Apple II+ flashing/intermittent display

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Apple II+ flashing/intermittent display

Hello-

I'm a new member ,and new to the world of old Apples so please excuse my ignorance when it comes to any questions or comments I ask or make. :)

Being interested in old computers, I recently picked up a couple II+'s  from a surplus dealer to see if I could learn something new.

I dont have a apple monitor, so I connected it to an old monitor that has a composite input and it seems to function.

The problem I am experiencing is that the displayed output is intermittently turning on and off. Its almost is if there is a bad connection or something.

Turns on for 1/2 sec then off for one, back on for one, off for two, etc.

I have messed with the composite connection and that doesnt seem to change anything.

Funny thing is both II+'s do the exact same thing.

 

I have tried searching the forum and cannot find any posts relating to this problem, so any advice you can give to a complete noob as to how to troubleshoot this

would be greatly appreciated.

I dont think its a powersupply issue since the computer stays on, just the display cuts in and out.

Thank you in advance!!

 

 

 

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Have you tried a different

Have you tried a different RCA cable?  Have you tried the monitor with a different composite video source?  It seems less likely that both computers are broken in the exact same way than something is wrong with the monitor and/or cable.

 

 

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Agreed that it seems unlikely

Agreed that it seems unlikely, but I have tried this monitor and cable with other sources and everything is good.

I guess I should have mentioned that in my orignal post.

 

 

 

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You could try

You might try adjusting the Apple's video level but most likely the monitor is not happy with the Apple signal. You could also try running it through another device like a VHS machine and see if that works.

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jeffmazur may be correct that

jeffmazur may be correct that the monitor may not like the Apple II signal.  To say that that Woz played fast and loose with the NTSC signals would be a generous statement.  There are a lot of monitors that refuse to generate a good picture from the Apple II video out at all.

 

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Very good thoughts.  I also

Very good thoughts.  I also have a IIe that works fine with that monitor, but that does not mean the II+'s will react the same.

 

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Check those RCA Jacks too!

While it might seem unlikely that 2 Apple II+'s exhibit the same problem, it is not as unlikely as it first seems.

 

The reason I say that is because a fairly common failing with the old II+ and //e computers is the RCA jack that is soldered to the motherboard. Over the years of people inserting and removing the RCA cables (usually twisting the cable in the process) the solder joints have a habit of coming loose or the actual jack itself can be damaged and require repair/replacement.

 

If you jiggle the cable near the RCA jack, do you see the display go on/off/change? If so, it may be a problem with the RCA jack itself. It's a simple test worth checking.

 

Cheers,

Mike

 

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Thanks for the input Mike.

Thanks for the input Mike.

I did try exactly what you suggested, and it doesnt make a difference.

Has anyone ever tried one of those COMPOSITE -> VGA converters to connect an old Apple to a modern monitor/tv?

If I cannot locate a peroid correct apple monitor, I may try that next, or the VCR trick.

 

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A better option might be to

A better option might be to get a modern expansion card to ouput VGA, rather than try to convert the composite signal

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kellyh wrote:Has anyone ever

kellyh wrote:

Has anyone ever tried one of those COMPOSITE -> VGA converters to connect an old Apple to a modern monitor/tv?

Those are hit or miss.  The problem is that the Apple II doesn't really output a standard composite NTSC signal.  The best solution is to just get an Apple monitor-- they aren't that expensive and are pretty common.

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grimakis wrote:A better

grimakis wrote:

A better option might be to get a modern expansion card to ouput VGA, rather than try to convert the composite signal

That's possible-- the card you want is called VidHD from Blue Shift.  https://www.callapple.org/vidhd/

I don't know if they have any in stock, as they are built in small lots.  It's also much more expensive than a used Apple monitor.

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