[Drake] Drake R4C - Unstable VFO

[Robert Wood]

Hello Drake Techies,

I have a possible PTO issue with my R4C.  When listening to CW on any band, the
signal is not stable (tone jumps around) intermittently.  I do not encounter the
issue when switching to my TX4C PTO.  When using the T4XC PTO I can work other
stations with no problems :).

At this juncture, here are the steps I have taken within the R4C:

1. Cleaned all of the vacuum tube sockets and pins (deoxit)
2. Cleaned all of the switch contacts (deoxit)
3. Swapped 6HS6s (Premix Tube with the 1st Mix tube) no change
4. Replaced the two electrolytic capacitors (C163, and C163)in the 150V power
supply section. (I thought I noticed the voltage fluctuating so went ahead and
upgraded the caps)
5.  Tightened the VXO mounting screws.

I am thinking about swapping the PTOs between the units to see what happens, but
before I do I wanted to get other suggestions?  I really appreciate any help.

Thank you very much,

Bob
K5MBA