For what it may be worth, I seem to have cured a recurrent problem with
overheated filament pins on my SB-220 (which came unsoldered frequently)
by putting a muffin fan directly over the tubes, sucking air out of the
tube area. The amplifier is used in contestservice at ~1200 watts
output on the lower bands and around 1KW on 15 and 10. I had tried all
the usual fixes - swapping the socket springs, polishing the pins,
adding the Harbach fan - but this appears to have been an essential last
step.
73, Pete N4ZR
Check out the Reverse Beacon Network at
http://reversebeacon.net,
blog at reversebeacon.blogspot.com.
For spots, please go to your favorite
ARC V6 or VE7CC DX cluster node.
On 3/17/2013 2:03 AM, Roger (K8RI) wrote:
I do not know of any way to achieve the required air flow at a reduced
back pressure other than an exhaust fan reducing the exhaust pressure
thus making it a little easier to get more cooling air through.
I believe Emtron and OM both use this approach on some models.
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|