F5 power amplifier

[alazira]

Originally Posted by cviller

I think a common goo mistake is to apply too much - the thermal paste or goo is not supposed to do more than just fill out the cracks.
Here are some guides to apply paste to cpus - the theory applies equally to mosfets.
Arctic Silver Incorporated - Arctic Silver 5 Instructions

I remember that advice from building computers - use a very thin evenly applied layer. However, in my case, I apparently used too thin a layer as it didn't fill in all areas and left some air pockets. So a little squeeze out is better than not enough

[hags]

Originally Posted by Zen Mod

nope - if you use decent "security" washers ; dunno what's English word for these , but that's small spring steel washer , right under screw head

I think you mean lock washers. I haven't used them. I use fender washers, I find, at least with sil-pads, they distribute the torque much more evenly than without.
I have noticed they never need to be retorqued but IMO it's just good practice to check.

[Zen Mod]

you MUST use fender washer , but - beside fender washer - I'm using lock washer to ensure constant pressure - even if I'm mostly using mica & goo

funny - I found that old ( non valid , but also even valid ) coins are best for purpose .... almost as they are last pieces from personal stash of Baron Krupp ......

[hags]

Originally Posted by Zen Mod

you MUST use fender washer , but - beside fender washer - I'm using lock washer to ensure constant pressure - even if I'm mostly using mica & goo

funny - I found that old ( non valid , but also even valid ) coins are best for purpose .... almost as they are last pieces from personal stash of Baron Krupp ......

Way to throw money at the problem!

[JimT]

Originally Posted by Zen Mod

you MUST use fender washer , but - beside fender washer - I'm using lock washer to ensure constant pressure - even if I'm mostly using mica & goo

funny - I found that old ( non valid , but also even valid ) coins are best for purpose .... almost as they are last pieces from personal stash of Baron Krupp ......

What are those white insulators on the joints to the mosfet?

Jim

[labjr]

Originally Posted by JimT

What are those white insulators on the joints to the mosfet?

Jim

That's Marshmallow Fluff

[alazira]

Originally Posted by labjr

That's Marshmallow Fluff

Or silicone grease. But with Zen Mod you never can tell.

[flg]

Originally Posted by Renron

Ummm.
Looks like Papa uses the same as most of us; washer and lock nuts (aircraft nuts).
Ron

I believe I said Papa also uses...

Originally Posted by labjr

They look like allen head screws.

I beleive the term is Socket Head Cap Screw. The ones pictured look Stainless or plated. "aircraft nuts" is not even found in Wikipedia??? The English term would ussually be screw or possibly bolt. I did not see any nuts of interest? Aicraft or otherwise. Ummm, were you thinking of balls to the wall

Originally Posted by Zen Mod

nope - if you use decent "security" washers ; dunno what's English word for these , but that's small spring steel washer , right under screw head

That looks like a spilt lock washer ZM. There are other wavy looking " springy" washer devices that can work well but, you need to keep equal pressure all around and if not sized properly they won't be.
I guess the real reason for this post, other than feeling piled on when only trying to help, can be found in the Zen Version 8 article, by The One an Only himself: "Q2 is mounted on a heat sink like any other power device, but we pay special attention to the mounting of Q1. I mounted mine directly on an anodized sink, using thermal grease and about a pound of pressure from a clip."

AaHmmm

[labjr]

I think "Aircraft-Grade" as is "Surgical Grade Stainless" and "Used by NASA" are terms used to sell everything from Tempur-pedic mattresses to Ginsu knives.

[flg]

And, traditionally Socket Head Cap Screws were easily available in SAE (Probably only a North American standard) grade 5 stainless or grade 8 carbon black. Very good quality stuff. Today however you can get cheap copies and plated decorative ones of all types.
When I experimented with the LU1014D I used a clamp, with a screw, as in the profile view below. The JFET has no mounting hole,