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capamatic
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Last Activity: 09-20-2024, 01:43 PM
Joined: 04-19-2006
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  • capamatic
    replied to Gateway 900G frustration
    in Troubleshooting Computer Displays
    Re: Gateway 900G frustration

    Didn`t have to look far for the cause of the res. problem


    Looks like the recap put paid to the Vreg, assisted by a failing cap.



    Burned Vreg.


    Marked as A1SB then 51 rotated, doesn`t reveal much. Probably a manufacturers No. and impossible to trace, let alone find a replacement.

    So if anyone has a VBoard (200-100-GJ912W) or source for one, I`d appreciate a pointer.

    ...
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  • capamatic
    replied to Gateway 900G frustration
    in Troubleshooting Computer Displays
    Re: Gateway 900G frustration

    Thanks for the input,
    Sounds like it would be easier to source a replacement Video Board.
    Anyone have a spare?
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  • capamatic
    replied to Gateway 900G frustration
    in Troubleshooting Computer Displays
    Re: Gateway 900G frustration

    Good to hear there is a non-DVI version.
    Tried at the native res 1440 x 900 at all available freq`s, still bad.
    Disconnected the VGA and now the `Gateway` splash screen/`no video input` is garbled too !, initially it was perfect.
    Maybe the voltage supply to the Video Board is out of spec. ?
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  • capamatic
    replied to Gateway 900G frustration
    in Troubleshooting Computer Displays
    Re: Gateway 900G frustration

    Recaped the FPD1975W with Panny FC`s and monitor/backlight working perfectly....but...
    I have a resolution problem. At one point 1024x768 was fine but now at any setting I get a high pitched whinning and garbled image. I presume the video board is struggling somehow to display at the correct vertical and horizontal frequency.
    Googling this monitor shows it has both VGA and DVI, but not mine !...VGA only, strange.
    That being the case. I wonder if any of you chaps could confirm the Part No. of the video board.
    Thanks.
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  • capamatic
    replied to Gateway 900G frustration
    in Troubleshooting Computer Displays
    Re: Gateway 900G frustration

    I`ve got a stash of quality 1000`s , and better esr specs at that rating should prolong it`s life. C205 / C206 are in parallel and are under the most stress.
    Just wondered if anyone has done it.
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  • capamatic
    replied to Gateway 900G frustration
    in Troubleshooting Computer Displays
    Re: Gateway 900G frustration

    Just picked up one of these 900W`s and tested the offending caps.
    All Samxon caps, none visibly failing/failed.
    The 47uF read as 48uF and 0.15 esr (good, hhmmm)
    The 470uF`s read 0.05 esr (good) but all 4 were within a uF of 423uF.
    That`s exactly 10% reduced capacitance, so probably the fault cause.

    Has anyone subbed anything other than 470`s back in?
    Looking at the board, it`s easy to replace at least 2 of them with a 1000uF cap.
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  • capamatic
    replied to X-Power ATX 700W TD
    in Troubleshooting Power Supplies and Power Supply Design
    Re: X-Power ATX 700W TD

    Turns out it was a loading problem with the tester.
    Hooked up the SATA power cable and all voltages present and correct.

    Thanks to everyone who helped.
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  • capamatic
    replied to X-Power ATX 700W TD
    in Troubleshooting Power Supplies and Power Supply Design
    Re: X-Power ATX 700W TD

    Just found out that the -5V is optional on ATX12V 2.2 PSU`s. Used on legacy ISA cards apparently. So that sorts that one out.
    Now onto the missing +3.3V ??????
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  • capamatic
    replied to X-Power ATX 700W TD
    in Troubleshooting Power Supplies and Power Supply Design
    Re: X-Power ATX 700W TD

    Having decided the Welltrend IC was faulty, I decided to canibalise this one, and use it as spares on the second (also dead unit).
    This one had a blown fuse, a quick poke around revealed the input bridge rectifier to be shorted. Swapped it from the 1st unit and also the fuse.
    Switched on and life !
    Well, of sorts. I hooked it up to a little PSU tester (LED`s for the various Voltages) and all ok except no +3.3 and -5 .
    Just wondering if this points to something common ?
    Maybe the tester isn`t loading these rails ?
    ...
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  • capamatic
    replied to X-Power 600-TD again
    in Troubleshooting Power Supplies and Power Supply Design
    Re: X-Power 600-TD again

    Perhaps you could monitor pin 5 and 6 (V33 and V5 respectively) before a load is applied , then after.

    I was thinking of removing the IC from the 700-TW, and breadboarding it. If I fed it with the right voltages, it should indicate wether it`s faulty or not.
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  • capamatic
    replied to X-Power 600-TD again
    in Troubleshooting Power Supplies and Power Supply Design
    Re: X-Power 600-TD again

    If the WT7510 is anything like most others in the series, then VCC can be as low as 4V.
    The 7510 is a hard datasheet to find, beyond the 1-pager that is.
    The WT7514 has a max VCC of 5.5V

    Keep us posted.
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  • capamatic
    replied to X-Power 600-TD again
    in Troubleshooting Power Supplies and Power Supply Design
    Re: X-Power 600-TD again

    Any update on the 600 TD ?

