Main Restorations Software Audio/Jukebox/MP3 Everything Else Buy/Sell/Trade
Project Announcements Monitor/Video GroovyMAME Merit/JVL Touchscreen Meet Up Retail Vendors
Driving & Racing Woodworking Software Support Forums Consoles Project Arcade Reviews
Automated Projects Artwork Frontend Support Forums Pinball Forum Discussion Old Boards
Raspberry Pi & Dev Board controls.dat Linux Miscellaneous Arcade Wiki Discussion Old Archives
Lightguns Arcade1Up --- Bug Reports --- Site News

Unread posts | New Replies | Recent posts | Rules | Chatroom | Wiki | File Repository | RSS | Submit news

  

Author Topic: Naomi CRT Swap issue  (Read 1068 times)

0 Members and 1 Guest are viewing this topic.

ID4

  • Trade Count: (0)
  • Full Member
  • ***
  • Offline Offline
  • Posts: 89
  • Last login:Yesterday at 05:31:16 am
    • ID4 Retrodev
Naomi CRT Swap issue
« on: May 05, 2022, 06:17:04 am »
Hi folks!

I have one Sega Naomi Cabinet, the original Toshiba Tube (A68KJU96X) was very damaged, so I swapped the original 29' Toshiba tube for a 29' Philips one (A68ESF002X11 borrowed from a tv).

The Philips tube is mounted *USING* the Toshuba tube original yoke, so the Philips tube is working with the chassis Nanao MS-2934.

Notice that unlike the Toshiba one, the Philips tube don't have magnetic rings, it has the magnetic adjustments made in the factory, inside the electron gun.



The image quality is really amazing, the problem is that I newer get the color purity fixed and always have blue magnetic spots at right corners

I have tried the demagnetizer of the cabinet, it removes something but the spots come out again instantly.



Using the corrrect orientation, I've tried adjusting the yoke by moving it along the neck of the tube, rotating it, tilting it to either side, etc.

Notice that if I move the yoke all the way back, the circle that appears on the screen is moved to the left, I suspect that is the problem.



How I can I fix this? If needed I can add the magnetic rings from another tube to this one, I tried to adjust the chassis but no result.

Thanks in advance!.
« Last Edit: May 05, 2022, 06:20:59 am by ID4 »

lilshawn

  • Trade Count: (+3)
  • Full Member
  • ***
  • Offline Offline
  • Posts: 6875
  • Last login:Today at 11:26:24 pm
  • I break stuff...then fix it...sometimes
Re: Naomi CRT Swap issue
« Reply #1 on: May 05, 2022, 01:15:18 pm »
typically there are chevron shaped magnets attached all over in mas produced tv tubes used to help get things lined up better.

that said... it looks like it's a simple degauss issue here. the purity is good except for some areas in the corner, you usually have to degauss the screen, as the frame of the arcade monitor usually has some pretty hefty magnetic fields stored in it over the years. the old tube would be already degaussed to this metal being so near it.

your TV tube was sitting in a plastic case with no metal around it when it was setup and degaussed so you'll need to degauss this new tube so it's in sync with the magnetic fields all around it now.

ID4

  • Trade Count: (0)
  • Full Member
  • ***
  • Offline Offline
  • Posts: 89
  • Last login:Yesterday at 05:31:16 am
    • ID4 Retrodev
Re: Naomi CRT Swap issue
« Reply #2 on: May 06, 2022, 02:13:43 am »
typically there are chevron shaped magnets attached all over in mas produced tv tubes used to help get things lined up better.

that said... it looks like it's a simple degauss issue here. the purity is good except for some areas in the corner, you usually have to degauss the screen, as the frame of the arcade monitor usually has some pretty hefty magnetic fields stored in it over the years. the old tube would be already degaussed to this metal being so near it.

your TV tube was sitting in a plastic case with no metal around it when it was setup and degaussed so you'll need to degauss this new tube so it's in sync with the magnetic fields all around it now.

Thanks you for you reply! I have already used the degauss button of the machine, the screen "jumps" and the spots disappear but reappear immediately.

Maybe did you refer to other method? Then how effectively demagnetize the tube?

I have googled and found that this Philips tube originally the magnetic rings are included in the yoke, so when I removed the yoke and plugged the Toshiba one, I left the tube without magnetic rings, than can be the cause.

If not, why if I move the yoke all the way back, the circle that appears on the screen is moved to the left?

