820-2530 ppbus .19 volts always stays green

shanenin

Member
I have an 820-2530 which is not turning on. I have 0.19 volts on ppbus with no short.

The adapter light turns green and never changes to orange, does that indicate anything in particular?

My only thought is isl6958, but I am not sure what enables I should be checking first
 
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2informaticos

Administrator
Staff member
Post some voltages for ISL6258 (U7000), pins 2, 3, 19, 20, 12, 1, 14, 9, 15.
Post exact resistance between pins 17/18 and 27/28.
 

shanenin

Member
thanks :)

of the 9 voltages you asked for I have 0v on all of them except 3.4v on pin 12 and 18.2v on pin 1

17/18 20.7 ohms
27/28 20.4 ohms

on a side not the steady green light is gone

edit added/

I do have a 10 ohm short on r7011 or pins 3 and 19 or the isl
 
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shanenin

Member
of the 9 voltages (2, 3, 19, 20, 12, 1, 14, 9, 15) you asked for I have 0v on all of them except 3.4v on pin 12 and 18.2v on pin 1

is this what you are asking?
 

shanenin

Member
I did switch the isl, and the short is gone between pins 3 and 19. The only voltage change is I now have 4.35v at pin 3. I still have the same voltages at 12 and 1. Do you still need me to check for shorts/lows on the other isl pins?
 

shanenin

Member
thanks. I will try that tomorrow. Does that diode change the voltage or just work as a one-way valve?
 
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shanenin

Member
Well, this was interesting. I switched out the diode and had a good ppbus of 12.6v. I think I still had other issues as it was not pulling hardly any amps. I was wondering about the missing green light on the charger and noticed one of the power pins was pushed in. So I grabbed an after marker charger which we have used for ages(we have gotten rid of all of them, expect this one was still laying around) to see if I would get the green light back, which I did. Then I was taking voltages for all of the isl6258 pins for future reference. Then I noticed it was no longer working anymore. D7010 is bad again. While measuring it I noticed the after marker charger is giving 18.9 volts, could this have been what caused it or just coincidence? I am leaning towards coincidence since something had to have killed D7010 before and it is likely the same thing. Should I track another diode down and try again?

edit added//
for replacement diodes, what things should I be looking for in the schematics so I can check donor boards?
 
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2informaticos

Administrator
Staff member
After D7010 is changed, don't power up the board before check for short or low value to ground on some pins of U7000; especially pin 2!!!
That diode is not critical; original is Schottky, but normal Si should work too.
 

shanenin

Member
is SI mean a silicone diode? Is the difference having a slightly greater voltage drop? Could you give any suggestions on what to search for in the schematic in regards to finding a replacement?
 
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shanenin

Member
what do you mean it is not critical? Do you mean a different type of diode with a 100ma limit can be used or I can just use a jumper(probably not).
 

shanenin

Member
I did put a big fat diode on there. Pin 2 is not shorted. I have a short on pin 17.
 
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shanenin

Member
I am embarrassed. I am not sure what I did, but 17 is not shorted :-( Sorry. I think I may have read M(ohm) as plain ohms
 
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