Garbled video or sad Mac 00000014 / 0000CD38 post recap

[Elemenoh]

I recapped a new-to-me backlit Portable and am using a Portable Battery Eliminator by @Androda.

It will either display random garbage on the screen, just gray screen with backlight, sad Mac 00000014 / 0000CD38 with no backlight or nothing at all.

My understanding is that 00000014 / 0000CD38 means power manager couldn't start up.

I pulled and checked the MOSFETs at Q1, Q15, Q16 and Q20. All of them are short drain to source even after shorting gate and drain with a finger.

If all of them are bad, I'm concerned other stuff might be fried too. Maybe someone tried to boot it up before recap and took some things out?

I have to order the MOSFETs but am curious if someone here knows what other components I should check if the MOSFETs are all blown.

 

[Elemenoh]

I found one end of C15 was shorted to a nearby trace. I fixed that up but the symptom is the same.

 

[JDW]

Below is a photo of the 5126 motherboard by @Branchus , and we can see C15 is the hybrid / power manager area in the lower left:

When I had my 5126 recapped, there was a fair amount of trace damage in the area of C24, C15 and C26. Meaning, some traces had to be rebuilt with overlaid wire, and at least one thru-hole was rotted out and bodge wire had to be applied to the bottom side of the motherboard. I suspect the same to be true in your case too, which means a lot of beeper-mode checking of that area (top and bottom) with your multi-meter.

If your board has been recapped, it could be you won't be able to see some trace damage under your new caps. In my case, the caps were bad and the person who recapped it was able to see all the damage because the old caps needed to be removed anyway. He used an ultrasonic cleaner first (after bad caps were removed), to ensure all the cap juice was removed from the board before any further work on it began. The fact he had an ultrasonic cleaner and I didn't was a big reason I chose this person to recap my board. I figured the cleaner could do a better job than my hand, toothbrush and 100% IPA ever could.

 

[SuperSVGA]

Error 14 is unfortunately the very first test/error that you can get, so it's hard to say what else might not be working, but getting to that point means many things are working at least.

Since you're not always getting that far I would suspect some sort of power issue.

Start with the most important voltages first, the 1.2V reference and the +5V. If possible watch it for a bit to make sure it doesn't fluctuate about.

1.2V on pin 8 of U2L:

+5V on pin 2 of Q16:

 

[Elemenoh]

Thanks for the helpful tips!

 

[Androda]

Although the M5120 and M5126 are different, I believe the connections between Power Manager chip and VIA are the same. Check that all the data bits and PMACK/PMREQ traces are solid using the available Portable schematics.

The power manager chip itself also needs a good 5v supply, which the schematic ought to help with. And verify the A/D line on power manager chip, it's possible your backlit's "hybrid area" (what I call the backlit power regulator) is sending too much voltage to that particular pin. The M5120 design allows that A/D feedback line to go way too high when the hybrid malfunctions, which I think is a cause of power manager chip failures.

 

[Elemenoh]

I found a rotten trace and via under an almost rotten off leg of RP201. I haven't patched it up yet, but suspect this is the issue.

 

[Elemenoh]

BTW, the current Datasheet for 4861P doesn't seem to decode the part used on RP201 which is a Bourns 4861P-E41-000 and I can't find that part online anywhere. If you know what the spec for that resistor pack is supposed to be, please chime in.

 

[SuperSVGA]

That would be the trace connecting the 1.2V reference to pretty much everything else.

Here's what I have documented for RP201: