UPDATEEED: Image too wide, does not fit in screen! possible mod?

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UPDATEEED: Image too wide, does not fit in screen! possible mod?

Post by 666sbm »

hello mates, recently i picked up an astro city machine, with a wei-ya 828 monitor.

besides the monitor being installed in a crappy way, it works like a charm.

but im getting a big issue.. image is too wide for the montitor, i have set the hwidth knob to the minimum (minininimmmuummmm) and charachters still appear like a bubble in the edge of the screen.

how can i fix this?

my first tought is to add resistance before the hwidth knowb? or change the potenciometer? dont know if this will work because of.. electronics... if the knob its at its minimum hwidth.. it means that its at maxium resistance.. so adding more resistance will fix this? (by changing the potentiometer or adding a resistance before?)


hope you can help me because monitor is super crisp and i want to play!
Last edited by 666sbm on August 8th, 2017, 2:31 am, edited 1 time in total.
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grantspain
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Re: Image too wide, does not fit in screen! possible mod?

Post by grantspain »

so you have an original nanao ms8-29 tube with a wei ya 828 chassis attached?
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Re: Image too wide, does not fit in screen! possible mod?

Post by 666sbm »

grantspain wrote:so you have an original nanao ms8-29 tube with a wei ya 828 chassis attached?

havent checked the tube brand/model yet. forgot to.

i highly doubt is a nanao ms8 , as it was fitted by the previous owner with some really sketchy parts to the machine ... and it looks brand new
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Re: Image too wide, does not fit in screen! possible mod?

Post by 666sbm »

update.... unidentified tube, no brand on it... been trying to turn the width coil but it wont rotate (machine off, with an allen key) ... not too much foce applied as i dont want to break it....

whats next? should i try harder?
20527392_1639527062785589_11806677_n.jpg
coil.PNG
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Re: Image too wide, does not fit in screen! possible mod?

Post by grantspain »

i think there is a width jumper wire on that chassis-near the hv caps
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Re: Image too wide, does not fit in screen! possible mod?

Post by 666sbm »

update: the hwidth coil is not working (its fixed)

i changed the hwidth potentiometer from 5k to 2k , it seems to fit inside the screen now, but i havent tried it with jamma boards, only with my pc trhough cga adapter. at fists glance it still seems "bubble". will be doing more test this week.

currently image is deformed i have to test the pincush distortion.
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Re: Image too wide, does not fit in screen! possible mod?

Post by 666sbm »

updated.... checked EVERYTHING ...e xcept yoke or chasis voltages.

monitor its still unidentified, with a wei ya 828 chasis.

currente situation:
astro capture.PNG



Im getting 2 thesis now

1- caps damaged
2- chasis is a 28'' with a 29'' screen.. could this be root of the problem?
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Re: UPDATEED: Image too wide, does not fit in screen! possible mod?

Post by Asure »

Looks like you got shafted with the wrong tube/chassis combo. Did you measure the yoke values yet? What are the values for capacitance and resistance for the hori and vertical pairs?
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Re: UPDATEED: Image too wide, does not fit in screen! possible mod?

Post by 666sbm »

Asure wrote:Looks like you got shafted with the wrong tube/chassis combo. Did you measure the yoke values yet? What are the values for capacitance and resistance for the hori and vertical pairs?

havent done it... any good tutorial about doing it? what should i measure.... what should be the differences....
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Re: UPDATEED: Image too wide, does not fit in screen! possible mod?

Post by Asure »

Power off the monitor.
Discharge it.
Beware of shock hazard
Monitor stays off when doing this.
Unplug Monitor after discharging.

There are four wires going to the large copper coil on the neck of the tube. Can be two plugs with two wires or a single 4 wire plug to the chassis. Unplug those connectors.

Set multimeter to ohms and measure the resistance on the two pairs. If possible set multimeter to mH and meter the pairs again. Note down the values.

To meter the inductance you need a multimeter that can do this, not all meters can do this.

