Re: Troubleshooting Viewsonic vx2235wm
Hey guys, the monitor I repaired seems to be showing a new symptom. I'll try to explain as best I can.
The monitor runs consistantly good while connected via VGA (analog). However, when running on the DVI (digital) connection, the screen occassionally goes black for 2-3 seconds, and then comes back on. Sometimes when it comes back on, there are red pixels across portions of the screen, and the monitor will reset itself again after a few seconds.
I've only noticed this issue while playing games on the computer,...
Kostamojen
Member
Last Activity: 07-08-2011, 06:02 PM
Joined: 06-16-2011
Location: Orange County, California
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Troubleshooting Panasonic CT-25G6E
Just today my Panasonic ct-25g6e tube tv died. The screen is black, except when I change the input source I get a line at the middle of the screen. I've attached a photo of the screen when changing the input source. As a side note, this tv spent several years in a beach side home, so it was probably subjected to higher than average moisture levels. Any idea what could be wrong?... -
Re: Troubleshooting Viewsonic vx2235wm
Managed to find a fast blow fuse with the proper amperage and voltage at Frys. They didn't have a pigtail fuse, so I got a little creative with the soldering iron and some discarded leads from the cap replacement. I've attached a photo of the custom fuse. Installed everything and the monitor fired up like a beauty! Thank you to everyone who contributed to this thread. You were all a great help. And I got a 22" widescreen monitor for $20 in parts. I think I'm hooked!...Leave a comment:
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Re: Troubleshooting Viewsonic vx2235wm
Time for a little education on fuses:
Found a fuse on Digikey that might work. [url]http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=F3298-ND[/url]
Looks like the same amp and voltage rating. Can't tell if its glass or if that even matters. Can anyone tell me if that fuse is viable for this application?
Thanks again.Re: Troubleshooting Viewsonic vx2235...F3298-ND[/url]Leave a comment:
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Re: Troubleshooting Viewsonic vx2235wm
Radio Shack is coming up short. They have fuses with the amps and voltage. But they don't have a bracket that will work with the board. Recommendations?...Last edited by Kostamojen; 07-01-2011, 02:57 PM.Leave a comment:
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Re: Troubleshooting Viewsonic vx2235wm
Glass fuse is PGU manufact. and labeled F3.15A 250V. Radio Shack for replacement? Or should I look somewhere else? Anything special I should be aware of?Leave a comment:
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Re: Troubleshooting Viewsonic vx2235wm
ICs look good. No measurements under 20 ohms. Anything else I should do before trying to find a replacement for the glass fuse?Leave a comment:
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Re: Troubleshooting Viewsonic vx2235wm
Hey Bill, got those directions on checking the inverter drivers? Much appreciated....Leave a comment:
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Re: Troubleshooting Viewsonic vx2235wm
PlainBill, your help has been invaluable! Thanks so much! But, I'm still looking for a solution to this fuse. Do you have to de-solder to remove the old one? and any suggestions for finding a replacement?...Leave a comment:
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Re: Troubleshooting Viewsonic vx2235wm
the fuse does NOT show a short in either polarity direction. Sounds like a bad fuse? Where can i find a replacement? and do you have to de-solder the fuse to remove it?Leave a comment:
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Re: Troubleshooting Viewsonic vx2235wm
When I test the fuse in question, the ohms shoots to 0 briefly, then drops to the left side of the meter....Leave a comment:
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Re: Troubleshooting Viewsonic vx2235wm
GOOD NEWS! during my last inspection of the circuit board, I noticed a solder bridge near the capacitor labeled "I" (the one that was obviously shorted). After removing the solder bridge, the short is gone. I re-assembled the monitor and now get power light indicators (blue when a PC is connected, orange sleep-mode when no PC is connected). However, there is no picture. I shined a flashlight on the screen, and can see a ghost image of the signal being sent from the PC.Leave a comment:
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Re: Troubleshooting Viewsonic vx2235wm
Ran the test as laid out by PlainBill. I started by calibrating the MM, per instructions. The results are shown in the attached photos. One photo shows the results, the other photo shows the lettering key (NOTE: picture take prior to cap replacement, but the same lettering was used).
Ohms readings under 50 were investigated, however, only one time did the two readings match (at 0 ohms for cap "I"). In all other cases, the needle stayed at the far left side or would briefly pop to the 200-40 ohms range, then return to...Leave a comment:
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Re: Troubleshooting Viewsonic vx2235wm
I tried powering up the monitor after replacing the caps, and I got no power lights or screen power (see my first post from June 25, 2011). That's why I'm trying to troubleshoot the board. I'm assuming that I messed something up while doing the repair (created a short, or something). It appears that the only caps that are showing a reading above 0 ohms are CE108 and CE109. would that tell you anything? or do I need to go pickup a new digital multimeter?...Leave a comment:
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Re: Troubleshooting Viewsonic vx2235wm
I thought I might have a difficult time describing the readings I'm getting (since I myself don't really know what I'm looking at). So I've taken some photos of the test results. Hopefully you can interpret the results for me.
The first photo was taken with the MM in it's default state (only the ground probe connected). Each consecutive photo shows the MM reading with the positive (red) probe touching the positive lead of each of the new caps.
I got different results from different caps, so I'm guessing there is...Leave a comment:
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Re: Troubleshooting Viewsonic vx2235wm
Maybe I'm doing the measuring wrong. Do I touch the black and red leads to the cap leads sticking out the bottom of the board? How do the polarities on the mm leads need to match up to +/- leads of the cap? Please be specific as I'm pretty new to this. Thanks....Leave a comment:
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Re: Troubleshooting Viewsonic vx2235wm
Finally had some time to hit this thing with the multimeter. Only one cap indicated a possible short (>3 ohms). It's the 220uf 25v cap at CE109? I also just remembered that this is where my hand slipped and the solder tip dragged across a couple circuits. It looked superficial to me, I hope I didn't kill the board. I'm posting a picture of the area so you can look at it. It looks like a faint white line. Please tell me i don't destroy it....Leave a comment:
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Re: Troubleshooting Viewsonic vx2235wm
I've uploaded some pictures so you can check my solder work. Let me know if you see anything questionable.
I've borrowed a multimeter, but, to be honest I don't really know what I'm doing here. I'd appreciate an explaination of the process of testing the voltages.
Should the board be connected to the rest of the monitor components when I test the voltages? What setting do I use on the multimeter? Which lead (black/red) do I touch where?
Sorry for being such a noob. I'm very interested in learning...Leave a comment:
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Re: Troubleshooting Viewsonic vx2235wm
1) I did create a solder bridge at one point while connecting the new caps, but I corrected the problem before the monitor was tested. And I don't think there are any solder blobs, but I'll check again.
2)All connectors were securely connected and double checked. No screws that appear to be shorting anything.
3) I was VERY careful to observe polarity on the board. I created a schematic before removing the old caps, and followed it carefully. Even double checked everything before the test.
...Leave a comment:
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Re: Troubleshooting Viewsonic vx2235wm
Hey guys. Well got my caps in and did the surgery. Think I did a decent job with the soldering, but I'm getting no power-on lights or picture. What should I test next? Thanks.Leave a comment:
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