Does anyone repair yokes? Is it even possible? (WTB - Red Tent XM-1801 yoke)

[TheYeti]

Does anyone repair yokes? Is it even possible? (WTB - Red Tent XM-1801 yoke)

I fear that I already know the answer to this but here it goes anyway....

I'm sitting on 3 broken XM-1801 (Nintendo Red Tent) yokes right now! AHHHH!

I know these yokes are not the easiest to find so it seems like a shame that they are not being reproduced...or at least repaired.

I'd love to tackle this project of "rewinding" my own yoke but I'm afraid that all 3 of my broken ones have a defective interior winding. The interior winding seems like it would be the most difficult (impossible?) to repair.

Does anyone do this? Is it even possible?

 

[VectorCollector]

The only person I know who does yokes (mainly vector) is ArcadeJason.

 

[TheYeti]

The only person I know who does yokes (mainly vector) is ArcadeJason.

Thanks VC, I'll send a message to ArcadeJason. (Love his YouTube channel, by the way)

Man...it's really a huge bummer. The yokes are by far the weakest point on these monitors. I'm seeing them fail everywhere. It's going to be the downfall of all Red Tents.

 

[andrewb]

How are you confirming that they are bad?

 

[TheYeti]

How are you confirming that they are bad?

I'm validating this a couple of ways:

1. I have known working yokes that I can swap

2. The B+ voltage on my chassis is dropping to 75VDC with the bad yoke. (Should be 110VDC normally)

3. I am probing around the corroded portion of the yoke with my multi-meter on continuity and it's beeping. (short)

4. Visually seeing smoke rise up from one of the yokes when powered on. LOL

5. Yoke is producing erratic static visually and audibly on the CRT screen.

5. Another yoke was so corroded the copper wire literally broke free. (In a spot I couldn't repair it)

6. And another yoke produces an image but smells pretty bad after only being powered on for a few seconds. The image on the screen is massively out of convergence.

 

[andrewb]

Interesting. The enamel they used on the wire must have been cheaper than other yokes, as magnet wire is usually pretty tough stuff. (Or something else in the cab/design is causing it to come off.)

I'd say you're probably SOL. Repairing them isn't going to be easy, especially if the enamel is as bad as you say, such that you can probe it with a DMM and get shorts. That means it's a massive failure/delamination of the enamel.

 

[TheYeti]

Interesting. The enamel they used on the wire must have been cheaper than other yokes,

Bingo...I'm pretty sure they used shotty enameled wired in the factory on these yokes. I'm seeing post after post after post of burned up yokes with this monitor.

Ugh! This is such a huge bummer man!

I just paid over $350 to have a replacement tube shipped to me and I don't have a working yoke to go with it.

Right now this tube is a $350 paperweight if I can't get a working yoke.

Curse you Nintendo! Why did you have to put such a goofy/crappy monitor in the red tent!!!

 

[andrewb]

There are enough broken/necked/trashed tubes out there from red tents, I'm sure you can find a spare yoke somewhere.

Edit the title of this thread to say 'WTB - Red Tent XM-1801 yoke'.

 

[VectorCollector]

I had a bad K7000 yoke. It (and the game) were sitting somewhere and conveniently it seems some drywall fluid leak dripped into the cabinet air exhaust vent at the top of the cabinet. It dripped onto the yoke (and main chassis board). The acidic nature of the fluid caused the yoke winding to corrode and "short". (The chassis board had open copper traces). I ohmed the yoke wires out and found the shorted area ... tried to fix but was unsuccessful. The only "real" solution was to purchase a replacement on KLOV. And that worked.

The bad yoke, BTW, had the keystoning phenomenon.

Typically a good/bad yoke is determined, as well, by the H/V impedances being in spec or not.

 

[TheYeti]

There are enough broken/necked/trashed tubes out there from red tents, I'm sure you can find a spare yoke somewhere.

Edit the title of this thread to say 'WTB - Red Tent XM-1801 yoke'.

I already started a WTB thread in the wanted section.

I don't want to spam the "monitor" section with a WTB ad if that isn't OK?

 

[TheYeti]

I had a bad K7000 yoke. It (and the game) were sitting somewhere and conveniently it seems some drywall fluid leak dripped into the cabinet air exhaust vent at the top of the cabinet. It dripped onto the yoke (and main chassis board). The acidic nature of the fluid caused the yoke winding to corrode and "short". (The chassis board had open copper traces). I ohmed the yoke wires out and found the shorted area ... tried to fix but was unsuccessful.

Interestign you should mention that because many people have a another theory as to why the yokes on these red tents are dying so often....it's becasue people set their drinks on top of the machine. The drink would inevitable spill, leaking corrosive fluid down on the monitor. The yoke would act as a "cup" catching all the fluid. Thus, sitting there heating up and chewing away at the enamel.

Typically a good/bad yoke is determined, as well, by the H/V impedances being in spec or not.

On 2 of the 3 bad yokes I have (as far as I can tell) when I ohm them out, they are within spec. So that kinda surprised me that they didn't work. But then again...they definitely had open traces so even if they ohm out...that's not a guarantee they will work.

