The NEW Build Your Own Arcade Controls
Main => Monitor/Video Forum => Topic started by: mark_m on November 22, 2009, 05:12:08 pm
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Hi all,
I need help! My WG monitor's screen shakes when the monitor is in lower resolution modes. I have recapped the monitor with a kit from Bob Roberts and need help with what part(s) I need to buy or adjustments to make next.
Wells Gardner U3000 - 27K3003 Problem (http://www.youtube.com/watch?v=LP8B5PdJL7w#)
Thanks in advance!
-Mark
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I ordered a new B+ Filter, hopefully it will take care of this.
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I replaced the B+ filter today and added a ground to the monitor frame that was not connected to earth ground, still the same effect. When the monitor is in VGA mode in advmenu (prior to selecting a game) it shows a very slow ripple that moves from bottom to top. This monitor's doc says no isolation transformer is required (I have none) and I'm using a VGA breakout cable from ultimarc.
Lower res games have the same jitter as my linux boot sequence in the video.
Any ideas?
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All,
I need your help to correct the issue that you can see in the video. I have recapped the monitor with a kit from Bob Roberts, and have replaced the B+ filter. I am showing the picture with the brightness turned up with no signal. No other devices are turned on in the proximity of the cabinet. The monitor does not have an isolation transformer installed (according to the WG doc, one is not needed.) I have added an earth ground to the monitor frame.
Additionally, I followed the troubleshooting guide and replaced: C115, Q205 and Q101 to address the 'jitter' in the earlier post. This manifests itself at lower resolutions, but at this point, I am willing to live with it. The video you see below shows similar results in VGA.
Bob R counseled that it is probably a signal problem (that is introducing AC noise) but I have eliminated that variable in this video and by adding earth ground to the monitor frame.
IMG_0000.mov (http://www.youtube.com/watch?v=X4nUbe-ql8o#)
Any help or suggestions are greatly appreciated :banghead:
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Can someone tell me if the power supply board pictured for the U3000 that i have is missing a large cap? I have seen other photos on this site and around the web that show the same PS with a cap. If you look closely at the picture, there is that white adhesive on the board bottom center. Could this be contributing to the problem?
Thanks,
Mark
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that cap is a crtical component .
without it , this SMPS is working too hard with lowered raw B+ ( likely 120v) should be around 150-170Vdc (USA)
so, cap should be somewhere between 220-680uf and a 200-400v rating
sure explains the 120hz humbar !!!!
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qrz,
Thanks for your insight and response. I am having a little bit of difficulty locating the right part matching off against the schematic, I will take a closer picture of the board once I pull it out again. Also - thanks for affirming that putting the cap in will eliminate the humbar.
Thanks!
Mark
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finally took the time to look ....
main filter cap - C105 is rated 470uF @ 400v
schematic : http://www.wellsgardner.com/pdf/Schematics/U3000_27_inch.pdf (http://www.wellsgardner.com/pdf/Schematics/U3000_27_inch.pdf)
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qrz,
THANK YOU! Can you take a look at the photo? I appreciate the link to the schematic, for the life of me I can't see C105 - if I read it right, the negative side of the cap should correspond to the side with the white adhesive?
Additionally, it looks like I'm missing C102 & C103? (.0022uf 100v) am I reading the schematic correctly?
Thanks,
Mark
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qrz,
Pulled the ps from the cabinet to take a closer look. Noticed that C102 & C103 solder holes are closed, and they have been jumpered to L101 to 3 & 4. I'm not sure if this is an 'undocumented' fix from WG or not, would appreciate any insight.
Additionally, I show C105 from your analysis up close, but am puzzled because I cannot find the board marked.
Pics attached show 1000 words. C102 is at the bottom of the black wire and C103 is above. I don't know how to interpret what the ceramic disc capacitors are doing, looks like 2x 250 and 1x 400 - not sure.
Thoughts?
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qrz,
I installed that large cap today, and the jitter and humbars were both gone!
I played with MAME for about 45 minutes and things looked great, although the monitor did shut itself off after a period of time (vertical then horizontal collapse) then dark screen. I'm not sure if this is a signal or not, I powered down then back up a few seconds later and things were fine. Maybe nothing, but definitely has never done that before.
THANK YOU FOR YOUR ANALYSIS and help with the PS.
Thanks,
Mark
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Make sure you've double checked ALL solder joints on all three boards. (power supply, main, neckboard)
Especially after looking at the solder pads for that main filter cap....doesn't look like it was unsoldered initially.
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the 2 blue caps are for AC/noise suppression .
they usually are an intergrated resistor/capacitor device, and ul/csa listed .
i echo Kevin's suggestion to inspect the pcb . when in doubt , resolder .
once had a JVC receiver that the cust had taken to 2 previous shops for an intermittent .
symptom was it would randomly go dead . i couldn't find the problem initially either :badmood:
had it running off to the side on the main bench . happened to bump it, and it died with a flash from the pwr sup. hmmmm.
on close inspection, i discovered the solder had pulled away from the pad just enough to be an intermittent connection. ( main pwr xformer )
didn't look bad 'til pushed on it.
removed solder , clean pad . resolder = happy customer :)
and the rca ctc 177,8, 203 chassis's were a $ maker with all the cold joints they had ...
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qrz,
Thanks for the analysis on the blue caps. The monitor stayed on much longer today, entertaining my nephew. I did not shut down, so definitely intermittent. I'll remove that main cap, clean the pads and resolder.
Thanks fellas, this particular problem has had me scratching my head since November, I appreciate your help. I hope to return the favor someday. :cheers:
Thanks,
Mark