[codefox1]

Okay, agree with eveyone. There is another reason for mechanical thumping of transformers. If the transformer was selaed in wax withing the bells, and ever overheated due to operational stess or being stored in a very hot place like an attic in the summertime, some or all of the wax might have melted and dripped away. Often you can find artivacts of this as lumps of wax on the chassis, or if long enough ago, rust spots. So if the windings are slipping on the core, you could easily hear a thump or buzz when the set is turned on. I have seen articles where people have soaked old transformers in varnish and baked them in ovens, and on and on. I have one nice amp which exhibits this same behavour, but otherwise plays just fine. On the other hand, I have seen cases where the filter caps are going bad, not enough to blow the fuse, if in fact the set has one, or to blow the rectifier, be it a tube or solid state, or a bad coupling cap in the output stage, but a pig on power nonetheless. This would be accompanied by the hot tranny syndrome, and confined to the narrow definition of radio diagnostics, being a symptom worth investigating. I have rescued quite a few transformers that had arcing connections, starved and overheated windings, excessive ringing and thumps. God help me, but I have secured loose ones with a liberal glob of Elmer's Glue left to dry for at least a week atop the furnace before returning to the bells. Works.