开云体育

When cool this generator powers up with no problems but I notice when I leave it on for about an hour and the internals start to build up heat, symptoms started to occur. The A16 module was flashing on the screen transient failure and when I restarted A19 indicated a test failure. However throughout this the generator was still working. So I let everything cool down for a while and everything runs just fine again, no transient failures or any failed tests, the generator runs like new again when cooled off. Perhaps some capacitors are in question or maybe some IC's or transistors are becoming thermally unstable.

This is similar to the problems I had with a desktop video card, when it would get warm the video would go corrupt and everything would lock up. I attempted the oven trick when I reviewed that others had similar issues and it worked.

Although I am not about to place the boards of the 8642B into an oven, I have a video which you might find interesting that discusses the oven trick I discussed previously.

This video is a link to Youtube, there is some language so be advised.

I tried to duplicate the problem that occurred before. Run the generator at -70dB connected to a receiver with a audio source feeding the FM input with the deviation set to 150 kHz. I probed the test points on the regulator board to see if the +50 +15 -15 +5.2 -5.2 volt were there and steady and they were. After I ran the test for a while I did not run into the issue that occurred before so I checked the regulator voltages and they were fine. I checked for proper voltages and stability which I seen no issues. I will try to repeat this test later and see if the symptoms will occur.

As of the moment this generator works fine, frequency, amplitude, and various functions work as expected. Running the self test in the service mode brings up a failed test on A4 which I replaced that board but it still fails and rarely a19 fails a test yet the usability of the generator seems unaffected.

I realize I made a typo previously on this post. I indicated before A16 which is the attenuator for the 8642A however I have the 8642B, I meant to say A6, I apologize about that. This is the time base module. I recall before when I had the receiver connected to the output of the generator there would be brief occasional? break ups in the signal but it would come back, I finally and briefly got a flashing message stating A6 transient failure but that went away, and A19 was failing a test at that very same time. I turned everything off but did not unplug, after letting it set a while and turning back on everything worked fine.

I should add the problems didn't occur right after powering on the generator, it was a over a period of an hour or more in which the incident finally started to occur. I have used this generator numerous times but not as long in duration and note no issues of any kind other than that moment of extended usage time.