Forum: General Electronics Technical Discussion
Yesterday, 01:21 PM
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Replies: 7
Views: 88
Re: bad cap cause fuse to blow?
Ok, then it is a fault in the high voltage section, I mentioned the switches because it is a common problem with microwave ovens.
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Forum: General Electronics Technical Discussion
Yesterday, 11:46 AM
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Replies: 7
Views: 88
Re: bad cap cause fuse to blow?
You wont be able to check the diode with a regular multimeter unless the diode is dead short. it is a high voltage diode, it has several diode junctions stacked in series internally, the capacitor...
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Forum: Troubleshooting TVs and Video Sources
05-26-2022, 05:24 PM
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Replies: 17
Views: 346
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Forum: General Electronics Technical Discussion
05-26-2022, 05:06 PM
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Replies: 7
Views: 88
Re: bad cap cause fuse to blow?
In most cases when the fuse blows it is caused by a defective door switch. The primary interlock door switches is likely bad (stays closed) and when the interlock monitor switch closes it blows the...
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Forum: General Electronics Technical Discussion
05-26-2022, 10:12 AM
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Replies: 15
Views: 784
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Forum: Troubleshooting TVs and Video Sources
05-25-2022, 02:35 PM
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Replies: 7
Views: 753
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Forum: Troubleshooting Computer Displays
05-22-2022, 06:54 PM
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Replies: 24
Views: 2,711
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Forum: Troubleshooting TVs and Video Sources
05-21-2022, 06:37 PM
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Replies: 114
Views: 10,584
Re: Sharp LC-60SQ15U TV DPS-167CP - No power
What do you have in place for D7950? Maybe disconnect whatever is in there and see if the vcc comes up.
The ic's startup cell IS providing the initial 9volts, (at low current) so there can't be...
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Forum: Troubleshooting TVs and Video Sources
05-21-2022, 04:55 PM
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Replies: 5
Views: 129
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Forum: Troubleshooting TVs and Video Sources
05-21-2022, 04:45 PM
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Replies: 114
Views: 10,584
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Forum: Troubleshooting TVs and Video Sources
05-21-2022, 03:08 PM
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Replies: 114
Views: 10,584
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Forum: Troubleshooting Computer Displays
05-20-2022, 08:07 PM
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Replies: 24
Views: 2,711
Re: Benq BL3200PT with a cooked PSU.
Also check R651, it is a low value (likely under 1Ω). It is connected between the modfet source and the primary (hot) ground, if this resistor is open, the ic would have been damaged.
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Forum: Troubleshooting Computer Displays
05-20-2022, 08:01 PM
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Replies: 24
Views: 2,711
Re: Benq BL3200PT with a cooked PSU.
The components are connected between the ic's output and mosfet gate. You need a multimeter to check them to see if they are good or bad. as for the ic, it can't be tested but is likely bad.
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Forum: Troubleshooting Power Supplies and Power Supply Design
05-20-2022, 07:55 PM
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Replies: 8
Views: 147
Re: What is this part? (OG XBox Delta PSU)
Yes 102 would be a 1k pot, I suspect once you check it you will find it to be ok, Check between the two leads on the one side, then check between the single lead and each of the other leads, that...
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Forum: Troubleshooting Computer Displays
05-20-2022, 07:46 PM
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Replies: 24
Views: 2,711
Re: Benq BL3200PT with a cooked PSU.
Q651 is the main switching mosfet, if the pins were shorted, then the gate saw a very high voltage, so it likely destroyed the resistors and diodes in the gate circuit and also the driver ic located...
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Forum: Troubleshooting Power Supplies and Power Supply Design
05-20-2022, 07:02 PM
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Replies: 8
Views: 147
Re: What is this part? (OG XBox Delta PSU)
VR501 is the pot location, not it's value, check it with a meter or look for numbers printed on the pot. Are you sure it is bad, as I doubt it is burnt.
I see other pictures that have the same...
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Forum: Troubleshooting Computer Displays
05-20-2022, 05:11 PM
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Replies: 24
Views: 2,711
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Forum: Troubleshooting TVs and Video Sources
05-20-2022, 04:50 PM
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Replies: 114
Views: 10,584
Re: Sharp LC-60SQ15U TV DPS-167CP - No power
PC7904 is used to turn on Q7902 to supply vcc_on so it can be left out of circuit for now.
If you also remove pc7903 and D7908, pin 4 of ic7903 should be about 7volts, If it does not come up, try...
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Forum: Troubleshooting TVs and Video Sources
05-20-2022, 04:22 PM
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Replies: 114
Views: 10,584
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Forum: Troubleshooting TVs and Video Sources
05-20-2022, 04:16 PM
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Replies: 114
Views: 10,584
Re: Sharp LC-60SQ15U TV DPS-167CP - No power
Yes, check pins 1 & 4
The vcc voltage is initially supplied by the ic's internal startup cell which is bout 9volts, that part of the ic is working. When the power is first applied the internal...
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Forum: Troubleshooting TVs and Video Sources
05-20-2022, 03:50 PM
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Replies: 114
Views: 10,584
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Forum: Troubleshooting TVs and Video Sources
05-20-2022, 03:45 PM
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Replies: 114
Views: 10,584
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Forum: Troubleshooting TVs and Video Sources
05-20-2022, 03:33 PM
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Replies: 114
Views: 10,584
Re: Sharp LC-60SQ15U TV DPS-167CP - No power
WHY? because if that feedback winding is open circuit you will not get the boosted vcc voltage to make the ic work.
Look at the schematic, It's pins for this winding are 1&4, on your board they are...
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