Problem Arcing in tube neck

JohnT

JohnT

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So the monitor was working, bit washed out but had an image.
I recapped the MTC 9110 chassis, connected back up and was faced with this lightning in a bottle….arcing/purple.

Video to it here:

I’ve seen a few comments on here about purple being that the tubes got air in it, but I’ve checked the neck and can’t see any kind of crack. Also from what I hear I would have noticed if the tube had lost its vacuum, but really not sure where to go from here with this.

Any thoughts?
 
JohnT

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Such a shame - is it odd that I didn’t notice any of the air rushing in or anything that would have been obvious?
 
JohnT

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I do have an A59ECY13x31 25" tube, but I don't know if this would be compatible with the MTC 9110 chassis and I can't see much online about those monitors.
Anyone here know if it would work?
 
V

Visualimageservices

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Just be aware when you fit a new tube.
This kind of fault is normally caused by line flyback tunning caps at fault - not air
You said that you recapped the chassis ?? - I bet you have replaced a cap that should not be their or a complete wrong value - check your work before switching on with the new tube
 
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Georgian2

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Visualimageservices said:
Just be aware when you fit a new tube.
This kind of fault is normally caused by line flyback tunning caps at fault - not air
You said that you recapped the chassis ?? - I bet you have replaced a cap that should not be their or a complete wrong value - check your work before switching on with the new tube
Click to expand...
Care to explain more? This means the tube is still good?
 
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Visualimageservices

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Georgian2 said:
Care to explain more? This means the tube is still good?
Click to expand...
No your tube is gone - the high flyback voltage can cause this - and sometimes blows the tube neck off - if this is the case - a replacement tube will suffer the same results.
Did you replace any caps around the flyback transformer - these are normally rated in the 1600v / 2000v range
 
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Georgian2

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Visualimageservices said:
No your tube is gone - the high flyback voltage can cause this - and sometimes blows the tube neck off - if this is the case - a replacement tube will suffer the same results.
Did you replace any caps around the flyback transformer - these are normally rated in the 1600v / 2000v range
Click to expand...
It's not my tube. I am just curious.
Dosen't the x-ray protection kick in if the voltage is to high? It must be very high in order to arch so much. Maybe the x-ray protection is not working.
 
JohnT

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Visualimageservices said:
Just be aware when you fit a new tube.
This kind of fault is normally caused by line flyback tunning caps at fault - not air
You said that you recapped the chassis ?? - I bet you have replaced a cap that should not be their or a complete wrong value - check your work before switching on with the new tube
Click to expand...
I checked the caps being taken off to the ones being provided in the kit and made sure they were the right value and polarity. Just checked again just in-case and they're the correct values.

Only the below caps were replaced, none of the HV polypropylene capacitors around the flyback were touched.

AreaPositionCap
Neck BoardC20122uf 50v
Neck BoardC20510uf 250v
Main BoardC59100uf 35v
Main BoardC231uf 100v
Main BoardC3522uf 50v
Main BoardC161000uf 16v
Main BoardC221uf 50v
Main BoardC3422uf 200v
Main BoardC5422uf 250v
Main BoardC561uf 250v
Main BoardC451uf 250v
Main BoardC1447uf 16v
Main BoardC647uf 16v
Main BoardC151000uf 16v
Main BoardC5810uf 50v
Main BoardC571000uf 35v
Main BoardC381uf 100v
Main BoardC9100uf 35v

Any guidance on checking the chassis before connecting up to another tube?
 
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Visualimageservices

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JohnT said:
I checked the caps being taken off to the ones being provided in the kit and made sure they were the right value and polarity. Just checked again just in-case and they're the correct values.

Only the below caps were replaced, none of the HV polypropylene capacitors around the flyback were touched.

AreaPositionCap
Neck BoardC20122uf 50v
Neck BoardC20510uf 250v
Main BoardC59100uf 35v
Main BoardC231uf 100v
Main BoardC3522uf 50v
Main BoardC161000uf 16v
Main BoardC221uf 50v
Main BoardC3422uf 200v
Main BoardC5422uf 250v
Main BoardC561uf 250v
Main BoardC451uf 250v
Main BoardC1447uf 16v
Main BoardC647uf 16v
Main BoardC151000uf 16v
Main BoardC5810uf 50v
Main BoardC571000uf 35v
Main BoardC381uf 100v
Main BoardC9100uf 35v

Any guidance on checking the chassis before connecting up to another tube?
Click to expand...
They are standard electrolytic caps , don,'t think they would have caused it - unless one is the wrong way around like c22 or c23 whi h would increase ht voltage - or bad soldering / shorting out somewhere
 
JohnT

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Visualimageservices said:
They are standard electrolytic caps , don,'t think they would have caused it - unless one is the wrong way around like c22 or c23 whi h would increase ht voltage - or bad soldering / shorting out somewhere
Click to expand...
They're both the right way round. No idea then.
Is it possible to test the chassis off the tube?
 
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