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[Trevante]

Got a 1.6 xbox here that was softmodded, had a 300GB HDD in it. The HDD has since been removed and now it has no HDD, and I couldn't get an eeprom backup from it. There's no video, but the sound works just fine. I've tried a regular composite cable and a component cable, same results with both.

Any ideas what may be wrong or what I could do to fix it?

[DarkMatter]

Check my reply post in the following thread:
http://forums.xbox-s...howtopic=577014
Regards,
DarkMatter

[Trevante]

Thanks for the reply. I'm not exactly the greatest when it comes to hardware problems on this scale. How exactly would I test for continuity? Just place the multimeter probes on either side of the chip? I'm  gonna go get a multimeter and try.

Also, looking, at the mobo, it seems my L4A4 might located in a different place. I'll try and show it better when I get back from the store.

[Trevante]

Thanks palmmann, I figured out the whole multimeter thing.



Mine is similar to that picture, but the red chip labeled L4A4 in the pic is actually L4A1 on my mobo. Not sure if it makes a difference, because it still seems that the red chip is where there is no continuity.

The 3 blue chips (excuse my kindergarten-like terminology) all gave values of 39 mV (I think that's the right unit), while the L4A1 (red chip) only gave 2 mV, so I'm guessing that's where the break in the circuit is.

Now, onto the fix...in the thread Darkmatter linked to, he said it can be fixed by bridging a thin piece of wire across it. Now, my assumption is that he means connect one of the blue chips to the red chips in order to close the circuit, but I want to make sure I'm correct before I go and mess up the xbox even more.

Thanks.

[DarkMatter]

QUOTE

Mine is similar to that picture, but the red chip labeled L4A4 in the pic is actually L4A1 on my mobo.

Your correct. The diagram I made had a typo error. Here's a revamped picture:



Your's may look different, but they are the same.
Just solder a thin piece of wire across the inductor as shown in the picture.
Please let us know how you get on.
Regards,
DarkMatter

[Trevante]

Thanks for the reply.

Soldered the wire across L4A1, no difference in continuity, still no video.

Checked for continuity again, and now L4A2 has a 3mV reading, while L4A3 and L4A4 have a reading of 76 mV.

I soldered another wire across L4A2, no difference.

Any idea what might be wrong? What could have caused the sudden loss of continuity on L4A2?

EDIT: Ok, now it seems that all 4 chips are dead... the continuity reads 1 mV on all of them. I'm guessing I might have somehow fried them while soldering. Is there any way to fix this?

[DarkMatter]

QUOTE

Ok, now it seems that all 4 chips are dead... the continuity reads 1 mV on all of them. I'm guessing I might have somehow fried them while soldering.

Somehow I don't think your using your multimeter correctly.
Your meter should be set to read low ohms. You should see a setting like 200 ohms (the ohms may be shown as the Omega symbol).
Best to read the manual that you got with your meter.
All the components locations marked: L4A1, L4A2, L4A3 and L4A4 should read zero ohms, or something very close to zero.
The one you should be concerned with is L4A1. The others don't concern composite output.
Please recheck and let us know what you find.
Regards,
DarkMatter

[Trevante]

Checked all 4 chips...they all have a resistance of about 1.4 ohm, although L4A4 sometimes jumped up to 76 ohms.

On my working Xbox (1.1 I believe), the L4A1 has a resistance of 1.4 ohms, but then L4A2-L4A4 have a resistance of 74-76 ohms.

Don't know if it makes a difference, but for a large part of the testing, I was using a component cable. I did switch to a composite cable yesterday though, with the same results.

[DarkMatter]

QUOTE

Checked all 4 chips...they all have a resistance of about 1.4 ohm, although L4A4 sometimes jumped up to 76 ohms.

Around 1.4 ohms is about right, but wouldn't be the exact resistance. The error is due to most digital multimeters not being able to read low resistances acurately. So no worries in that department.
The 76 ohms your reading is also correct. Actual reading should be 75 ohms, which is the correct input impeadance. But as I've already said, most multimeters don't have great acuracy, plus component values are rarely spot on.
I'm strongly suspecting that your Xcalibur Video Processor IC has been damaged, especially since shorting L4A1 hasn't helped. Unfortunately the only way to determine if it is the IC, is to replace it with a known good one. But very few people would attempt such a repair, due to the difficulty, as well as having the repair tools required to do the job without causing any heat damage.
Might be best to write-off your motherboard and obtain a second-hand unit from Llamma, E-Bay etc.
Sorry about that, but I've run out of ideas on how to proceed futher.  
Regards,
DarkMatter

[Trevante]

Thanks a lot for your time and effort.

As far as the xbox, I'm not too worried since I got it for free (everything minus HDD   ), so I'll put it in the BST or on eBay later on. Thanks again.

[DarkMatter]

QUOTE

Thanks a lot for your time and effort.

Your most welcome.  

Please check the following, as I've done a little more homework on this problem today:
http://jansforums.jc...c.php?p=141#141
Please let me know what readings you get. Thanx in advance.
Regards,
DarkMatter