The click is it the motor relais or the caps ?
And can you post a picture of the goo/plastic ?
Did you check the voltages ?
The jumper seems normal looking at some naked vg8235/20 pics on the internet 
I couldn't tell the difference between the clicks, to be honest.
But, it sounds like the click you'll hear when you start H.E.R.O.
But, that always results in CAPS on AND Motor On, if I'm not mistaken ?
I've removed the small piece of goo/plastic already. It did leave a small stain on the motherboard, so I assume it was at least warm, maybe even hot. Again, when that happened, I don't know. May have been there before.
In the WIKI section, the picture of the jumper next to the diskrom indeed looks the same as the mb of my 8235/20.
I assume the cable in Bas' pictures doesn't make a difference when it comes to the modification(s). That would make it a different vg-8235/xx.
I have not yet checked the voltages. Is there a checklist of some sorts ?
Again, thank you for your suggestions. 
Well, I think the click means the bios is not being started. At least a 8250 does this when you remove the bios. Also it does this when I installed a 7mhz kit and managed to damage one of the address lines when removing the cpu (and I did cut out the cpu and I was really carefull...) Anyway I managed to find it using a logic probe as there was no activity on this address line on the roms.
So probably the only easy thing left to check is if the voltages (5V, 12V and -12V) are correct. These can be measured on the cardridge slot for instance.
Otherwise you will need to use a logic probe or scope to check if all the relevant signals (clock, interrupts, address lines etc etc are working) Just read some of the black screen topics in this forum.
Or you can just check if the wires on the bottom got loose 
The new rom I used, works in a vg-8235/00, so I assumed it wouldn't work in a vg-8235/20, since the /00 is a three rom machine and the /20 a single rom machine. Long story short, I ordered a new rom from Bas to be sure.
Plugged it in...yay, MSX logo, memory amounts, etc. But, no basic screen. I switched the machine off.
That was like earlier experiences, so I feared what was to come next.
Switched it back on. Yes, black screen again. 
I am glad that the MSX gives me some encouragement, but if I'm killing the eproms, it's going to get expensive. Next to that, I haven't found the reason for it not functioning properly.
