some time ago there was a threat about soldering and desoldering here
https://www.dragonslairfans.com/smfor/index.php?topic=922.0
its the same as the paste between the processor and the heatsink in your pc, so very good available at any pc store if you need it
through the years the paste will be dried out is my experience, and for the cost of new its recomendable to add this paste
Actually, it's much better to get this paste at the electronics store, or even better yet, from dealextreme.com
The "regular" thermal conduct paste is fine for transistors and processors. All those kind of "arctic" paste and stuff are simply hyped up stuff because of the PC overclocking and case-modding scene. The difference in practice often is only a couple of degrees celsius between a 13 Euro paste and a 2 euro paste. Esp. for our goal, this is nuts.
Even worse: some of those Arctic pastes contain metal parts and you don't want to have electrical conductive paste in most cases !
But you are right Etienne, after 25-30 years the stuff will have dried out completely. Replacing it is very advisable. I've done it f.i. on my Amplifone deflection board, and I could FEEL the difference in heat staying at the heat-sink.
Clay Cowgill (from the multi-kits) has recently done some more scientific testing with heat measurement devices, and the results were spectacular to say the least. The (old) transistors will be working much happier after a new layer of paste.
B.t.w. Ckong, wise decision. Are you sure it's not simply a connector problem on the monitor chassis, or a bad soldering ?
My experience in electronics is that the vast majority of problems are simply contact problems.
