[Hammarlund] filter caps and power tranny on an HQ-180C

[Bob Camp]

Hi

If the can on a filter capacitor is getting hot then you have a 
problem. When the filter capacitors age they start to leak. The more 
they leak the hotter they get. This puts an added load on the filter 
choke, the rectifier tube, and the power transformer. Eventually 
something gives out.

Best approach is to check out the capacitor for leakage current. One 
easy way to do this is to use an external power supply and a DC meter. 
A $10 Radio Shack meter will do just fine. Lift the wires off of the + 
lead on the capacitor and bias it up to as high as you can get it with 
your supply (unless you have a very high voltage supply ...). The 
current should settle down to under a few ma in less than 30 seconds. 
If it does not then you need to replace the cap.

	Take Care!

		Bob Camp
		KB8TQ


On Apr 22, 2005, at 12:49 PM, ROBERT YOUNG wrote:

> I bought an almost mint HQ-180C last year, it works great, looks 
> great. My
> question is: Is the can supposed to get hot along with the power 
> transformer
> or is it on it's way out, or could it be getting hot because of it's 
> close
> proximity to the tranny and rectifier tube? It gets hot enough to 
> where it
> does not burn the fingers but is a little uncomfortable to touch, the 
> tranny
> also.
> It had absolutely no hum to it even with earphones so I had assumed 
> the can
> was ok but figured I'd ask some more experienced people who have owned 
> these
> Hammarlunds for a long time. I do have some electronics experience. 
> This
> radio has very low miles on it.
> I keep the cover open and run a 12" fan right into the chassis, this 
> keeps
> everything nice and cool but if it is not necessary I'd rather not do 
> it,
> thanks,
>
> Bob Young
> _______________________________________________
> List Administrator: Duane Fischer W8DBF
> ** For Assistance: dfischer at usol.com **
> ----
> http://mailman.qth.net/mailman/listinfo/hammarlund
>