Squeal after recap

[Smoke Monster]

I was finally able to fix the Vectrex today. Of all things, it was a short between one of the voltage regulators and the big heat sink. I added an extra piece of plastic to separate them (thickening the stock piece) and it fired right up.

 

Thank you to everyone for the support and for keeping me optimistic about fixing it

Edited March 12, 2016 by Smoke Monster

[RodLightning]

Congrats. It's always good to read these type of threads, especially when the problem is solved at the end!

[vtk]

congrats, nice to know

 

by the way you say 'plastic', but the actual more correct (official) thing to use there is called a 'mica pad' (i dont know if plastic is good for the long term? and hopefully yours is not too thick, because it might over-reduce heat getting through) ... thermal paste is also a good idea..on both sides of the mica pad (and be careful of the old thermal paste.. i think i read that the original vectrex paste might be toxic after 30 years! perhaps a joke though, i dont know )

Edited March 13, 2016 by vtek

[Smoke Monster]

by the way you say 'plastic', but the actual more correct (official) thing to use there is called a 'mica pad' (i dont know if plastic is good for the long term? and hopefully yours is not too thick, because it might over-reduce heat getting through) ... thermal paste is also a good idea..on both sides of the mica pad (and be careful of the old thermal paste.. i think i read that the original vectrex paste might be toxic after 30 years! perhaps a joke though, i dont know )

Thanks for the info. Now that I know what they're called, I can order a replacement. I'll also coat it in non-conductive thermal grease (AS Ceramique) as per your suggestion.

 

Also, I have a bag of 1N4005 diodes on hand and am up for installing one as an experiment as long as it's safe. Is there any chance that installing it could cause any harm?

[vtk]

Also, I have a bag of 1N4005 diodes on hand and am up for installing one as an experiment as long as it's safe. Is there any chance that installing it could cause any harm?

 

hi again, if you were asking me directly, im afraid i could not give advice here as i only really know the basics (things like testing some voltages, soldering, testing some components like caps and resistors, etc)

 

i did manage to perform the audio debuzz mod (cable), which was good to do (a little stressful but... ok overall )

[Rolo]

Congratulations! If that was the problem, then don't forget the screw. For applications like those, there are insulating distance holders, preventing the screw to short to the heat sink. Or nylon screws.

The 79xx are connecting pin 2 (the metal plate) with input voltage, LM340 and 78xx with common (GND).

 

How about your original problem, the squealing sound?

[Smoke Monster]

Yes, I have it temporarily insulated right now with a thick piece of plastic and I have the parts coming to do it right.

 

The squealing sound completely went away after insulating the voltage regulator, and now I'm working on a different problem that came up. Hopefully it's just a convergence issue.