    Was it the diode ? Did you manage to test the voltages `round the Welltrend ?

    I`ve pulled the 700 TW apart, everything tests OK. I`m convinced these Welltrend devices are faulty. Only course of action is to hard-power it on. Provided the output voltages are within regulation, then this would seal it.
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  • capamatic
    replied to Cheap Supply
    in Troubleshooting Power Supplies and Power Supply Design
    Re: Cheap Supply

    Get the datasheet of your monitoring/protection IC. If the `FPOB` pin is connected to the Opto, then the PSU starts because you have effectively disabled the output fault protection signal. It`s hard-powered on.
    You should be careful that your voltages etc are OK, as your PSU is now not fault protected.
    Consequently, if your outputs are OK, then you have a faulty protection IC or Opto.
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  • capamatic
    replied to X-Power ATX 700W TD
    in Troubleshooting Power Supplies and Power Supply Design
    Re: X-Power ATX 700W TD

    Thanks.
    I`ve been through all the diodes and all tested ok in situ.
    I`ll run through them again to be sure.
    The decoupling caps to the Welltrend IC were also fine out of cct.
    Did find a ceramic cap with its lead touching a link, but was connected on the solder side anyway.
    I`m still of the opinion the Welltrend IC is the major suspect.
    There is a small daughter-board with the PFC cct (2 smd IC`s) which might cause problems, but I dont think it would cause no-start.
    Is there a method to test if the output is...
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  • capamatic
    replied to X-Power ATX 700W TD
    in Troubleshooting Power Supplies and Power Supply Design
    Re: X-Power ATX 700W TD

    Update :-

    Desoldered the secondary heatsink
    6 Schottky rectifiers, 3 different types (30A) tested OK.
    Next step, solder it back up and test around the WT7517-164 chip.
    If it turns out to be this chip, could be a problem locating spares.
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  • capamatic
    replied to X-Power 600-TD again
    in Troubleshooting Power Supplies and Power Supply Design
    Re: X-Power 600-TD again

    Hi,

    Don`t know if the 600TD has the same riser-board as my 700TW, but the protection chip is similar.
    Anyway, have just ESR`d the two Teapo ESK caps on it - 100uf 25V.
    One of them is 0.5 Ohm, the other 1.1 Ohm.
    I suppose these are supply decoupling caps for the chips but are general purpose and may be causing some supply instability, enough to cause no-start ?
    I`ve not yet changed them so can`t comment on a fix, but am hopeful.
    Seems strange to use a GP Cap on a major chip, albeit 105C.
    Worth testing...
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  • capamatic
    replied to X-Power ATX 700W TD
    in Troubleshooting Power Supplies and Power Supply Design
    Re: X-Power ATX 700W TD

    OK, found some time to investigate further.
    I have +5V on the standby (purple) wire, no voltage elswhere on the ATX connector.
    Desoldered the primary heatsink, checked the FETs and diode - OK
    Checked the small value (100uf 25V) caps around the PWM chip, the ESR of these is 0.1 - seems strangely low
    The power resistor has a strange colour code BLACK,BLUE,SILVER,GOLD,GREEN ??
    Upon power-up, the unit sometimes crackles for a second then nothing (protection?)
    Primary side seems OK, ESR`d the caps, continuity OK, may ring...
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  • capamatic
    replied to X-Power ATX 700W TD
    in Troubleshooting Power Supplies and Power Supply Design
    Re: X-Power ATX 700W TD

    Thanks for the tips
    I`ll check them out and post back.
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    Leave a comment:

  • capamatic
    started a topic X-Power ATX 700W TD
    in Troubleshooting Power Supplies and Power Supply Design

    X-Power ATX 700W TD

    Hi,
    Wonder if anyone can help me with this ?
    Acquired 2 of these units, both dead. Loaded with a couple of DVD Drives and shorted the PS-ON pin, not even the fan spun up.
    They seem completely new, no signs of cap failure (mostly Teapo, Suscon)
    No obvious board damage nor component failure, internal fuse OK.
    As both units have similar symptoms, methinks common failure. DOA ?
    I struggle a little without schematics and repairing PSU`s is new to me.
    Would greatly appreciate pointing in the right direction.
    Many thanks....
    See more | Go to post
  • capamatic
    replied to A Look at Caps for Indonesia Market
    in General Capacitor Questions & Issues
    Re: A Look at Caps for Indonesia Market

    Always intersting to see `real` ESR values on new Caps.
    The Panasonic FJ 2200uf, Chemicon KZG 1500uf 6.3v and Nichicon HE would have me thinking the Cap had shorted.
    It`s getting to a stage where we need a fourth digit on the Bob Parker ESR Meter !
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