3115 -b no cpu v core ,!!!! i did a compare excelsheet pls chk attach file

[turbo]

finally turbo here .. 820-3115 board, no cpu v-core.. fun running high speed, i have a compare excel sheet for u7400 chip in put , pls chk... attach file

it had water damage, i had to did connect t29 circuit.

cant attach file it says invalid xlx!!

 

[turbo]

pin	g00d		no good
1	0.51		12.35	CPUIMVP_TONB
2	0		0.072
3	0.829		0.002
4	0.056		0.035
5	0		0
6	0.104		0
7	0		0
8	0		0
9	0	in	0
10	0	in	0
11	5	in	5
12	0.123		0.001
13	0.145		0.177
14	4.7		4.7
15	0		0
16	0		0
17	0		0
18	0		0
19	5	in	5
20	0		0
21	1.03	in	0.95
22	1.03	in	1.05
23	1.01	in	0.829
24	3.3		0.046
25	5.85		4.73
26	0.829		0
27	1.1		0
28	4		0
29	5		5
30	0		0
31	0		0
32	0.85		0
33	0.81		0
34	5.8		4.7
35	2		2
36	2		2
37	0.3		0.38
38	0		0
39	4.4		4.56
40	4.5		4.59
41	0.819		0
42	0.821		0
43	0.81		0
44	0.81		0
45	5		5
46	5	in	5
47	3.3	in	3.33
48	0.61		12.39

 

[larossmann]

R7403 and R7402 measure what? Is the trace from R7403 and R7402 to U7400 intact? It can look intact but not have continuity as part of it goes under the chip. Check carefully!

 

[turbo]

R7403 and R7402 is 182 and 151, line is intact

 

[turbo]

can you find out anything from that value chart for all pin

 

[turbo]

louis just found out L7630 = 1.05v, but L7510 , l7520 and L7550 no voltage

 

[dukefawks]

What area was water damaged? Corrosion under/around PCH will also cause no Vcore. U7400 needs to be enabled through SMBUS, so PCH and CPU VCCIO need to be running.

 

[larossmann]

If R7402 & R7403 are good it will be corrosion under U1800. Some kester 951 and a gentle reflow of U1800 - GENTLE, the PCH is a very easy to kill chip with heat, will do.

I go over it here. https://www.youtube.com/watch?v=pQHW...&nohtml5=False The video also includes the logic & intuition that one would follow to come to this conclusion, so you not only get the answer, but how you'd find the answer yourself next time!

It is very easy to kill the PCH. I see the balls melt for 5 seconds and I turn off the heater and turn on the fans to be on the safe side.

duke knows more about this circuit than I do, so follow his advice over mine. My guess would be on corrosion you can't see under U1800. Ultrasonic won't fix this, heat and flux.

 

[turbo]

thanks for quick reply , u7400 might be bad too? even thou i replaced this from a good known board, i ordered some u7400, ill reflow pch after changing u7400... is this a good idea?

 

[larossmann]

U 7400 usually only goes bad when one of the high side mosfets for the CPU vcore Buck converter shorts. Otherwise it is fine.