Is contact with Pioneer 7 or 8 still possible?

Question

Pioneer 6 to 9 are a series of scientific probes launched 1965-1968 that orbit the Sun at about 0.75 to 1.2 AU. Would it still be possible to contact Pioneer 7 or 8?

This question asks a similar question about Pioneer 6. This answer muses about the possibility of contacting 7 or 8. The Wikipedia page for the spacecraft series states that attempts to contact Pioneer 9 in 1987 failed, so presumably there is no point in trying with that spacecraft again. But the last contacts with 6-8 (in the 1980s) were successful.

Not to be confused with Pioneer 10 and 11, which are inactive and on a trajectory out of the solar system.

Answer 1

It's not impossible:

1. The Pioneers have not been switched off (as evidenced by the later successful attempts to contact them).

2. They're in constant sunlight so no thermal cycling which increases their life expectancy, and no batteries are necessary.

3. There has been at least 1 other case where an old spacecraft was found to be alive after years of no contact (ISEE-3)

but we don't know for sure until we try: the spacecraft may have fallen silent due to any number of failure modes since the last time NASA contacted them.