Thanks !  ;)

lilshawn

  • Trade Count: (+3)
  • Full Member
  • ***
  • Offline Offline
  • Posts: 6875
  • Last login:Today at 11:26:24 pm
  • I break stuff...then fix it...sometimes
Re: Naomi CRT Swap issue
« Reply #3 on: May 06, 2022, 02:31:13 pm »
If not, why if I move the yoke all the way back, the circle that appears on the screen is moved to the left?

because you are affecting the election beam before it has a chance to begin accelerating from the guns. you are probably deflecting particles or making them emit from someplace they aren't supposed to by yanking them out with the magnetic field from the yoke.

the degauss coil on the outside of the tube is good enough to remove a small residual field, but not powerful enough to realign it. you will need to buy/borrow/steal/pay someone to do it with a specific device. you can buy cheapy ones off ebay for like 20 bucks... i dont know how good those are. probably worth a try though. i have a huge industrial type degauss coil (about 14 inches in diameter) for doing CRT's.

https://www.ebay.ca/itm/393969713049?_trkparms=amclksrc%3DITM%26aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D20200818143230%26meid%3Dcf59e465cdf44a3bb58156e13c270003%26pid%3D101224%26rk%3D3%26rkt%3D5%26sd%3D165009205054%26itm%3D393969713049%26pmt%3D0%26noa%3D1%26pg%3D2047675%26algv%3DDefaultOrganicWeb&_trksid=p2047675.c101224.m-1

plug it in, power on the monitor... move in close to the front of the screen, turn it on an wave it around in a circle around the outside of the face as you move  backwards... 1 circle..move back a little...one more...move back... till you are hardly affecting the screen...youll be about 2 or 3 feet away then turn it off.

Zebidee

  • Trade Count: (+8)
  • Full Member
  • ***
  • Offline Offline
  • Posts: 2453
  • Last login:Today at 10:02:17 pm
Re: Naomi CRT Swap issue
« Reply #4 on: May 08, 2022, 03:44:15 am »
I have a couple of those cheap degaussing wands and they work fine.

Word of warning - don't operate them continuously for more than about 10 seconds or so. They will get quite warm and if you leave it on it will start to melt the casing.

If that doesn't work, it may be possible that you need to use some color purity rings with that philips tube/toshiba yoke combo.
Check out my completed projects!


ID4

  • Trade Count: (0)
  • Full Member
  • ***
  • Offline Offline
  • Posts: 89
  • Last login:Yesterday at 05:31:16 am
    • ID4 Retrodev
Re: Naomi CRT Swap issue
« Reply #5 on: May 09, 2022, 04:11:21 am »
If not, why if I move the yoke all the way back, the circle that appears on the screen is moved to the left?

because you are affecting the election beam before it has a chance to begin accelerating from the guns. you are probably deflecting particles or making them emit from someplace they aren't supposed to by yanking them out with the magnetic field from the yoke.

the degauss coil on the outside of the tube is good enough to remove a small residual field, but not powerful enough to realign it. you will need to buy/borrow/steal/pay someone to do it with a specific device. you can buy cheapy ones off ebay for like 20 bucks... i dont know how good those are. probably worth a try though. i have a huge industrial type degauss coil (about 14 inches in diameter) for doing CRT's.

https://www.ebay.ca/itm/393969713049?_trkparms=amclksrc%3DITM%26aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D20200818143230%26meid%3Dcf59e465cdf44a3bb58156e13c270003%26pid%3D101224%26rk%3D3%26rkt%3D5%26sd%3D165009205054%26itm%3D393969713049%26pmt%3D0%26noa%3D1%26pg%3D2047675%26algv%3DDefaultOrganicWeb&_trksid=p2047675.c101224.m-1

plug it in, power on the monitor... move in close to the front of the screen, turn it on an wave it around in a circle around the outside of the face as you move  backwards... 1 circle..move back a little...one more...move back... till you are hardly affecting the screen...youll be about 2 or 3 feet away then turn it off.

Hi!

I have already ordened one of these form aliexpress (11,90 ):



I have also built a degauss coil taking it from a 25' dead tube.



I will try it and and comment how it was.

Thanks you a lot for your help  :cheers:

ID4

  • Trade Count: (0)
  • Full Member
  • ***
  • Offline Offline
  • Posts: 89
  • Last login:Yesterday at 05:31:16 am
    • ID4 Retrodev
Re: Naomi CRT Swap issue
« Reply #6 on: May 09, 2022, 04:13:58 am »
I have a couple of those cheap degaussing wands and they work fine.

Word of warning - don't operate them continuously for more than about 10 seconds or so. They will get quite warm and if you leave it on it will start to melt the casing.

If that doesn't work, it may be possible that you need to use some color purity rings with that philips tube/toshiba yoke combo.

Hi!