Do not forget to plug back in the coil after metering.
Report back the values in the topic :)
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Re: UPDATEED: Image too wide, does not fit in screen! possible mod?

Post by 666sbm »

Asure wrote:Power off the monitor.
Discharge it.
Beware of shock hazard
Monitor stays off when doing this.
Unplug Monitor after discharging.

There are four wires going to the large copper coil on the neck of the tube. Can be two plugs with two wires or a single 4 wire plug to the chassis. Unplug those connectors.

Set multimeter to ohms and measure the resistance on the two pairs. If possible set multimeter to mH and meter the pairs again. Note down the values.

To meter the inductance you need a multimeter that can do this, not all meters can do this.

Do not forget to plug back in the coil after metering.
Report back the values in the topic :)

finally got the monitor out... it was assembled just with magic, not a single bolt.

yoke readings

8.3 ohms vertical
2.1 ohms horizontal ... oscilating

heyyy oscilating? cable was a a piece of crap just 1 hair soldered.
re-soldred it... good readings.

8.1 ohms vrtical
1.6 horizontal

Also.. 1 . horizontal cables are switched ... (somewhere in the middle, they are soldered red with blue, blue with red.)
switch.PNG
dont know if this will affect ( i think not? )

also. 2. i found that chasis has 2 N W (narrow wide) cables.. one is set to N and the other is set to W. ...


also.3 . posting from a potato
Captura.PNG

today i will setup a rig to mount the monitor and chassis to work it in a better way.
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Re: UPDATEED: Image too wide, does not fit in screen! possible mod?

Post by Asure »

Thanks for the readings, that helps.
What are the exact chassis specs?
828? 828h? Any other stickers or writing on it?

Using the pc to test does not help.
Is it set to 640x480? This is the basis screen size for 4:3 vga games. You might get odd screen display if you send 800x600 to it.
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Re: UPDATEEED: Image too wide, does not fit in screen! possible mod?

Post by 666sbm »

finally ... testing.. and... is the chasis busted? or is it incompatible with the tube?


Capture.JPG
SNMK.JPG
wei.JPG
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Re: UPDATEEED: Image too wide, does not fit in screen! possible mod?

Post by Asure »

As you can see, the horizontal is 1.3 and your yoke is around 1.6 (you measured 2.1 at some point?)
Still there's a difference of 0.3 Ohms. I'm not sure how that would translate to actual induction, but the values are off.

I assume the values (HR and VR) printed on the chassis are the maximum that it can manage.

That being said, you could try to email Wei-ya and ask them (in very simple words) if they know how to fix/adapt the chassis for HR 1.6 ohm.
I'm pretty sure they need to use Google Translate, so be very simple with your message.
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Re: UPDATEEED: Image too wide, does not fit in screen! possible mod?

Post by grantspain »

the impedance is not the issue, the problem is the inductance-which you are yet to read
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Re: UPDATEEED: Image too wide, does not fit in screen! possible mod?

Post by atro »

I'm also curious about this.

Seen already a lot of arcade monitors behaving like this, always on the right side of the screen.

Any first steps to look at?
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Re: UPDATEEED: Image too wide, does not fit in screen! possible mod?

Post by Asure »

I've seen this with chassis driving tubes that were close but a little out of spec. For example a few mtc9110 which were badly paired with tubes. Also a single ms9 that i have paired with a .400mH tube has this a little around the edges no matter how I adjust it. (.050 above spec).

I would assume the weiya stuff paired with the end of market egret3 and atomiswave tubes have this a little.
It depends on the yoke and tube specifics and the factory that made them + engineers and quality control.

None of the factory ms8 and ms9 sets I ever saw had this problem. Tube quality and chassis matching involved a lot of specific skill that not all the factories had.

I think I read a few articles about tube factories being set up/moving to India with the same assembly line they had before, but they could not reliably produce quality tubes because of the engineers incapable to create a proper fused electron gun assy for the neck of the tube.

A proper crt television is a marvel of technology, many times undervalued these days.
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