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Just wondering if these parts commonly go on a intv model 1.  Mine works but the board is black.  It's the two black parts.  Just want to know in case I have to order parts in the future.

 

20190909_222500.jpg

20190909_222308.jpg

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It is interesting as I've worked on many intellivision model 1 units and I've honestly never seen any with that cooked PCB near those transistors myself. Although I've seen plenty of pics from others that have. It makes me wonder if the ones I've serviced are newer and didn't have this issue with the heat on those transistors or if the ones I've come across were powered on in use in better ventilation during their lives?

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There's a further possible issue with PCBs too:  Once they start burning like that, the fiberglass material becomes conductive, making the board itself into a resistor.  You can check that with multimeter probes, touching different areas within a burn to measure resistance.  If there's a reading that's significantly lower than infinity, the only possible remedy (other than replacing the board) is to cut out the burnt area and build a daughterboard with the parts that are supposed to go in that area.

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15 hours ago, mr_me said:

Yes those transistors have been known to fail.

How does this happen?  Where can i buy one?

10 hours ago, ChildOfCv said:

There's a further possible issue with PCBs too:  Once they start burning like that, the fiberglass material becomes conductive, making the board itself into a resistor.  You can check that with multimeter probes, touching different areas within a burn to measure resistance.  If there's a reading that's significantly lower than infinity, the only possible remedy (other than replacing the board) is to cut out the burnt area and build a daughterboard with the parts that are supposed to go in that 

Appears I caught it in time.  There is no major damage.

 

Edited by Polish.Gasoline

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14 hours ago, -^Cro§Bow^- said:

It is interesting as I've worked on many intellivision model 1 units and I've honestly never seen any with that cooked PCB near those transistors myself. Although I've seen plenty of pics from others that have. It makes me wonder if the ones I've serviced are newer and didn't have this issue with the heat on those transistors or if the ones I've come across were powered on in use in better ventilation during their lives?

Maybe some are left on for too long is my guess.

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I have the same burn marks on mine. They are both 2N3906, a very common PNP transistor. They amplify a clock signal to a fairly high voltage. Although my board worked fine, I replaced them when I did a capacitor job because my assumption is that if they were getting that hot, they may have been failing and leaking too much current.

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Affixing little heatsinks to those (especially the original) transistors might not be a bad idea. I've done so in audio applications where they work extremely well.

 

 

DAC59090-4220-4116-AF25-06145FF160D8.jpeg

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