marantz amp transistors

marantz amplifier PM-84

the output transistors are screwed to a big aluminum heatsink. the transistor terminals are not soldered but simply push into sockets. i was thinking of cleaning the terminals with some steel wool then spraying the sockets with contact cleaner for a better connection. is this a good idea? are there better alternatives?

the original problem was humming(a couple of high esr caps and some dry joints)

If the TO3 socket contacts and/or transistor leads are not oxised or covered with green verdigris then I would simply not bother. The socket contacts are fairly solid and have sharp edges which will quickly clean off anything after plugging and unplugging once or twice. You might spray with some contact cleaner/lubricant to ensure the good electrical contact.

No steel wool... You don't want that stuff around electronic components or circuit board. Usually the contact in those TO-3 sockets are real good.... just unplugging and then re-plugging in the transistor will be all that is needed. For clean up use contact cleaner or in the worst case a pencil eraser to remove oxidation and then contact cleaner. My best advice.... if it's not broken, don't fix it. This would not be the cause of humming.

-- Best Regards, Daniel Sofie Electronics Supply & Repair

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sofie wrote: : No steel wool... You don't want that stuff around electronic components : or circuit board. : Usually the contact in those TO-3 sockets are real good.... just unplugging : and then re-plugging in the transistor will be all that is needed. For : clean up use contact cleaner or in the worst case a pencil eraser to remove : oxidation and then contact cleaner. : My best advice.... if it's not broken, don't fix it. This would not be : the cause of humming.

Agreed.

The TO-3 leads typically are plated or tinned. Using an abrasive on them may reveal a more-readily oxidizable metal in the core of the transistor lead.

b.