| Electronics > Repair |
| NOCO GB70 repair help |
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| AN86:
Sorry my bad, it was late and kids and wife was crazy around me so i write it wrong. i ment works on 2.nd statment as it works that it wants to start override, i thought that button works when i press it and it goes in override mode, but nothing after happen. Leds flash but no real output. Ill check what you suggested and post again. Sorry for confusion |
| AN86:
--- Quote from: jerryk on October 17, 2024, 12:58:23 am --- Remember the battery balance plug and the relay plug are the same. Don't mix those two up ;) --- End quote --- You mean they are not the same? or Im confused now :-DD I did measure with all plugs dissconected. 4.52Mohms, and with JST relay plug connected it said 0.8ohms. |
| jerryk:
With all plugs disconnected: Edit to add: Measure the resistance across D17 ( this should have already been done per reply #32) Measure the resistance between the red and white wire on the relay pair. Then measure the resistance across the two parallel bus bars on the relays. Measure the resistance across the following resistors - R74, R75, R76, R77, R79. Just list the values if you like. Then measure the resistance between all the pins on Q14. I'm not concerned about specific values. Two of your measurements should fall under .5 M ohms range and one around 10k. Anything in the low ohms range would indicate an issue. Jerry |
| AN86:
R74 - 3.194 kohm R75 - 3.195 kohm R76 - 10.07 kohm R77 - 4.7 kohm R79 - 246.9 kohm Q14 - 2 pin next to the R74 and R75 are at 3.195 kohm Others are 0.531 mohm and 238.1 kohm. |
| jerryk:
Even though this is in circuit testing they should read sort of close to the value on the resistor with the exception of R79. This is about how it should read. This can vary between multimeters and switching the probe polarity can effect the reading. R74 - 4.7 kohm R75 - 10 kohm R76 - 10 kohm R77 - 4.7 kohm R79 - 245 kohm Are you saying 0.531 milliohms here? Or did you mean megaohms? --- Quote from: AN86 on October 22, 2024, 08:06:11 pm ---Others are 0.531 mohm and 238.1 kohm. --- End quote --- Again with all plugs disconnected - Did you test for resistance across D17? You can also do a diode test in circuit here too. If you can confirm the milliohms vs megaohm question. If the answer is megaohms AND D17 tests as a functioning diode the next test is to plug all plugs back in, turn the unit on, engage the override/boost to you get the progressive leds flashing. At that point test the voltage at the test point next to R74. It should read 3.3V. The underlying assumption here is that when you engage the override/boost button the battery status leds flash progressively but there is no click at the main relays and no transfer of power to the clamps. Pin 11 on your MCU controls the base of Q14 thru R74. When Q14 turns on it the powers Q15 that drives the main relay coils. We are just trying to see why this circuit is not functioning correctly. Keep in mind that this could still travel full circle back to the MCU but there is a possibility that Q14 has an issue or D17 might be shorted. Jerry |
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