Mex
I sent you a few pics to your email address --- hope they made it all the way down south - Did down size them (1024x768) and happy to send again at full res they are 5meg a piece full res.
No need for a 50vdc cap - the voltage is NOT the issue - doubt that section of the circuit ever sees more than 15Vdc - it's the heat from the large resisters that kills the cap - suggest you use long leads and move the cap away from the heat source and use at least a 105C rated cap. Additionally it's an ESR sensitive circuit get one with low ESR as in <1 Ohm . Again this modification depends on your model #
Regarding pin #7 that is if and only if you have an 9800 series - again without a model number we are shooting in the dark at best - once in a while we might get lucky but not too often. Most of the components on the 9800 series are surface mount you WILL NEED good glasses and lots of light
The 62K is only a rough in - might want to use a 50k pot with 25K in series - many ways to skin the cat - but again that is for the 9800 series ..........
PS - "Open Frame" depending on model #, Most if not all WFCO's are NOT conformal coated PCBs - Dampness, salt air, excessive heat, dust, dirt, bugs, etc........ will destroy it in no time - strongly suggest it be kept in a human compatible environment