Thread
Quadra 700 issue
Depends on the circuit those caps are in.
Yes tantalum capacitors short, BUT.. you need to remove them to double verify.
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.
This caps is 47uf 6 volts? It should be replaced?
The fact that moving the mouse left that artifacting is a clear indication it's a digital issue.
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.
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.
some weren't even that much discolored... and a black tantalum cap you would never know.
i personally don't like them.
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)
As long as capacitance is the same, voltage rating shouldn't matter too much?
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Buddy, that's a shorted tant. Read my post again to see that was one of the failure modes.
Is correct to use caps with more voltage? (6,3v>16v)
I already I have them... and new 6,3v 47uf case "D" is hard to find
I already I have them... and new 6,3v 47uf case "D" is hard to find
iv had them be massively out of SPEC and not shorted BUDDY>
Using cap with a higher voltage will not be a problem as long as the capacitance is the same
If you can't make it work, you can always find a Quadra 800 board, That's what I did(although there was'nt anything wrong with my Q700) and my Q700 board is in my IIvx
Why are we so determined that it's the caps and not the VRAM? It's a heck of a lot easier to pop in a NuBus video card than it is to replace caps.
The problem is not only the video output, power switch random not work and is impossible to power off (I disconnect the power cord). Change caps is a easy operation end low cost, if not work I change the logic board or buy nubus card
I'm getting ready to throw a Q650 mb in a q700 case, and see what happens. project for later in the week.
The only issue you'll run into is that you'll have to repin the speaker. Everything else is in the same place, although, I wish I knew how to change the gestalt via hardware back to Q700 so that way nobody can really tell unless you open er up.
Awesome man!!... yeah and its cool the 650 can accept 512 megs of ram .. that is ridiculous.
I wanted to do it (650 logic board), but then I thought that I want to original.
I have replaced the caps but the problem remain the same... Now I have a nubus card and with this the video output is perfect! I need to replace the onboard vram?
Other problem is the power switch, why my mac not poweroff when i push the back button? It only restart... I only test it without disks, mac need system installed for correct power management? Keyboard on/off not work, and power on take log time (long press of power switch).
Other problem is the power switch, why my mac not poweroff when i push the back button? It only restart... I only test it without disks, mac need system installed for correct power management? Keyboard on/off not work, and power on take log time (long press of power switch).
Yeah, a system would likely help. The switch isn't twisted into "auto reboot" position, is it?
Another problem 
Quadra start with System 7.1 disk utility, but no hdd... try to initialize and hang at verifying. I try to format same drive with powermac and all good, move the drive to quadra and not mount in desktop, I launch Apple Hd sc setup press test and pop-up "problems writing data to drive". Internal or external, same issue. Why?????????
Is the original 120mb apple hdd.
I use generic system 7.1, quadra have a special disks?
Quadra start with System 7.1 disk utility, but no hdd... try to initialize and hang at verifying. I try to format same drive with powermac and all good, move the drive to quadra and not mount in desktop, I launch Apple Hd sc setup press test and pop-up "problems writing data to drive". Internal or external, same issue. Why?????????
Is the original 120mb apple hdd.
I use generic system 7.1, quadra have a special disks?
I have buy a new motherboard! Power switch problem solved, scsi problem solved... video problem remains the same! However very similar!
I have buy a motherboard with the same defect of my old one? No problem, I have a nubus card and work pefect, but.........
I have buy a motherboard with the same defect of my old one? No problem, I have a nubus card and work pefect, but.........
yeah just keep the nubus video card in there… or change the vram with a hot air reflow station.
or i wonder if you remove it, it will still work from the VRAM slots.?? never tried… might work.
I'd like to know, I not have hot air station, but I'm sure that is the solution ... I find it!
maybe something like this... they are rather cheap these days. http://www.ebay.com/itm/852D-2-in-1-Soldering-Re-Work-Station-Solder-Iron-SMD-Hot-Air-Gun-5-Nozzles-NEW-/272042976768?hash=item3f57066600:g:9ZYAAOSwwbdWQe6O
I have old motherboard for experiments... if I remove 5v pin from vram chip, I not disable it? If this method work, is easy to find damaged chips!
no, just remove the vram as they are bad.
you can try to run it w/o the vram, it will either work or not.
if it works cool..
if it doesn't work then replace the vram from a bad board or a VRAM simm.
you can try to run it w/o the vram, it will either work or not.
if it works cool..
if it doesn't work then replace the vram from a bad board or a VRAM simm.