Lou, Mike, Jim, Adrian and all,
I removed the tubes one at a time.? I let the amp idle (no drive) for 10 minutes with each tube in place individually.?? No signs of anything overheating.? I then replaced both tubes and let it set another 10 minutes, still no sign of overheating.?? I then applied about 20 watts of drive in RTTY mode and was getting around 200 watts out.? (I'm still using my Heathkit watt meter circa 1978)? Attached is a photo of my grid and plate current with that 20 watt drive.? The meter shows 2900 volts when idling and drops to about 2600 when transmitting.?? (I'm operating 240 volts on about a 20 foot length of 12 AWG from the panel.)?
The pictures below are 1.? the front tube at 10 minutes.? 2. the rear tube at 10 minutes? 3. Both tubes back in place after 10 minutes.? 4.? A picture from yesterday of both tubes just after switching off the power (light) which looks to me like both tubes are overheated. 5.? A picture of my meters with 20 watts RTTY drive applied.? The Plate volt meter does return to 0 when switched off.
So it now looks like I may have some kind of an intermittent ??
Thanks again
/John?
W7SWB
