[url]https://www.badcaps.net/forum/showthread.php?t=32872[/url]
https://We miss you, Dave! Your expe...url]<br />
:)We miss you, Dave! Your expertise is need there:[url]https://www.badcaps.net/forum/showthread.php?t=32872[/url]
davmax
Badcaps Veteran
Last Activity: 09-19-2011, 05:56 PM
Joined: 12-02-2005
Location: Perth Western Australia
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We miss you, Dave! Your expertise is need there:
[url]https://www.badcaps.net/forum/showthread.php?t=32872[/url]
https://We miss you, Dave! Your expe...url]<br />
:)We miss you, Dave! Your expertise is need there:
[url]https://www.badcaps.net/forum/showthread.php?t=32872[/url]
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LG L1717 Monitor cap failure
I had a L1717 come in for repair. It is not an easy monitorto open up. First two screws must removed from what appears to be the stand mounting. These screws actually retain the front bezel, once removed the bezel can be prised off by first levering on the stand and lifting the back cover away from the bezel. The bezel can then be removed to gain access.
The cap problem. The power supply main filter cap 680uF 25V was blown apart. It was a a low grade (low ripple rating) Samxon. The rest of the Samxons gave no indication of stress. Apparently the main cap was not able to sustain the... -
Re: Fix for Benq FP737s 17" (Q7T3)
I feel I should add that to achieve the modification I describe you will need all the tools.
A soldering iron and self fluxing solder.
A PCB drill and bit 0.8 - 1 mm
A sharp knife to cut tracks. -
Re: Fix for Benq FP737s 17" (Q7T3)
In response to a request for the final modification details
I have made this easy by posting the final versions at an online album here: [url="http://picasaweb.google.com.au/davmax60/MonitorRepairs#"]http://picasaweb.google.com.au/davmax60/MonitorRepairs#[/url]
Use the full screen facility to see the detail.
Please note that there are two versions of current sense resistor, either a single resistor or two in parallel. Therefore the photo of the board underside shows the 0.082 ohm resistor version...Leave a comment:
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Re: Fix for Benq FP737s 17" (Q7T3)
Bobdee,
You are doing a great job helping out others in trouble. In general there are enough posted references to fix the FP737s in this thread. Basically this monitor has poor fault protection. The 3 amp fuse is not sufficient protection.
It is difficult to determine which of several failure modes causes the C5707s to blow. That is why I decided to create a fast protection circuit that would cover all overload current conditions. This circuit then enabled me to actually find out when fualts occurred because it is...Leave a comment:
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Re: Fix for Benq FP737s 17" (Q7T3)
The 2SC5707 is a robust transistor. It has excellent performance and ratings, it is ideal for the job. Just make sure new ones are used, do not install any used ones. Any transistor will fail if heavily stressed as happens under fault conditions. Unless the supreme effort is made to provide a fast protection circuit as I have earlier in this thread. This protects the transistors for all fault conditions. The original design does not have good fault protection.Leave a comment:
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Re: Fix for Benq FP737s 17" (Q7T3)
Yes well done afo. Just read thread today. Your original meter reading description indicated transistor failure. Glad you fixed it so quickly with parts kit.
Extending the ribbon cable is not a great idea as you no doubt concluded....Leave a comment:
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Re: Pentium 4 vent
Thanks Wizard
Those links are a great contribution. Makes facts crystal clear.Leave a comment:
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Re: Pentium 4 vent
True if not mounted. But I would suspect that if mounted with heatsink compound the vent would be sealed.Leave a comment:
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Re: Pentium 4 vent
Thanks for all contributions. I have learned something AND the CPU passes all diagnostics.Leave a comment:
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Re: Pentium 4 vent
Thanks. You right I have not seen this hole open before. All others are sealed. I would expect to be sealed whilst not installed to keep out ambient moisture.
So no suspicion of a cause.Leave a comment:
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Pentium 4 vent
I have just received a used P4 and the vent hole in the top of the case is open allowing atmosphere into the case. I normally see this hole sealed. It occurs to me that if the hole is open then excess pressure based on high temperature has occurred and popped the vent.
I have Googled many different ways to get some enlightenment on this vent but have found nothing of use.
Comment or input please. -
Re: Fix for Benq FP737s 17" (Q7T3)
Please note that the unmarked capacitor in the diagram is a 1uF polycarbonate. This cap can be seen in the top of board view at top right posted on 15th October. It can replace C770 in so doing cut the PCB track effectively to the right of this capacitor as shown on the circuit diagram, not where to cut is XXX.
I read somebody had problems with the mod. make sure you use the latest diagram posted 14th Oct and note the above.Last edited by davmax; 12-02-2008, 11:12 PM.Leave a comment:
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Re: Fix for Benq FP737s 17" (Q7T3)
Try these.
[url="http://cgi.ebay.com.au/LOT-OF-TWO-2-FU9024-FU9024N-D10PF_W0QQitemZ370103656745QQcmdZViewItemQQptZBI_Electronic_Components?hash=item370103656745&_trksid=p3286.m63.l1177"]http://cgi.ebay.com.au/LOT-OF-TWO-2-FU9024-FU9024N-D10PF_W0QQitemZ370103656745QQcmdZViewItemQQptZBI_Electronic_Components?hash=item370103656745&_trksid=p3286.m63.l1177[/url]
[url="http://cgi.ebay.com.au/KIT-4-PCS-2SC5707-C5707-FUSE-FU9024N-E172FPB-E173FPB_W0QQitemZ320301193969QQcmdZViewItemQQptZBI_Electroni...Leave a comment:
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Re: Fix for Benq FP737s 17" (Q7T3)
Yes Wragie you have described the poor quality of the PCB of the lamp inverter circuit. Certainly great care is required when reworking this board.Leave a comment:
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Re: Fix for Benq FP737s 17" (Q7T3)
Hi Jacknewboy.
Good to see you were successful. A few items for future reference.
1. This is a good source for all the components you need: [url="http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=320301193969"]http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=320301193969[/url] I see that this auction keeps renewing.
2. The 2SC5707 is a bipolar transistor. The black ones in the link above and the MOSFETs are the blue ones....Leave a comment:
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Re: Dell E172fpb
Do the TIP3055s get hot? Usually they do and are not a good or recommended replacment type. If the originals were 5707s they are not hard to get on eBay and not expensive.Leave a comment:
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Re: Fix for Benq FP737s 17" (Q7T3)
Did you resolder all the inverter transformer connections? It sounds as thoughthe 5707s are gone again. There are claims that the resoldering will enable a permanent fix. However as you have seen I have implemented the current limit system on three monitors with no further failures. This method catches all heavy overcurrents FAST (10usec).Leave a comment:
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Re: Bad dell LCD screen
Seems that you have a backlight failure. This requires some skill to dismantle and then check the back light inverter electronics. Sometimes you can be lucky and only have to replace a small fuse.
So to check it out it must be opened up, if you feel up to it. Then post some photos of the electronics boards. You also need to identify the model number of the Dell monitor if you need help, too many versions around.Leave a comment:
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Re: Fix for Benq FP737s 17" (Q7T3)
I forgot to advise that if the FU9024N (Q805) is burned up this is unusual and will most likely mean other components have failed. Normally the correct micro fuse would prevent this problem. I wonder if someone used an incorrect replacement fuse!!!...Leave a comment:
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