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Quadra 700 issue
Posted by: TheWhiteFalcon on 2015-10-29 05:49:41
I could be wrong but is your PRAM battery in backwards?
Posted by: marmotta on 2015-10-29 05:58:41
I could be wrong but is your PRAM battery in backwards?
Is correct, in the picture at bottom is "+" in the top "-"
Posted by: uniserver on 2015-10-29 06:16:40
i am wondering if the onboard vram has gone bad...    I think your best bet is try to hit ebay and follow what an other had mentioned,  Try a Nubus Video card.  you should be able to pick one up for decent low price.     The picture you posted is ok,  but the quality is not good enough where i can tell if there are legs of I/C's that are bent over or touching.  I wonder if mike Techknight wants to throw in his feedback?
Posted by: marmotta on 2015-10-29 06:51:36
i am wondering if the onboard vram has gone bad...    I think your best bet is try to hit ebay and follow what an other had mentioned,  Try a Nubus Video card.  you should be able to pick one up for decent low price.     The picture you posted is ok,  but the quality is not good enough where i can tell if there are legs of I/C's that are bent over or touching.  I wonder if mike Techknight wants to throw in his feedback?
This picture have best quality: http://discoremoto.cheapnet.it/apmarmotta/IMG_3327.jpg

The board is cleaned
Posted by: marmotta on 2015-10-29 09:04:40
This three caps are bad (with my tester)... is very close to RAMDAC and PowerSwitch
Posted by: olePigeon on 2015-10-29 11:34:47
Looks to have a lot of goop on there, too.  Could use a clean in general.
Posted by: marmotta on 2015-10-29 11:47:24
Looks to have a lot of goop on there, too.  Could use a clean in general.
I have used a "not dry" cleaner... later i have used a "dry cleaner"
Posted by: unity on 2015-10-29 12:22:10
Just use warm water and a gentle brush. I find paint brushes work really well. Shake water off and use compressed air or hairdryer to move water out from under chips. Then dry in an oven at 120 degrees F. Too hot is bad. Occasionally pull form oven and shake to get water out.

This is a great inexpensive method that I have used many, many times.
Posted by: techknight on 2015-10-29 13:57:01
You need a VRAM testing program, I wonder if one of the common diagnostic softwares out there could test it. Because the issue could be int he VRAM, but it could also be in the RAMDAC. 

Also those 3 caps being bad, highly unlikely, what meter? 
Posted by: marmotta on 2015-10-29 14:06:16
You need a VRAM testing program, I wonder if one of the common diagnostic softwares out there could test it. Because the issue could be int he VRAM, but it could also be in the RAMDAC. 

Also those 3 caps being bad, highly unlikely, what meter? 
With tester in continuity (ohm) good capacitor load and release energy, tester show a variable numbers. With this three bad capacitors my tester show only a fixed value of "0" or "0,15".

And my problems with powerswich is a confirmation (is not certainly vram related)
Posted by: unity on 2015-10-29 14:41:14
I thought caps can only be tested with an ESR meter unless removed.
Posted by: marmotta on 2015-10-29 15:08:37
I thought caps can only be tested with an ESR meter unless removed.
Yes is better, but if the cap is in continuity and not load energy is not normal...
Posted by: techknight on 2015-10-29 17:19:10
Depends on the circuit those caps are in. 

Yes tantalum capacitors short, BUT.. you need to remove them to double verify.
Posted by: marmotta on 2015-10-30 01:32:47
Depends on the circuit those caps are in. 

Yes tantalum capacitors short, BUT.. you need to remove them to double verify.
You are right... I have removed the caps from the PCB and now is not in short. In any case I order a new caps.
Posted by: marmotta on 2015-11-01 02:47:37
This caps is 47uf 6 volts? It should be replaced?
Posted by: CelGen on 2015-11-01 08:33:55
Try a different monitor and cable.
The fact that moving the mouse left that artifacting is a clear indication it's a digital issue.

there could be a dead tantalum. 

can you take some good quality pictures of your main board and maybe we can have a look and maybe spot something wrong?
Tantalums have two failure modes. Dead short or blown up. They don't gracefully drift out of spec and when they die they make it pretty obvious as you have discovered.

Keep all your VRAM pulled as you mentioned that it's happening with it removed. This narrows the fault down to bad onboard VRAM or a problem with the video chipset. If you can, find a copy of Snooper and run the VRAM test.
Posted by: uniserver on 2015-11-01 10:19:31
no you are wrong, i'v removed plenty of overheated tantalum caps that were no good BUDD.  

some weren't even that much discolored...  and a black tantalum cap you would never know.

i personally don't like them.
Posted by: marmotta on 2015-11-01 10:23:12
I wanna try to change black caps (see picture above), I have some yellow caps with 47uf 16v, they are fine? (the original is 47uf 6,3v)
Posted by: CC_333 on 2015-11-01 12:58:38
As long as capacitance is the same, voltage rating shouldn't matter too much?

c
Posted by: CelGen on 2015-11-01 19:54:02
no you are wrong, i'v removed plenty of overheated tantalum caps that were no good BUDD.  

some weren't even that much discolored...  and a black tantalum cap you would never know.
Buddy, that's a shorted tant. Read my post again to see that was one of the failure modes.
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