I need a PCB whisperer..

[burgerkingdiamond]

I tried to test out my Gunbird board on my new Blast City tonight and it's acting quite strange.

The board works fine when it's lying horizontally, but if I tilt it either forward/back or side to side more than about 30 or so degrees the video cuts out to some flashing vertical color bars and I hear a faint kind of static coming from monitor. It's so weird because it's very precise. The video will cut out at the same angle of rotation pretty much every time.

This is inconvenient since the board needs to be vertical to go inside the cab.

Sometimes when I rotate the board back to the horizontal the picture is still out and I have to jiggle and jostle it some to get it working again.

The board is in pretty pristine shape. It's very clean and I haven't been able to spot anything suspicious or any bad joints.

I don't know what anyone could really tell me other than to look for dry joints, but I'm hoping that maybe someone knowledgeable about the specific hardware can help me zero in on a particular area because there are a million chips to check.

[emphatic]

Sounds like a solder joint glitch + gravity pulling that loose part out of place? Do you have a magnifying glass?

[burgerkingdiamond]

Sounds like a solder joint glitch + gravity pulling that loose part out of place? Do you have a magnifying glass?

no I don't think I have one.

I was thinking about rotating the board and then going to every chip and trying to push it in to try and zero in on the problem, because visually inspecting every joint would drive me mad I think.

If I just touch the black part I shouldn't be too worried about accidental static discharge right?

[emphatic]

If I just touch the black part I shouldn't be too worried about accidental static discharge right?

The black part?

[burgerkingdiamond]

If I just touch the black part I shouldn't be too worried about accidental static discharge right?

The black part?

sorry, I mean the black plastic body of the chips. As long as I don't touch the legs or anything metal I don't need to worry about static discharge. right?

[emphatic]

I don't think you need to worry, no.

[robivy64]

Reflow all surface mount chips, including MASK ROMs.

[Dave_K.]

Another thing to check (may not be the problem) is the JAMMA connector being loose or having pins not making full contact. I have one cab with a very loose connector, probably because its been used so much the pins inside don't have as much tension anymore.

[burgerkingdiamond]

Dave K

no the jamma connector is fine and every other game I've tested has worked. It's definitely the board.

Robby

I don't like playing Gunbird near enough to attempt that. I'm going to get a magnifying glass and do some inspecting I guess.

[PC Engine Fan X!]

All else fails with you not being able to get that Gunbird PCB fixed, burgerkingdiamond, give Channelmaniac a ring via PM and he'll revive it.

PC Engine Fan X! ^_~

[burgerkingdiamond]

Reflow all surface mount chips, including MASK ROMs.

what's a mask rom?

can I reflow the entire board in my oven?

I hope that doesn't sound too dumb. I have a friend who used to buy rrod's 360's and reflow them in his oven in addition to other repairs. He apparently brought back a lot of dead 360's but I've never done it.

[system11]

Reflow all surface mount chips, including MASK ROMs.

what's a mask rom?

can I reflow the entire board in my oven?

I hope that doesn't sound too dumb. I have a friend who used to buy rrod's 360's and reflow them in his oven in addition to other repairs. He apparently brought back a lot of dead 360's but I've never done it.

No, don't even think about putting it in an oven.

Does it happen when the board is working and you wobble the cab loom slightly? I'd have to say Dave's suggestion sounds the most likely. I have never heard of a board that didn't work on its side, even with flex issues.

[channelmaniac]

I can do surface mount work if needed... I fixed a couple of pesky SPI boards that needed a lot of reflow work for robivy64/68k.

[burgerkingdiamond]

Reflow all surface mount chips, including MASK ROMs.

what's a mask rom?

can I reflow the entire board in my oven?

I hope that doesn't sound too dumb. I have a friend who used to buy rrod's 360's and reflow them in his oven in addition to other repairs. He apparently brought back a lot of dead 360's but I've never done it.

No, don't even think about putting it in an oven.

Does it happen when the board is working and you wobble the cab loom slightly? I'd have to say Dave's suggestion sounds the most likely. I have never heard of a board that didn't work on its side, even with flex issues.

No it doesn't seem to be realated to the loom at all. The connectino is very tight and there are no issues with other boards.

It's very bizarre, but it really seems to be strictly related to tilting the board. Unless it's flat or less than about 30 degrees from flat in any direction the video cuts out.

[burgerkingdiamond]

I can do surface mount work if needed... I fixed a couple of pesky SPI boards that needed a lot of reflow work for robivy64/68k.

I'm going to have to think about whether I want to spend any money to repair it. It's not one of my favorites and without an autofire circuit I won't be playing my Psykio games much anyway.