A question about intv parts

[Polish.Gasoline]

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.

 

[mr_me]

Yes those transistors have been known to fail.

[+-^CrossBow^-]

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?

[ChildOfCv]

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.

[Polish.Gasoline]

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 September 11, 2019 by Polish.Gasoline

[Polish.Gasoline]

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.

[mr_me]

You can find the transistor type here.

https://atariage.com/forums/topic/278865-advice-needed-on-repairing-a-motherboard/

 

Edited September 11, 2019 by mr_me

[rmzalbar]

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.

[+save2600]

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.

 

 

[Speedman]

I've also had that on my board and swapped them out for new ones, but still the new ones get extremely hot, about 145*f when i measured the.

I have other issues that need to be check on my board as after 15 minutes it goes black and already changed caps, power transistors, cpu transistors etc... but i'll leave that for another post!

[Polish.Gasoline]

The guy at console 5 says it's quite a strange problem to have on the console.   I'm ordering a cap kit anyways with the other transistors.  My system is fine other than that.  It just a little burnt on the chip I just wanted to replace it so it wouldn't get worse.  Like someone already said when it gets burnt it gets conductive and that's what I am afraid of.  I don't want to do surgery on a board and Frankenstein the thing if I don't have to.

 

I don't know if the console got left on too long if that had caused it don't know but it works without a problem when I play it.  I hacked a cord on one of the controllers cause it was giving me some input problems when tugged.  It works fine now.  After this I'll leave it alone.

Edited October 25, 2019 by Polish.Gasoline