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Lines on top of New Net City monitor and now it’s dead.... Help!

Posted: April 5th, 2021, 8:45 am
by Buddyc
Hi!

I got my second New Net City a couple of months ago and it has worked great, but has a weird issue when using 31khz systems.
For a minute of two after I turn on my NNC, I get som white lines on top of the image.
They slowly disappear after about 2 minutes, but I guess it something that needs to be addressed sooner or later.
Not notable in 15Khz. Only 31Khz.
Picture is also slightly more “shaky” than my other NNC, but trying to capture this on video was not possible. It’s so subtle that only viewable at close, but something is definitely “off”...
It’s a PD1843 chassis that supposedly was recaped in November 2020, but maybe the seller messed up?

Could this be a cap related issue? Maybe something around the vertical section?

Any tips and or recommendations are most welcome since I have never worked on this type of chassis before.

Added some pictures of the MISTer at boot up since you can see the lines pretty good. Same issues when using Naomi, Type X2, Exa-arcadia etc etc.
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After about two minutes. All gone.
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Re: Lines on top of New Net City monitor

Posted: April 5th, 2021, 8:48 am
by Buddyc
No issues with image quality besides a kind of “shaky” image. Really subtle shaking, but still annoying :awe:
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Re: Lines on top of New Net City monitor

Posted: April 5th, 2021, 9:54 am
by grantspain
if you look around the vertical deflection ic you will see a few caps, these always go bad- replace them and you should be ok but be aware there could be other caps on the chassis, if you inspect most and look underneath at the legs look for any sign of leakage like a green deposit

Re: Lines on top of New Net City monitor

Posted: April 5th, 2021, 11:28 am
by nem
Buddyc wrote:
April 5th, 2021, 8:45 am
It’s a PD1843 chassis that supposedly was recaped in November 2020, but maybe the seller messed up?
Maybe they skipped some or put the 'wrong' caps in.

Re: Lines on top of New Net City monitor

Posted: April 5th, 2021, 12:31 pm
by Buddyc
Thanks for the advice!

I guess it’s best that I pull the chassis and go into inspection mode.

Re: Lines on top of New Net City monitor

Posted: April 5th, 2021, 3:05 pm
by Buddyc
Looks like I have all the caps I need to possibly fix this, but a quick follow up question.

Would it be ok to replace a 33uf 16V cap with a 33uf 63V cap?
Same uf. Higher voltage.

Safe or stupid?

Re: Lines on top of New Net City monitor

Posted: April 5th, 2021, 7:15 pm
by grantspain
yes all good, must consider physical size though to whether it will fit nicely

Re: Lines on top of New Net City monitor

Posted: April 5th, 2021, 7:29 pm
by Buddyc
Awesome! Thanks again!

Re: Lines on top of New Net City monitor

Posted: April 8th, 2021, 12:01 am
by Buddyc
Well.... **** on a stick....

Did the recap and was extra cautious and took my time making sure everything was placed correctly, but now the screen does not power up. I have neck glow and I can hear it start, but no image whatsoever....

Help?

Re: Lines on top of New Net City monitor and now it’s dead.... Help!

Posted: April 8th, 2021, 12:43 am
by Buddyc
I can hear the degauss starting. No fuses blown No caps have bursted. Neck glow is ok and I can hear the yoke is getting power. Looks like the flyback is not starting... crap!

Any tips on where to look?

Re: Lines on top of New Net City monitor and now it’s dead.... Help!

Posted: April 8th, 2021, 7:30 am
by grantspain
have tried increasing the screen volts on the flyback?

Re: Lines on top of New Net City monitor and now it’s dead.... Help!

Posted: April 8th, 2021, 12:24 pm
by Buddyc
grantspain wrote:
April 8th, 2021, 7:30 am
have tried increasing the screen volts on the flyback?
Yes. Nothing happened. It’s like everything turns on, but not the flyback.
It’s strange that I get neck glow, but nothing from the flyback.

Any words of advice?

Re: Lines on top of New Net City monitor and now it’s dead.... Help!

Posted: April 8th, 2021, 3:09 pm
by Buddyc
Does anybody know how to measure B+ on a Toshiba PD2367 chassis?

Re: Lines on top of New Net City monitor and now it’s dead.... Help!

Posted: April 8th, 2021, 5:10 pm
by grantspain
how careful were you replacing the caps, you should check every cap you changed for broken tracks

check all fuses including the pico fuse

Re: Lines on top of New Net City monitor and now it’s dead.... Help!

Posted: April 8th, 2021, 5:14 pm
by Buddyc
grantspain wrote:
April 8th, 2021, 5:10 pm
how careful were you replacing the caps, you should check every cap you changed for broken tracks

check all fuses including the pico fuse
I was super carful, but I am no expert at all. Seriously don’t trust my own skills right now...
Will pull the chassis out later tonight and take some pictures. Hope I can find the culprit.

Thanks again for the assistance this far Grant. Really appreciate it!

Re: Lines on top of New Net City monitor and now it’s dead.... Help!

Posted: April 8th, 2021, 5:16 pm
by Buddyc
Ps. Do you know what the pico fuse looks like and the location?

Re: Lines on top of New Net City monitor and now it’s dead.... Help!

Posted: April 8th, 2021, 7:03 pm
by grantspain
post some photos later and i will point out the pico fuse

Re: Lines on top of New Net City monitor and now it’s dead.... Help!

Posted: April 8th, 2021, 8:42 pm
by Buddyc
grantspain wrote:
April 8th, 2021, 7:03 pm
post some photos later and i will point out the pico fuse
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Re: Lines on top of New Net City monitor and now it’s dead.... Help!

Posted: April 8th, 2021, 8:43 pm
by Buddyc
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Re: Lines on top of New Net City monitor and now it’s dead.... Help!

Posted: April 8th, 2021, 8:52 pm
by Buddyc
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