Color Classic analog board active devices, heat sink?

[Lord Refa]

Been rebuilding a fairly nasty board, no real damage but rust, dirt, and corrosion. I removed the square box shield that is near the back end with all the pots to clean it up and there are two packages, one a typical TO-220, and the second a larger package, both had heat sink compound on them. Problem is, I don't remember if they had mica insulators between the shield and the back part of the devices. Does anyone know if those devices had or need to have mica insulators? Thanks!

 

[pizzigri]

From memory, no. But check the heat sink compound, if there was indeed a mica insulator you would see it; and the eventual screw to secure the package to the metal shield would be insulated too, normally with a plastic spacer.

 

[Lord Refa]

From memory, no. But check the heat sink compound, if there was indeed a mica insulator you would see it; and the eventual screw to secure the package to the metal shield would be insulated too, normally with a plastic spacer.

Thanks, but unfortunately I had taken the analog board off a while back and don't remember if there was an insulator present. I did find an small insulator pad which I believe goes to the TO-220, but nothing comparable for the larger package. Also, both use a clip to attach to the metal shield, rather than the usual screw and plastic pass-thru insulator.

 

[Lord Refa]

OK, just checked and the larger packer has no elements connected to the back tab, so it can go in with no insulation, just the big black heat sink connected with compound, the smaller one has its ground pin connected to the tab, so it too does not need a mica insulator.