Another Nanao ms-2931 buzzer

[RandomRetro]

So have a Nanao 2931 with a solid buzz. Seems to be consistent with this thread well covered by @ekorz. Looking forward to seeing what I find inside the yoke but suspect some crisp convergence strips or something.

https://www.arcade-projects.com/threads/nanao-ms-2931-buzz-fixed.10712/

Here is the video of my buzzing yoke... link here

Any guidance on best way to take the yoke off the tube? Basically can you keep the black feet attached to the tube and just cut back the silastic/glue stuff, or just take the feet off too?

 

[hoagtech]

So have a Nanao 2931 with a solid buzz. Seems to be consistent with this thread well covered by @ekorz. Looking forward to seeing what I find inside the yoke but suspect some crisp convergence strips or something.

https://www.arcade-projects.com/threads/nanao-ms-2931-buzz-fixed.10712/

Here is the video of my buzzing yoke... link here

Any guidance on best way to take the yoke off the tube? Basically can you keep the black feet attached to the tube and just cut back the silastic/glue stuff, or just take the feet off too?

I start by marking my convergence ring locations and a couple marks on the tube glass and yoke so you know where to slide the rings and yoke when reassembling.

Loosen the convergence clamp near the back of the neck.

Loosen the yoke hose clamp.

Grip the yoke with both hands and rotate a little and pull back. It should come right off.


I didn’t need to cut any adhesive on my 2931.

 

[RandomRetro]

I start by marking my convergence ring locations and a couple marks on the tube glass and yoke so you know where to slide the rings and yoke when reassembling.

Loosen the convergence clamp near the back of the neck.

Loosen the yoke hose clamp.

Grip the yoke with both hands and rotate a little and pull back. It should come right off.


I didn’t need to cut any adhesive on my 2931.

Makes sense. I am thinking about putting some hot glue across the convergence rings to help keep them in place. The black feet have an adhesive that is holding them to the CRT, and then there is the white silastic that seems to be holding the feet and the coil housing to the CRT some. I am just being cautious and taking it slow and finding out what I might need to look for as I dive in. So yeah, noob here

 

[RandomRetro]

These convergence rings are pretty stuck on here...

 

[RandomRetro]

So the yellow glue on the convergence rings leaked down and made removal a little tricky, but got it done.

Yoke housing had some Silastic holding it tight, but a little cutting and got things loose but when this was attached originally they went heavy on the stuff so a little was inside on the coils. Caught it before any real damage but it pulled one coil wire a little.

Tucked things back in to their happy place and took off a little of the Silastic stuff.

And man is there some seriously brittle and burnt tape in here...

So the question is do I remove all this brittle tape and replace it with something or leave it off? And if I replace it, what kind of tape do I use and where do I get it?

 

[RandomRetro]

Cleaned up the tape.

 

[RandomRetro]

Fished cleaning things up and added some electrical tape to keep factory strips in place.

Noticed something rattling around and took a bit of work but found two pieces of metal that were bouncing around in the yoke housing.

Plugged things back in and looking and sounding good. Now to recap while I have the monitor pulled.

 

[RandomRetro]

So wrapping up this thread, but did a full clean and restore since the monitor was pulled...

• Full recap of the chassis
• Tested emissions and leakage, and a clean/balance with B&K 470 Rejuvenator (w/ help from @opt2not)
• Adjusted tilt with yoke
• Reworked corner convergence with some convergence strips (w/ help from @everten)
• Adjusted brightness and focus on flyback

Slight convergence still in top left corner, and a little bowing down in top right. But overall, a bit improvement, and no more crazy buzzing from the yoke!

 

[everten]

Very nice work man! Keep it up.