropbox.com/s/jkl62gxr6omhxib/Switching%20Power%20Supply%20CT%20%20PCB.jpg?dl=0

Picture of pcb,
https://www.dropbox.com/s/4c4he4esxxtjn7y/Neon%20switching%20supply%20CT%20pcb.jpg?dl=0
Thanks, Mikek

Has this Center Tap circuit stumped everyone?
Mikek

Are you sure those \"SCRs\" aren\'t triacs?
Ed

 

[Fred Bloggs]

On Tuesday, June 13, 2023 at 1:04:38 PM UTC-4, John Larkin wrote:

On Tue, 13 Jun 2023 09:22:20 -0700 (PDT), Lamont Cranston
amd...@gmail.com> wrote:

I\'m backing off of the neon sign transformer 12kV power supply. For the reasons I was told, the low frequency requires big capacitors. Also, I ordered 20kV caps from Amazon and 6 of the 12 failed at under 4kV. I should have read the reviews, it is well shown these fail.
So, I want a continuous DC voltage, I can imagine the old tripler design gave a decent continuous DC, but I\'m looking at this and wondering what kind of DC they have. https://www.ebay.com/itm/185000537079?var=692782023047
I don\'t see a tripler, I don\'t see any diodes or filter caps, I\'m hesitant to spend the fifty bucks to find it isn\'t what I need.
Any thoughts about this?
Thanks, Mikek
Some color TVs had a potted flyback-rectifier thing.

https://www.ebay.com/itm/266268712401?hash=item3dfeda1dd1:g:ZjUAAOSwMtJjVfKj&amdata=enc%3AAQAIAAAA4FkSVq2pZQAQFQ3H12RU5oBxz034DQjMgNb0SpovprqoAC9lmUILzo7UQOD6mORpnWwDWDkzPWIUtDhR40PoeddhTnTcHOIMviQ7J%2B4TKb4EENkJXKDXyP5N99Q5SDpcmLbn%2B52pNUnNG7D9wMmK8DJG1Ipa2UaBiWpAlOGLbl80axK%2BKmL9Cua77cwAJmfwF39%2FXC%2BP4BUGfJCc6I2ejKGqduU1xpDuLmVnOmw05c9rl8Rj6JOH2YLiOv%2BedgBO2I5zzWYjSwZKdXGomfJo1hNa6CQHPd22X9mybYVrJ2%2Bk%7Ctkp%3ABFBM1ICr25Zi

It\'s just a blocking oscillator modified for regulation.

 

[Lamont Cranston]

Has this Center Tap circuit stumped everyone?
Mikek
Are you sure those \"SCRs\" aren\'t triacs?
Ed

Not absolutely, but it looks like they are, the label is,
Motorola, 642 CR 106-6
Here\'s what I found, https://pdf.datasheetcatalog.com/datasheet/motorola/MCR106.pdf
Thanks, Mikek