 

[ArcadeJason]

sent a pm explaining how to repair it but i will post it here again for people in the future.

#1 find a donor yoke of similar inner coil inductance and of the same deflection angle
#2 separate the outer coils from your yoke and reuse them on the donor yoke (there are 2 common ferrite molds amongst all manufacturers for 90 degree yokes)
#3 OR replace the entire yoke with a compatible unit from a tv or monitor


luckily the inner yoke coils of most raster and vector yokes are compatible with each other but please test them first.

it is commonly the outer coils which differ so vastly

 

[ArcadeJason]

Interestign you should mention that because many people have a another theory as to why the yokes on these red tents are dying so often....it's becasue people set their drinks on top of the machine. The drink would inevitable spill, leaking corrosive fluid down on the monitor. The yoke would act as a "cup" catching all the fluid. Thus, sitting there heating up and chewing away at the enamel.



On 2 of the 3 bad yokes I have (as far as I can tell) when I ohm them out, they are within spec. So that kinda surprised me that they didn't work. But then again...they definitely had open traces so even if they ohm out...that's not a guarantee they will work.

this is a reason why testing impedance is more important than testing resistance when it comes to an inductor.
if you were to short out only 1 single yoke winding in other words make 1 single shorted loop of wire your resistance will pretty much be the same . but it would throw the inductance way off since that single coil of wire is producing a current and is being directly shorted

 

[Alpha-tron]

I wonder if a 20ez yoke would work?

Or maybe a 20ez chassis and yoke with the red tent tube will work.

 

[TheYeti]

I wonder if a 20ez yoke would work?

Or maybe a 20ez chassis and yoke with the red tent tube will work.

Courtesy of Ken Layton, here are the specs for each. Unfortunately, they don't match up.

SHARP XM-1801 (Red Tent)
CRT: Sharp # 470NVB22, 8 pin, 22.5 mm diameter neck
B&K Rejuvenator adapter: CR-31
Horizontal yoke winding: red & blue, 2 ohms
Vertical yoke winding: green & yellow, 15 ohms
Yoke part number: H1394CE
Flyback part number: F1408CE (4111A)

Sanyo 20-EZ:
CRT: # 510UTB22, 10 pin, 29mm diameter neck
B&K Rejuvenator adapter: CR-23
Horizontal yoke winding: red & blue, 2 ohms
Vertical yoke winding: green & yellow, 50 ohms

 

[Chuck12]

Courtesy of Ken Layton, here are the specs for each. Unfortunately, they don't match up.

SHARP XM-1801 (Red Tent)
CRT: Sharp # 470NVB22, 8 pin, 22.5 mm diameter neck
B&K Rejuvenator adapter: CR-31
Horizontal yoke winding: red & blue, 2 ohms
Vertical yoke winding: green & yellow, 15 ohms
Yoke part number: H1394CE
Flyback part number: F1408CE (4111A)

Sanyo 20-EZ:
CRT: # 510UTB22, 10 pin, 29mm diameter neck
B&K Rejuvenator adapter: CR-23
Horizontal yoke winding: red & blue, 2 ohms
Vertical yoke winding: green & yellow, 50 ohms

A yoke out of a XM2001 may work for you, it's definitely worth a try as you may have to adjust the "size" by changing the yoke spacers on the neck.

 

[TheYeti]

A yoke out of a XM2001 may work for you, it's definitely worth a try as you may have to adjust the "size" by changing the yoke spacers on the neck.

That's a good point. They do share the same chassis. And the specs do match up.

Sharp XM-2001:
CRT: Sharp # 510YWB22, 8 pin, 22.5mm diameter neck
B&K Rejuvenator adapater: CR-31
Horizontal yoke winding: red & blue, 2 ohms
Vertical yoke winding: green & yellow, 15 ohms

 

[Alpha-tron]

I saw your wanted sign. I was hoping the 20ez tube would at least be the same size and you could have just stolen the horizontal part of the yoke but the tube neck is different diameter so while you could sort of make it work. It be unstable and finicky repair at most.


Over at banning, john has a bone yard of necked tubes.
I am going to see if I can find you something. I have brought and donated a bunch of dead monitors just to have spare parts.

We have about 8 100v japanese crts. I am not sure what tube is inside I believe they where thin neck tube.

I going to look what I have at whitter and garden grove today..
You going to have to wait until this Saturday to see what John has..

I would like you find a workable solution cause banning has several of these machines and one basket case one with both crts that were pulled out of them. I have a sneaky idea that the two pulled crts might have the same yoke issues.

Will post back if I can find something today and post again this Saturday if John has something

 

[Braido]

I have the exact same situation with my Red Tent. Even purchased a new chassis and Yoke and the new yoke also did the same thing. The inside of my Yokes that are bad on my Red Tent look just like yours. I also get the same symptoms as you did, smoke from yokes, etc...

I'll be following this thread hoping for a fix,

 

[andrewb]

Dumb question, but are you guys sure there isn't something about your chassis that are burning up yokes?

I like the soft drinks theory, but am wondering what else could potentially cause this. I do like drilling into systematic failures like this, so I'm interested to understand what the root cause is here.