Re: High resistance measurement
Good advice, buy a tester. A guy like edison would home brew a test. They didnt have digital meters 100 years ago.
johnfin
Senior Member
Last Activity: 11-06-2019, 11:36 AM
Joined: 10-22-2017
Location: tampa, fl
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High resistance measurement
Any old school way i can check a 600meg ohm resistor. Maybe like putting a frequency through it and using a scope? -
Re: Magnavox DRV power supply SMPS
Well since you have not answered any PM's or emails in the last 179 posts I wont hold my breath or waste my time with you anymore, phony baloney.
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THE ENDLeave a comment:
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Re: Magnavox DRV power supply SMPS
So your mighty 1200 chip is not so mighty. I removed the additional caps, 22k resistor in tact, still no voltage so I replaced the 1200 and guess what, 10volts on pins 6-4. I removed the chip so that I dont blow thru a dozen of these figuring things out. Back to square one.Leave a comment:
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Re: Magnavox DRV power supply SMPS
22K back
10uf added to 10uf in parallel
results
2106 = 157vdc 148vdc
2108 = zero
pins 4&6 = .06vdc
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added 22uf to existing 20uf caps in paralled
same but pins 4&6 went up to .1vdcLeave a comment:
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Re: Magnavox DRV power supply SMPS
R2106 = 157/154vdc
R2108 = zero both sides
was taken to - side of main cap.Leave a comment:
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Re: Magnavox DRV power supply SMPS
you were right, didnt work. Paralleled a 18k to get 9900ohms and pins 4-6 read 7.14vdc. Whats next.Leave a comment:
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Re: Magnavox DRV power supply SMPS
the 22k is what you called for and what it is. needs to be lowered i guess. any thoughts.Leave a comment:
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Re: Magnavox DRV power supply SMPS
ok, you threw me a curve. I was looking at r2106 on the board. they are all disconnected. the 22k (its good)is new and connected to pin 8. What resistance and wattage should I try?Leave a comment:
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Re: Magnavox DRV power supply SMPS
4&6 of the 1200 means I went across them to get the voltage. =7vdc
R2101 is a HUGE ceramic resistor, ohms fine and measured each side to neg on main cap = 167vdc
R2106 is a smd, no real voltage measured from each side to neg on main cap
ohms fine
All resistors in series with 2106 ohm out fine.
So whats next?Leave a comment:
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Re: Magnavox DRV power supply SMPS
cap = 160vdc
fuse good (of course)
pins 6 and 4 of 1200 = 7vdc (yes replaced)
when measuring resistors, can I use neg of big cap for ground, then each side of resistors.
Frankenboard coming alive, right?Leave a comment:
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Re: Magnavox DRV power supply SMPS
Resistors came today. Installed .68ohm resistor and same results: no light and power is getting to board. Circuit breaker ok, power to board, resistor and mosfet new. No power at ouput. Whats the next test?Leave a comment:
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Re: Magnavox DRV power supply SMPS
So what could have taken down the BIG resistor? Would be good to know so it doesn't happen again. Bought parts, waiting....more down time.Leave a comment:
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Re: Magnavox DRV power supply SMPS
which type are flame proof and what wattage for these,?Leave a comment:
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Re: Magnavox DRV power supply SMPS
I have replaced that mosfet before I believe. I appears to be bad
2108 is open (hard to believe), need to check with analog meter
2101 ceramic whopper 9.9m
2106 smc .38m
so no light at all, tried in pitch black.
2108 is .68 ohms right? I need to buy one or find a 2 ohm and 1 ohm and put them in parallelLeave a comment:
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Re: Magnavox DRV power supply SMPS
Ok, before we dig in, I replaced the ncp1200 and replaced the mosfet with the one you mentioned before. Plugged it in and the light did not come on and no voltage at output. 120vac at input. So lets get from there and start measuring. Let me know where.Leave a comment:
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Re: Magnavox DRV power supply SMPS
Well it went up in smoke, or at least the ncp1200. Turned it on, light came on full brightness, then a pop and smoke. Chip was hot so I assume its bad. Any way to check it? I will triple check the wiring again.Leave a comment:
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Re: Magnavox DRV power supply SMPS
Any special output measuring points. Maybe somewhere on the high or low side after the transformer. I wouldn't want our modification results to be thrown off by something on the low sideLeave a comment:
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Re: Magnavox DRV power supply SMPS
So for our first test am I leaving Q2101 and R2234 as original?Leave a comment:
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Re: Magnavox DRV power supply SMPS
frankenboard...Leave a comment:
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