Fender Rhodes MKII WY harmonic Booster not working

[nosaj]

Got a Fender Rhodes MKII WY harmonic Booster not working. Battery is good cannot find any info on it. And its covered in Black Goop
What is the simplest way to remove the gunk so i can fix it? (Not having been through this experience before.)
Thanks,
nosaj

[Jon Snell]

It depends what the black stuff is made of.
Try a small part on an edge with acetone or petrol or ether. That will let you know if it is organic or not.
If epoxy based, there are solvents available, https://uk.rs-online.com/web/p/sealant-removers/7643008 is what I use on Epoxy.

[dmeek]

Try a hot air gun. You might be able to peel it off

[TomCarlos]

That is weird... but if you look at other photos online of this same board, they are covered with the Black Goop. So the board must have been built that way? To add to Jon's suggestion, maybe a little Goof Off in the corner? If it doesn't work on you board, you can find lots of other uses for it.

[dmeek]

From what I can see this is my best guess at the schematic.


The transistor is here. Maybe a 2N3904 or any NPN should work

[nosaj]

Got it stripped back. replaced the 22uf/35 tantulalums with electrolytics( as they didn't survive the goo removal. Popped a 2n3904 in. Gotta hunt for a .0022 polyester cap and then i should be ready to go.
nosaj

They filed the transistor face too.