Strange resistance check results at terminal 13- also a speedball question

[12AU7-6SN7]

Hi, I picked up a used crack awhile back.

Everything else in the stock circuit tests good for voltage and resistance. Terminal 13 will start out at 1.3M Ohm then slowly fall to around 280k, then it starts counting up from around 25-29k, I got to 175k before my hands got tired of holding the probes. When I went to resume the test to see if it settled at 270k as it mentions in the manual, it would start over at 1.3M

Is something wrong here? I looked over the entire wiring, the amp sounds good otherwise...

The speedball (I since removed it) voltage checks were all pretty hot except for the 75-90v point, which was around 75. All the other voltage points were above the listed rating, but within 10-15%, on the high end though. The speedball seemed a bit too hot to my ears and I lost some of the room echo and reverb on female vocals for tracks that stand out with the stock circuit. Just trying to make sure everything was working correctly and I just don't like the speedball or if something needs repair.

any help would be greatly appreciated.

[Paul Birkeland]

Terminal 13 can be ignored it if it not close to 0 Ohms.  Terminal 13 can also be ignored if you've bought a used Crack that has been powered up previously.

Seeing 75V on the 75V-90V range indicates a 12AU7 that has emission on the high side.  If you saw 110V DC at either terminal, I would replace the 12AU7.