Watched the washington warm up on a C5

[brandon7861]

30 seconds of key down/talking, wanted to see what gets the hottest. The AM regulator wins. I think I need a regulator with more surface area or maybe better thermal paste. Same with the transistor in the power supply. I should have put some soot or black tape on the heat sync so that would have shown getting warm too. The low emissivity and high reflectivity of the aluminum makes the bridge rectifier heat sync and the main heat sync look cold. This thing don't record either, so I need to hold my camera up to it and record the screen to get that. I wish I would have thought of that when I got this thing. Looks like the predriver and the final choke warm up a little more than the final does.

 

[sp5it]

30 seconds of key down/talking, wanted to see what gets the hottest. The AM regulator wins. I think I need a regulator with more surface area or maybe better thermal paste.

It needs NPC-RC.
Mike

 

[unit_399]

I think I need a regulator with more surface area or maybe better thermal paste. Same with the transistor in the power supply.

The additional surface area and more thermal paste won't provide much, if any, improvement. You're looking at the temp with the housing off, which allows the heat to escape. With it on, everytime you key up the ambient temp inside the rig increases because air movement is non-existent. So, device temp increases too.
Adding a small fan is your best bet. On my Cobra 139 XLR, I used my heat gun to fashion a piece of ductwork from thin sheet plastic that directs the airflow from the fan right across the driver, final, regulator, and power supply pass transistor. Never did a before/after temp check, but I know it's working because I can feel the warm air blowing out of the cooling slots on the rear panel

- J.J. 399

 

[guitar_199]

I wonder if that would be sensitive enough to temp difference to compare a "mica" transistor insulator and one of these "silpat" insulators that just "stick on"? I've heard of those and even seen sheets for sale.... but my age makes me a little bit wary.....

 

[unit_399]

I wonder if that would be sensitive enough to temp difference to compare a "mica" transistor insulator and one of these "silpat" insulators that just "stick on"? I've heard of those and even seen sheets for sale.... but my age makes me a little bit wary.....

I have been using Berquist SIL-PADS for several years with no problems. Actually, I've been using the Berquist Type 800 insulating material with double-sided adhesive a lot too.

- J.J. 399

 

[guitar_199]

I have been using Berquist SIL-PADS for several years with no problems. Actually, I've been using the Berquist Type 800 insulating material with double-sided adhesive a lot too.

- J.J. 399

and, seriously... you don't need to screw the transistor to the heat sink.... the adhesive on the pads is enough? May have to look in to that......

Thanks!!!

 

[brandon7861]

When shopping for thermal paste, i saw many expensive little syringes and a big tube for just a couple bucks. I went with the big tube. I'm sure just about anything would be better than the stuff i have.

Definitely going to look into those SIL-PADS, I've never heard of them. Thanks!