Someone recommended Simichrome polish and I used that.Metal polish generally includes a corrosion inhibitor, commonly an aliphatic or synthetic wax.
How did you polish the chassis?
Simichrome contains diethanolamide as an anticorrosion coating, but the MSDS doesn't specify much. I don't know how well it works.
You could try polishing it again and then coating with a synthetic car wax to protect the surface since it seems to be prone to corrosion.
Based on the reviews, I was going to try using one of the car resin glazes (BlueMagic TR-3) to seal the surface on my next chassis project. I do not, however, yet have any direct knowledge of how well it works.
Great work xbart. I took the cover off my modded ST40 to check an OPT number for another thread here, and was reminded of how pitted my chassis is, and also how I had to clean the sockets and replace those carbon comps to get mine quiet. But the chassis is built like a tank, e.g. that bottom plate with its 13 securing screws.
I'll be interested to see how you go with those tone controls and associated PECs. (Mine are marked Sprague 29751.) If you exclude them, you lose part of the goofy charm of the multiple controls, but probably gain sound quality. Another route is also have an input direct from from Tape 1 and Tape 2 inputs to the driver tube grids, for a power only option.
The Simichrome polish is holding up well, with no signs of oxidation.Since it's been a few weeks, I wanted to ask if the new polish with the synthetic wax as a corrosion inhibitor helped to prevent new oxidation or rust?
I'm following your lead and ditching them also, Thanks anyway!I probably have extra controls, since I normally remove them.
I'm going with just 3 inputs (see my revised schematic). Phono, CD & Aux.Just a suggestion. The 70 had a wonky input selector set up (not for it s time frame but for modern use) AM/FM , Tape head. If i were as far down the path as you are now i think i'd try to make more useable inputs.
I'm following BuzzK's build of his Eico ST-70 Rebuild Redux, from his write up, it was nice sounding.I missed this one until now. I know when i finished mine and was exchanging emails with Dave G , he seemed to like the 2080 design than the st70. I'd be lying if i remember exactly why. I think the part setup matches pretty well with the 70 having a few part choice advantages. I'm reaching here on my poor early morning slightly caffinated memory. I think 80 used 12au7 instead of 6sn7 and it used some nearly equivalent 6v tube where the 70 used an 12ax7. I kind of remember the sequence of the volume, tone balance was different. I think that was where the 80 had the advantage. You make want to ask him. I wasn't motivated enough that when he told me that i would go rip it apart and start again. I really like your clean up work,