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KnobsNSwitches

LC 575 board (in Color Classic) - funky vertical lines

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I took a chance on an unknown condition LC 575 logic board for upgrading my Color Classic. 

The good news: it boots! The bad news: it looks like this: 

 

 

(don't mind the error message on the screen. I haven't moved over the right system enabler for the 575 board in the color classic yet. I just wanted to test booting yet)

I don't see any obvious capacitor goo on the board, but I did give it a rinse in distilled water and a scrub with a toothbrush and the screen still looks like that. Any ideas of what could be causing the picture?

IMG_5701.JPG

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22 minutes ago, beachycove said:

Reseat the 575 vram simm, or try another.

There are 2 installed (I need to verify if they need to be in pairs), I have reseated and swapped their locations. I don't have any spares, I'll need to seek some out.

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A few years ago, I had one bad vram simm in a 575 logic board (installed in a CC too) that caused very similar anomalies. It’s possible that vram could explain your troubles. The nice thing in this case is that all vram is easily replaceable, as there is none soldered onboard. The bad thing is that you need additional vram Simms to test the possible fault.

 

You have no other machine from which to borrow some?

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6 minutes ago, beachycove said:

You are relying on the ResEdit hack, right?

Yes. 

 

7 minutes ago, beachycove said:

A few years ago, I had one bad vram simm in a 575 logic board (installed in a CC too) that caused very similar anomalies. It’s possible that vram could explain your troubles. The nice thing in this case is that all vram is easily replaceable, as there is none soldered onboard. The bad thing is that you need additional vram Simms to test the possible fault.

 

You have no other machine from which to borrow some?

Sadly, no, the CC is my only vintage desktop. I have some 30 pin SIMMs and several PowerBooks, but nothing else to borrow some from.

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The resedit hack is all about the screen, so make sure that's done right before going further. I somehow missed the enabler reference in the original post, so maybe be sure the software is right first. 

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Just an update to this thread.

I purchased some new VRAM from memoryx.com, but the symptoms persist. 

(I should note, the lines are visible on screen before booting goes anywhere, on the happy mac, 'welcome to macintosh' etc. )

 

I recapped the board, just in case, if nothing else to practice my soldering, but still have the same issue. I must keep digging. 

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I've a similar issue with my LC575 board, is the Mac "usable" and does it boot to desktop?  If so, still VRAM but could be a bad trace on the connectors themselves.  I've not recapped mine yet.

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On 3/30/2018 at 9:10 AM, KnobsNSwitches said:

I took a chance on an unknown condition LC 575 logic board for upgrading my Color Classic. 

The good news: it boots! The bad news: it looks like this: 

 

 

(don't mind the error message on the screen. I haven't moved over the right system enabler for the 575 board in the color classic yet. I just wanted to test booting yet)

I don't see any obvious capacitor goo on the board, but I did give it a rinse in distilled water and a scrub with a toothbrush and the screen still looks like that. Any ideas of what could be causing the picture?

IMG_5701.JPG
 

 

That is hot!! I do not know why..but I start picturing Apple // when I saw this picture.

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On 5/16/2018 at 12:43 AM, Byrd said:

I've a similar issue with my LC575 board, is the Mac "usable" and does it boot to desktop?  If so, still VRAM but could be a bad trace on the connectors themselves.  I've not recapped mine yet.

I missed this response somehow. Yes, it is "usable" in that it does boot, but it's really hard to see any thing. ;-)

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