Another white screen Duo issue.

[Desh]

I played around again tonight.  First I started by using a plastic pick to go around every chip on the board pin by pin while I powered on and off to see if I could get the bios to boot again.  I also picked and prodded all over the board, wiggled and prodded every cap, vias freakin' everything.  I couldn't get the bios back just the blank screen (usually white, sometimes red or purple).

I went back to my desk and decided to check continuity again from 6270 to 6280, 6260 and VRAM chips.  This time I was very careful and easy when touching the pins.  I was hoping this would prevent me from "accidentally" fixing the problem.  I then checked each pin with the logic probe to make sure everything matched up.  Below is my worksheet



Since everything checked out OK I powered it up again and low and behold the damn bios booted.  Now, since CD bios is back again I figured I would try and boot a disc again.  Even with the door switch pushed it, it still displayed the "close door" message.  I checked and the switch closes.  I even checked from the little transistor to a far away via on the other side of the switch and opened an closed it.  WTF!  I am now adding issues.  It makes me wonder if the solder bridge I removed was there for this issue.  I have to look into that issue further.  Below is a picture of the solder bridge I removed.



Since I got frustrated with messing with the CD I decided to verify good connection to all hu slot solder pads.  That is all good.  I then soldered the TG connector back in and tested a hu card game.  Hu card game only brings up white (or sometimes red or purple) screen.  If I remove the card it will boot bios.  I have tried multiple games.  I even thoroughly re-cleaned the slot (I had cleaned it previously).  Then I wanted to verify there isn't a bent or broken pin I couldn't see in the slot so I put a card in as far as I could with the card pins still slightly exposed and tested continuity for card pin to slot pin.  That also checked out just fine. 

I guess I should re-check all outgoing pins on 6270 again with a game inserted and see if there are any changes.  I don't know, I'm starting to pull my hair out with this thing... it's starting to inch it's way closer to the scrap pile.

[blueraven]

Cool thanks for the notes and photo. This helps having a visual aid.

It's possible that the solder blob was there for a reason, to ground something like the CD assembly. I'm guessing your photo angle is from the underside of the board, right near the angle of the board where the CD drive is?

On the other side of the board what is the number for the 8-pin chip the blob was grounding? (i.e. G506 or something). If figure out what that numbered circuit does, it can be deduced whether or not the bloc needed to be there. If the problem gets worse, its always good to take a few steps backward.

i didnt question the supply, as he is working multiple units

That's what I figured, steve. Thanks for confirming that.

[Desh]

The solder bridge wasn't on a chip.  It was between two pins of the white connector for the CD drive.  My three other Duo boards did not have this.

[blueraven]

The solder bridge wasn't on a chip.  It was between two pins of the white connector for the CD drive.  My three other Duo boards did not have this.

Yeah, unless I'm totally mistaken that not supposed to be there. Maybe that was the reason that the previous owner got rid of it... Had a crossed circuit in the CD assembly as a result of the blob.

[thesteve]

the close lid msg is a good thing, as it means the cd system responded where it hadnt before
the issue could be a bad ic520 (remove it and try card)

[Desh]

Removed IC520.  HuCard games still do not boot.  It's the same white or sometimes red or purple screen.  No CD bios either which I assume is due to removing IC520.  I also pulled up two pads when removing 520.  I just ordered a small hot air gun.  F doing SMD the hard way anymore.

[thesteve]

ok well if 520 is good, then you could likely get intermittent card boots as well
removing it disconnects the cd system

[Desh]

ok well if 520 is good, then you could likely get intermittent card boots as well
removing it disconnects the cd system

I am going to wait until my hot air gun comes in and harvest a known good 520 from a parts board.  That should give me enough of a break on this thing.

[blueraven]

Yeah, don't get caught in a gumption trap. Best to walk away if you're getting frustrated. Also, don't worry about the lifted pads, they can always be traced back to a via or trace with a little x-acto knife scraping and a tiny bit of flux.

One question, did you get the readings from IC 520 before pulling the chip? Would have been good for comparison. I should be able to pull these from a working unit for you if you just removed it.

[Desh]

Yeah, don't get caught in a gumption trap. Best to walk away if you're getting frustrated. Also, don't worry about the lifted pads, they can always be traced back to a via or trace with a little x-acto knife scraping and a tiny bit of flux.

One question, did you get the readings from IC 520 before pulling the chip? Would have been good for comparison. I should be able to pull these from a working unit for you if you just removed it.

I didn't take any readings unfortunately.  It should be easy to repair the lifted pads as they both go directly to the Hu slot.

[Desh]

I've taken a long enough break from this project.  Played with it a bit today and now hu cards are loading WITHOUT IC 520 installed.  I believe thesteve is right.  I plan to swap over a known good IC 520 from a donor board tonight and see if this thing will finally be fixed.

[Desh]

Replaced IC 520.  Card games still work and I can access save ram etc.  The screen still shows the "close door" message.  Even though the switch tests fine I jumpered the connections anyway and still had no change.  I also bridged the 2 connector contacts that I had removed a bridge from since the "close door" error seem to pop up after I removed it.  That also didn't work.  I traced one side of the door switch circuit all the way back to a bank of smd resistors and I believe there is a bad via from there to a large ic on the top of the board (I don't remember the number I'll double check when I go back to it).  So that's where I'm at, still no concrete answers. 

I will also add that I thoroughly enjoy my little heat gun.  It's awesome.  It will help me get a couple of these dead TG boards that I believe have bad CPUs going now that I can easily work with surface mount stuff.

[thesteve]

Both sides of the switch go to the NEC chip between the two Sony ones