[Hammarlund] SP-600 AVC issue

[Adam Vaughn]

Hello everyone. I picked up a SP-600 J-25C a couple of years back, and only recently had it re-capped. By and large it works fine, but I've noticed an issue with the AVC circuitry. From time to time, the incoming signal will overload the set, and the needle on the S-meter will repeatedly attempt to pin itself to the right, sometimes accompanied by the signal going silent and/or 'fluttering' along with the needle's movement. Turning down the RF gain control doesn't help; in fact, some vestiges of the overloaded signal can often still be heard from the speaker even with the control set at 0. Toggling AVC/MVC with the RF Gain set to 10 doesn't help, nor does changing bands or re-tuning. I have to toggle the AVC/MVC switch after turning down the RF gain in order to bring things back to normal, at least for a time. I've tried changing out V14 in favor of a NOS JAN 6AL5, but to no avail. Any ideas where I should look? Thanks in advance!-Adam

Adam Vaughn
Collector of old computers, video game systems, radios and other electronic equipment...Visit my page athttp://www.electronixandmore.com/adam/index.html