820-00165 PPBUS 15V

2click

Member
I have this board, no corrosion found, had a short on pp3v42, that is fixed now, but now ppbus_g3h is at 15.6v already changed Q7130 and U7100 no change...
 

2informaticos

Administrator
Staff member
Did you solder correct Q7130 in place?
Be sure all solders and traces are good there.
Check all resistors around U7100.

Please, do NOT quote an entire post, visible few centimeters above.
There was ONLY ONE question, no need to do that for your reply.
 

2click

Member
I´ve checked all traces, all are good, resoldered q7130, now I´m getting 3,6v at pin 1 of f7140 without the fuse...
 

2informaticos

Administrator
Staff member
Post basic voltages for U7100; pins 1, 2, 3, 6, 9, 12, 13, 14, 15, 17, 19, 20, 27.
Check R/C networks from pins 5, 7, 8.
Post exact resistance (ohm scale) between pins 17/18 and 27/28.
Keep F7140 removed for the moment.
 

2click

Member
U7100 Voltages:
1- 0v
2- 16.30v
3- 4.3v
6- 0v
9- .03v
12- 3.4v
13- 3.4v
14- 3.4v
15- 0.08
17- 3.34v
19- 5v
20- 5v
27- 16.1v

resistance between
17/18 - 3.6 ohm
27/28 - 20.3 ohm
 

2click

Member
just measured diode mode on pin 1 and 2 of f7140 (red probe ground, black on pins)
PIN 1- .138
PIN 2- .175
Checked big coils and there is one that has the same value that PIN 2 has: L7630, with red probe on ground .175, with black probe on ground .199
I don´t know what else to do to make PPBUS_G3H to come to life, please help!

EDIT: Got the PPBUS_G3H to work! it was pin 8 on Q7130 that wasn´t good. Now I have 8.60, but don´t want to put the fuse back yet. Is the L7630 value correct?
 
Last edited:

2click

Member
Changed Q7630, and still measuring .2ohms, checked L7630 to ground on ohm scale I get 230 ohms in diode mode red probe to ground I get .165 is that a short?
 

2click

Member
removed Q7630 and checked from L7630 to PIN 2 from F7140 im getting 3 Kohms and going up. Thanks for your patience, I know this is a delicate line and I don´t want to screw it up if it is not screwed yet...
 

2click

Member
resoldered Q7630 and getting 4 kohms from L7630 to PIN 2 F7140, hopefully that is good and I can go ahead and put in the fuse?
 

2click

Member
So I put the fuse back, connected it to the PSU and nothing... Q7630 shorted again...
Removed Q7630 and there is no short to ground on L7630. that is a good thing isn´t it?
 
Last edited:
Top