Ok thanks, I will use it carefully. I can get some complete magnetic rings kit form 28' CRTs that I have in storage.

Thanks!

 ;)

ID4

  • Trade Count: (0)
  • Full Member
  • ***
  • Offline Offline
  • Posts: 89
  • Last login:Yesterday at 05:31:16 am
    • ID4 Retrodev
Re: Naomi CRT Swap issue
« Reply #7 on: May 10, 2022, 02:17:13 pm »
If not, why if I move the yoke all the way back, the circle that appears on the screen is moved to the left?

the degauss coil on the outside of the tube is good enough to remove a small residual field, but not powerful enough to realign it. you will need to buy/borrow/steal/pay someone to do it with a specific device. you can buy cheapy ones off ebay for like 20 bucks... i dont know how good those are. probably worth a try though. i have a huge industrial type degauss coil (about 14 inches in diameter) for doing CRT's.


Hi!

Have tried the made by me degauss coil, no result the spots still there. The effect it produced in the screen is like the cabinet degauss coil, seems low powered.

 :-[ Waiting for the Aliexpress one.

lilshawn

  • Trade Count: (+3)
  • Full Member
  • ***
  • Offline Offline
  • Posts: 6875
  • Last login:Today at 11:26:24 pm
  • I break stuff...then fix it...sometimes
Re: Naomi CRT Swap issue
« Reply #8 on: May 10, 2022, 04:47:47 pm »
Unfortunately, you cant just twist an existing degauss coil into a loop like that, as you end up with parts of the coil tuning one direction and other parts of the loop turning in the opposite direction then when you try to use it. this is because the degauss loop (if you pull it out into it's biggest loop as it was), the wire goes in and then around 30 or 40 times then back out again with a magnetic field that goes in a direction on one side...and the "opposite" to the side facing you on the other. (see pic for a single wire representation of the coil wire magnetic field)  when you twist it into a smaller loop like that, you end up turning the other side of the loop back in the opposite direction back over itself...so, most of the magnetic field produced ends up running back in the opposite direction, canceling itself out. You would need to pull all the wire out and rewind it into a (smaller) continuous direction loop for it to work. (so that all the magnetic fields produced go in the correct direction.

ID4

  • Trade Count: (0)
  • Full Member
  • ***
  • Offline Offline
  • Posts: 89
  • Last login:Yesterday at 05:31:16 am
    • ID4 Retrodev
Re: Naomi CRT Swap issue
« Reply #9 on: May 11, 2022, 03:04:12 am »
Unfortunately, you cant just twist an existing degauss coil into a loop like that, as you end up with parts of the coil tuning one direction and other parts of the loop turning in the opposite direction then when you try to use it. this is because the degauss loop (if you pull it out into it's biggest loop as it was), the wire goes in and then around 30 or 40 times then back out again with a magnetic field that goes in a direction on one side...and the "opposite" to the side facing you on the other. (see pic for a single wire representation of the coil wire magnetic field)  when you twist it into a smaller loop like that, you end up turning the other side of the loop back in the opposite direction back over itself...so, most of the magnetic field produced ends up running back in the opposite direction, canceling itself out. You would need to pull all the wire out and rewind it into a (smaller) continuous direction loop for it to work. (so that all the magnetic fields produced go in the correct direction.

Hi!

Woww what a explanation! thanks you a lot I will rewind it and try again! :cheers:

lilshawn

  • Trade Count: (+3)
  • Full Member
  • ***
  • Offline Offline
  • Posts: 6875
  • Last login:Today at 11:26:24 pm
  • I break stuff...then fix it...sometimes
Re: Naomi CRT Swap issue
« Reply #10 on: May 11, 2022, 01:00:57 pm »
an easy solution is if you have a big electric soldering gun like this, you can use it as a rudimentary degausser, as on the inside, it has a large coil of wire same as a commercial type degausser.




AstroFan

  • Trade Count: (0)
  • Jr. Member
  • **
  • Offline Offline
  • Posts: 8
  • Last login:Today at 01:08:26 pm
Re: Naomi CRT Swap issue
« Reply #11 on: May 23, 2022, 04:58:01 pm »
Any news on this?  Sorry, but I'd really like to know if the chassis does work on the Philips tube.

