Jump to content
Due to a large amount of spamers, accounts will now have to be approved by the Admins so please be patient. ×
  • 0
IGNORED

Green gun seems to keep firing


slampt

Question

13 answers to this question

Recommended Posts

  • 0
Spark gap on the green cathode has become partially conductive. If this is the case, removing the gap is easy and quick before checking other things in the green circuit. Mentioning the monitor model and posting a pic of the neckboard would help.
Link to comment
Share on other sites

  • 0

Those are not relevant. Desolder the brown spark gap closest to the blue cap. It's for protection. In case of a flashover inside the tube it attracts the spark that would otherwise damage the cathode and discharges it to ground. If it's defective it could leak to ground and that would explain the excess of green (a complete short across the cathode and ground would give a full green screen). So this is easy to check as a first step. If the green streak is still there you'll have to troubleshoot other components in the green circuit (diodes and transistors) and that's more complicated.

 

Similar problem on a MS9:

https://forum.arcadeotaku.com/viewtopic.php?f=4&t=31401&p=439663

Link to comment
Share on other sites

  • 0
Your red/blue plug horizontal yoke is in the wrong section..Need to line up it next to the vertical plug.

 

Genuine questions: given there are visibly two whole yoke connectors on the board, why the double? Are they just vertical mirrors, for a complete 4-in-line plug that hasn't been snapped in half? If so, why does matter which way around the plugs are, as long as the image looks right (and of course, you never mix vertical and horizontal)?

Link to comment
Share on other sites

  • 0
Genuine questions: given there are visibly two whole yoke connectors on the board, why the double? Are they just vertical mirrors, for a complete 4-in-line plug that hasn't been snapped in half? If so, why does matter which way around the plugs are, as long as the image looks right (and of course, you never mix vertical and horizontal)?

vertical yoke plugged in 15k and horizontal plugged in 24K.

Are you sure he has taken the right picture image ?:lol

Have you ever worked on Nanao Chassis before @buttersoft ?:o

Link to comment
Share on other sites

  • 0
vertical yoke plugged in 15k and horizontal plugged in 24K.

Are you sure he has taken the right picture image ?:lol

Have you ever worked on Nanao Chassis before @buttersoft ?:o

 

Only older stuff, i'm really only working on the stuff i have. And paying attention to other threads so i can learn, of course :)

 

Cheers for the reply. I didn't know anything worked that way, i would have thought it was all handled elsewhere and then just pushed out through the same yoke connector.

Link to comment
Share on other sites

  • 0

Hey Joe ,

 

Mate if that was a problem on the neck board it would be displayed as the screen fully saturated in Green and retrace lines, with Blue and Red only visible in the background, so the problem is not neck board related.

The fact the green is in the correct color bar means the signal going into the chassis and through the color amp module on the chassis is being over amplified.

The amplifier section is clamped to 5.1v coming in but you should only be getting around 3.0vdc on each color coming in to the chassis input connector, if the input voltage is higher than 4.0v the problem is coming from one of the color drives on the bottom layer of the game board ( easy to verify just swap the game board to the other side and see if the problem follows ) , if you swap the board and voltage stays above 4.0v then swap the filter board that connects to the front of the game board stack ( the filter board has resistor/capacitor network for each output, when the resistor inside goes open circuit which holds the output below 4.0v you will get this over driving problem) , when the capacitor shorts you will read 5.0v from the effected color.

 

If all voltages compared to each on each color are about the same then the problem is with the color amp module on the chassis, what ever you find the fix is simple just drop it in and I'll see if I can sort it out while you wait.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...