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Advice needed on repairing a motherboard

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Replacing the 2 transistors fixed the issue. Machine now works perfect and even the picture seems clearer! Thanks so much for this thread!!!!


Excellent! I'm sure it was more work getting the shielding off than it was replacing the bad transistors.


I'm really happy that this thread helped you get your Intellivision working again. Congrats!

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I have to ask, sincerely, is it worth repairing these old consoles? Why not just buy another one on e-Bay?

I'm not trying to be flippant, I just want to know. Of course, I have absolutely no electronics skills, so repairing would never be an option to me...


Troubleshooting and repairing these things is a game itself. Fixing one is highly satisfying. Learning new skills is fun too.


It is worth it as a fun hobby? Sure. A few times. But then it gets old. Is it worth it as a career? Oh hell no.

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  • 5 weeks later...

My Intellivision works.. requires a lot of cart wiggling and resets. Did a total cleanup and cap replacement, but looks like I'll need Q1 and Q2 as well. Now I get to try to source 2c parts in a post-Radio Shack world. Fry's is right next door to me, but their circuit section is a complete shame. Never restocked, perpetually out of everything anyone might need.



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Replaced. All is working. Fry's actually came through with two NTE159. I hope I never have to go down into the RF shield ever again...


Out of curiosity, can anyone explain the overheating mechanism for this circuit? Is it a failure of the transistors themselves, or is there a problem elsewhere causing them to run hot? The circuit looks like it runs on the 16v line direct from the transformer, clamped to a zener value. I imagine if the resistor/zener/ground failed, the clock circuit either wouldn't run at all, or the chips would have failed from the high voltage on their clock pins. Could there be a problem with the switching current on the base not fully driving the transistors completely on and off?

Edited by rmzalbar
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