Btw. I've read on other forums that the factory pre-adjustment of Philips tubes does only work with the original yoke.
AFAIK (or remember) the plastoferrite sleeve that sits towards the back of the yoke is the part that is adjusted, and if using another yoke,
 the usual magnetic rings have to be used.

lilshawn

  • Trade Count: (+3)
  • Full Member
  • ***
  • Offline Offline
  • Posts: 6875
  • Last login:Today at 11:26:24 pm
  • I break stuff...then fix it...sometimes
Re: Naomi CRT Swap issue
« Reply #12 on: May 23, 2022, 05:36:56 pm »
most color TUBES are the same... about the only difference is if it's a single focus or dual focus gun setup. otherwise the pinouts and everything are the same irrespective of the gun directions (horizontal or triode stacked or whatever is moot.)

the main difference is the yoke, they are all almost different and depend on the frequency being driven and whatnot... and if you change the old yoke over to the donor tube, it's nothing to worry about.

ID4

  • Trade Count: (0)
  • Full Member
  • ***
  • Offline Offline
  • Posts: 89
  • Last login:Yesterday at 05:31:16 am
    • ID4 Retrodev
Re: Naomi CRT Swap issue
« Reply #13 on: May 26, 2022, 10:25:03 am »
Any news on this?  Sorry, but I'd really like to know if the chassis does work on the Philips tube.

Btw. I've read on other forums that the factory pre-adjustment of Philips tubes does only work with the original yoke.
AFAIK (or remember) the plastoferrite sleeve that sits towards the back of the yoke is the part that is adjusted, and if using another yoke,
 the usual magnetic rings have to be used.

Hi!

Except for the magnetic stains, the tube works pefect.

I have still waiting for the degauss tool form aliexpress, or to make the mine as lilshawn explained.


I'll comment when I try it.

Thanks

ID4

ID4

  • Trade Count: (0)
  • Full Member
  • ***
  • Offline Offline
  • Posts: 89
  • Last login:Yesterday at 05:31:16 am
    • ID4 Retrodev
Re: Naomi CRT Swap issue
« Reply #14 on: June 06, 2022, 08:21:16 am »
Hi!


The aliexpress degausser didn't worked, it's like using the chassis one.

So I need to try to buy or to build one like lilshawn explained.

Thanks!

ID4

AstroFan

  • Trade Count: (0)
  • Jr. Member
  • **
  • Offline Offline
  • Posts: 8
  • Last login:Today at 01:08:26 pm
Re: Naomi CRT Swap issue
« Reply #15 on: June 06, 2022, 01:17:38 pm »
Have you tried putting magnetic rings from another yoke/tube or restoring the original magnetized sleeve yet?

ID4

  • Trade Count: (0)
  • Full Member
  • ***
  • Offline Offline
  • Posts: 89
  • Last login:Yesterday at 05:31:16 am
    • ID4 Retrodev
Re: Naomi CRT Swap issue
« Reply #16 on: June 07, 2022, 04:25:43 am »
Have you tried putting magnetic rings from another yoke/tube or restoring the original magnetized sleeve yet?

Hi!

If I can't demagnetize it, I plan to try putting magnetic rings form another tube, and then adjust it.

Thanks!

ID4

ID4

  • Trade Count: (0)
  • Full Member
  • ***
  • Offline Offline
  • Posts: 89
  • Last login:Yesterday at 05:31:16 am
    • ID4 Retrodev
Re: Naomi CRT Swap issue
« Reply #17 on: Yesterday at 04:58:38 am »
Hi!

I have a Sanwa 29es31 chassis on hand

Is this chassis compatible with the original Naomi/Nano tube/yoke (Toshiba A68KSM696X)?

Remember that I am using the A68KSM696X yoke with the philips tube.

Thanks!

ID4

lilshawn

  • Trade Count: (+3)
  • Full Member
  • ***
  • Offline Offline
  • Posts: 6875
  • Last login:Today at 11:26:24 pm
  • I break stuff...then fix it...sometimes
Re: Naomi CRT Swap issue
« Reply #18 on: Today at 11:14:49 am »
you need a special meter called an LCR meter to properly measure the horizontal and vertical yoke windings and see if they are close enough to the original.

your horizontal inductance should be within about ~0.05 uH and the vertical within ~0.3 uH without having to change anything and your regular screen controls can make up for the difference... otherwise you are looking at changing tuning the capacitors in the horizontal to try and make up for it. any further than ~0.15 uH on the horizontal and ~1uH on the vertical from the original, will likely blow up the chassis when powered on.



you can KIND OF measure it with an ohm meter to find out if it's close, but your really need to find out what the natural oscillation frequency of the coils are otherwise they yoke will fight the current being put out by the chassis and run really hot... or just plain blow up when you first power it on.

the yoke is essentially a coil of wire that has a natural flow of current in and out and does not create resistance. if operated outside of this natural flow in and out, the coil resists the change and becomes a blockage in the circuit. other parts of the circuit relying on this current flowing through unrestricted will fail.