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820-3209 keeps burning current sensing resistors
- Thread starter Narek
- Start date
Do NOT do that again, as no reason.
"Pin 27 - 0,619v
Pin 28 - 0,579v"
You still have a problem with R7051/52, or traces.
"Pin 27 - 0,619v
Pin 28 - 0,579v"
You still have a problem with R7051/52, or traces.
Did you power up the board now?
Not yet, after I replaced ISL and resistors with new ones I had to leave my office. I’ll power it up on Monday and report. Something tells me, that they will blow again... Thank you for your support, I really appreciate it. I wish you good weekend, will get back to this on Monday ?
Run it on battery, until drain about 50%.
Then check if battery is charging.
Then check if battery is charging.
"I've removed F7040 and applied 8,56v on pin 2, board is powering on, fan is spinning, CPU gets warm"
I was thinking that works on battery alone...
Post PPBUS_G3H voltage on battery alone and bat+charger.
I was thinking that works on battery alone...
Post PPBUS_G3H voltage on battery alone and bat+charger.
I've applied direct voltage with power supply then
With battery only connected PPBUS is 7,98v, battery + charger jumps 7,5v-8,59v.
I've replaced R7086 and it blew up again (Q7080, Q7085 replaced too)
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"I've replaced R7086 and it blew up again"
Impossible, if you soldered correct 330K value.
Be sure to have correct resistors on board.
Impossible, if you soldered correct 330K value.
Be sure to have correct resistors on board.
Considering the worst scenario, applying 20V on 330K resistor, means 0.06mA (60 microampers).
Do you really thing that resistor can get blown from such reason (1.2mW)???
Do you really thing that resistor can get blown from such reason (1.2mW)???
Yes, you are completely correct, I don't argue with that. I just post here what is happening on this board. I put perfectly measuring 330K resistor, triple check it before plugging charger in. After I plug it in nothing happens. I disconnect charger, check that resistor and it's OL.... I've done it 2 more times now. every time putting 330k resistor..
Remove C7085 and replace R7085/86, Q7080 and U7000.
Everything done and checked triple before connecting charger. Board has green/orange light, clicking every half second with quarter fan spin. With charger only PPBUS is 8,37v, with battery 7,99v, with both is jumping 8,17v-8,56v. Current sense is OK, U7000 pins 27/28 have 20,5ohm, 17/18 have 2,5 ohm.
R7086 was perfect 330K, after disconnecting charger it shows OL or 80K, after some time it's 330K again. This board is trolling me now...
R7086 was perfect 330K, after disconnecting charger it shows OL or 80K, after some time it's 330K again. This board is trolling me now...
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