This is my good old Cushcraft R7 vertical. I got this second hand some 10 years ago. It has now been unused for a couple of years until this spring I decided to give it a go agein.
Unfortunately it turned out that there was no match on any band. Only one reconance point was found and even that was well above the 7 MHz band.
After spending some time Googling I decided to open the mathing unit to see if there was a problem there.
No obviouus problem was found. It is evident that the provious owner had used way too much power as the balun toroid ( the one on the left ) had run very very hot at some time. The circuit board was brown under the toroid, the cable tie holding the toroid in place was melted and even the plastic box was somewhat bent. All the connectors had some corrosion in them as well.
I took the circuit board out, resoldered all solder joints and cleanded the connectors.
This helped and now there is a nice dip on every band except on 28 MHz.
During testing I managed to contact Japan on 20 meters using JT9 and 20W output so the good old R7 is still going strong.
28MHz still not working but nobody’s there anyway so it is not that bad.