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Classic II Blank Screen


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So I recently bought a classic II of of ebay, and it had the condition where it showed lines with static around them. I heard that a way you could fix this problem would be to wash the board, so I soaked the board in water for about 3 hours. I then left it for about 20 hours underneath a light source. I also removed the rom chips and put them back. Now when I turn the computer on I only get fan/hdd spinning noises, and this clicking noise, which happens about once per second. I do not get any startup ping, or screen output. What should I do? I have tried disconnecting the drives molex cable, but that doesn't help anything.

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I am not sure where the hell you got directions like that for cleaning the board, but never do that again please.

 

Anyway, make sure your ROMS are set correctly. The sockets are longer than the chips. You want to configure for 128k & 256k most likely. That sets the chips in a way that they are closer to the RAM in the socket.

 

However, the clicking may be an analog issue.

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I am not sure where the hell you got directions like that for cleaning the board, but never do that again please.

 

Anyway, make sure your ROMS are set correctly. The sockets are longer than the chips. You want to configure for 128k & 256k most likely. That sets the chips in a way that they are closer to the RAM in the socket.

 

However, the clicking may be an analog issue.

 

It look like the sockets and the chips have the same number of pins, 16 per side. Also I heard that the clicking can be a problem with the PSU turning on and off rapidly. If that is the case, what should I do?

 

Also, C33 has beige stuff around it, how should I clean that? Or should I get the entire board recapped?

 

 

 

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C33 on the logic board or analog board? Either way the board with that cap needs to be recapped if it is leaking.

 

Most Classic IIs can be brought back to life 90% of the time with a recap, it is the easiest of boards to resurrect - though there is a hard to replace cap on between ports on the back-right hand side of the machine.

 

Once the logic board is recapped and brought back to life, the analog board should be recapped as well. Also check for cracked solder joints along the connectors.

 

How many ROM Chips goes it have - 2 or 4?

Edited by Elfen
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C33 on the logic board or analog board? Either way the board with that cap needs to be recapped if it is leaking.

 

Most Classic IIs can be brought back to life 90% of the time with a recap, it is the easiest of boards to resurrect - though there is a hard to replace cap on between ports on the back-right hand side of the machine.

 

Once the logic board is recapped and brought back to life, the analog board should be recapped as well. Also check for cracked solder joints along the connectors.

 

How many ROM Chips goes it have - 2 or 4?

 

 

It has 2 rom chips, and it is SMT cap on the back of the logic board.

 

Also I listened around and it seems like the clicking sound is coming from the flyback transformer

Edited by bman12three4
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Now I am also getting the same screen that I saw when I powered it on for the first time. I'm starting to think that there is just a problem with the logic board just because the analog board is doing less of the clicky thing and more of the display-e thing, and more often.

 

Is the best option still to do a recap?

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Like I said, recapping the board will bring 90% of all dead Classic IIs with your symptoms. It did for many others including me:

https://68kmla.org/forums/index.php?/topic/23800-semi-successful-recap-on-classic-ii/

 

Did you use acetone when you washed the board?

 

Yes, recapping is the only option to repair 90% of all Classic II Boards. More work maybe needed if there is damage to the board (like mine and a couple others since the sound does not work but that's no biggie for me).

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Okay, sorry for all of the updates,

 

 

 

 

 

 

Elfen, on 17 Apr 2015 - 7:01 PM, said:

Like I said, recapping the board will bring 90% of all dead Classic IIs with your symptoms. It did for many others including me:

https://68kmla.org/forums/index.php?/topic/23800-semi-successful-recap-on-classic-ii/

 

Did you use acetone when you washed the board?

 

Yes, recapping is the only option to repair 90% of all Classic II Boards. More work maybe needed if there is damage to the board (like mine and a couple others since the sound does not work but that's no biggie for me).

 

 

 

 

 

 

I did not use acetone, just water. I can borrow some nail-polish remover, that is the same thing right?

 

Also I am kind of stupid and I touched the screen while it was doing its clicky thing, and I could definitely feel where my other hand was touching my leg being zapped. I won't do that anymore, that's for sure.

Edited by bman12three4
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Nail polish remover is a little weaker than "Pure Acetone" but it will work when needed. Fill up a glass or ceramic Pie Pan and dunk the board in it, slough it about a bit for a few minutes and then take it out. Then with a hair dryer set to warm, blow out the board until it is dry and make sure to blow air under the chips. This will get rid of the leaky cap residue and possible shorts and other issues it creates. It will also stop the caps from corroding the board any further.

 

At this point you can recap the board or sent it to Uniserver for the recap. It will work if he does it because he will also repair other issues with the board. And he charges a very low price for parts and labor and he guarantees his work!

 

Congrats on your first static shock - this happens to all Mac Classics (from the 128 to Color Classis and LC500/5000 series) as static electricity builds up on the crt tube and touching it the static charge goes to you and then to where ever it can go from you. It is absolutely normal when you touch the screen. They never mention that on the Mac Owner Manual - LOL!

 

While the board is being recapped, clean up the case, mouse and keyboard, so when you get it back, you will have a clean Mac to put it into. Where the fan is inside the case, run the vacuum to get rid of the dust bunnies inside - they don't rent so out they must go!

 

Good luck on your problem and post up what happens!

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Acetone is to stop the cap goo from rotting the board any further. It is not going to help fix the machine because the caps themselves are either open or shorted out and to fix it they need to be replaced.

 

As is, the caps are still leaking and that goo is eating away at the board wires, breaking them. The more they break, the more work needs to fix it. Putting the board in acetone stops the goo from doing any further damage. That is why it must be done.

 

When the caps are replaced in the recapping process, the board is restored to near normal and most of the time will boot up on the first go. Most of the time. Question is, how much damage the cap goo did to the board and needs to be repaired? Most of the time this is minimal, and for Classic II easy to do. If this was a LC475, lets say... it becomes a much harder job to do.

Edited by Elfen
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Acetone is to stop the cap goo from rotting the board any further. It is not going to help fix the machine because the caps themselves are either open or shorted out and to fix it they need to be replaced.

 

As is, the caps are still leaking and that goo is eating away at the board wires, breaking them. The more they break, the more work needs to fix it. Putting the board in acetone stops the goo from doing any further damage. That is why it must be done.

 

When the caps are replaced in the recapping process, the board is restored to near normal and most of the time will boot up on the first go. Most of the time. Question is, how much damage the cap goo did to the board and needs to be repaired? Most of the time this is minimal, and for Classic II easy to do. If this was a LC475, lets say... it becomes a much harder job to do.

 

 

So soak in acetone and then send to get recapped?

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Well dont let it soak for 3 hours. You *might* not have much of a board left after. I never use acetone to clean my boards because I know it can easily dissolve certain plastics. Or make them very soft. But I can not say what plastics are used for the boards and never wanted to test drive it. Not saying its bad to use it, its not, just be smart.

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