NeXT Megapixel Color 17 Repair

NeXT Computer, Inc. -> NeXT Black Hardware

Title: NeXT Megapixel Color 17 Repair
Post by: brooklyn on September 07, 2016, 10:59:30 PM
Hi, I have a NeXT 17" Color Megapixel display that was included with a nextstation I bought.  The monitor was sold as not working.

When I got home and tried it, I heard the CRT energize, but immediately some magic smoke escaped, so I quickly turned it off.

On disassembly I found some cooked components on what looks like the video out board.  See pictures.  I ordered replacement components to solder on, but I wonder if another issue caused these components to go out?

Any ideas?   :?:   Will update when I have a chance to replace the burnt components later this week.


Title: NeXT Megapixel Color 17 Repair
Post by: barcher174 on September 07, 2016, 11:24:49 PM
I think it's likely if you just replace those components and power it up you will blow the new ones as well. I have no idea as to the full purpose of this board, but as I see it, each signal (RGB) has a cloned set of circuitry. Knowing that you should be able to check the values and compare across the components even in circuit to get a general idea of what else could be failing. I would immediately suspect the electrolytic cap of drying out and shorting. Secondly I would be suspicious of those transistors, followed by the diodes.
Title: NeXT Megapixel Color 17 Repair
Post by: crispin on September 08, 2016, 12:47:45 PM
I believe NeXT sold two kinds of 17" monitors. One was a Sony and the other was Hatachi. The Hatachi monitors were horrible and failed frequently. I myself went through 2 of them in the 90s.
Title: NeXT Megapixel Color 17 Repair
Post by: brooklyn on September 13, 2016, 12:15:47 AM
I think it is an Italian monitor.  I replaced the damaged components and now the monitor turns on, however there is no horizontal or vertical sync.  It's either the video in board that I repaired earlier, or a problem on the deflection board.  I inspected both boards visually and there is nothing obvious.

Any tips?  Does anyone have any spare boards from Megapixel Color 17 monitors?



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Title: NeXT Megapixel Color 17 Repair
Post by: Rob Blessin Black Hole on September 13, 2016, 01:42:56 AM
Great effort , I sent you a PM. Best regards Rob

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