| Author | Message | ||
     Tim Guiher (tim_guiher) Username: tim_guiher Registered: 01-2013 |
Hey MM community. I'm new to the forum and have found it immensely useful in restoring a MM 212 HD130 that I was recently asked to service by a relative. The amp does have the 12ax7 phase inverter and is in great shape other than some minor wear and tear. A quick cleaning of the pots and biasing brought the amp to life which had not been working previously. However, once it warms up it begins to make popping and crackling noises. It does not pop on lower volumes and only occurs when playing in lower octaves (low E and A string). The tubes, which are svetlania el34's, and caps all appear to be original. Is this popping a sign of bad caps or worn out tubes? Or is it a sign that the tubes are overheating? Any help would be appreciated. | ||
| Mike Kaus (mm210) Username: mm210 Registered: 05-2006 |
First guess is either loose/dirty tube sockets or cracked resistor, probably on the bottom of the socket. The vibration and the heat usually cause more trouble as it goes along. I would re-tension the sockets and check the resistors soldered to the bottom of the sockets and while there, just re-solder ALL the connections at the socket. These are the most common things. Let us know. Mike | ||
| Tim Guiher (tim_guiher) Username: tim_guiher Registered: 01-2013 |
Thanks for the reply. I'll check the sockets and re-solder the resistors and let you know how it goes. |