TSL100 Bias Problems

[bmd]

I was on here before with a bias problem with this amp and you guys helped. At the time I was getting about 45mv V5 & V6 and over 100 on V7 & V8. The amp would make a crackling sound through the speaker. I changed the GT EL34 LS that I had in it back to the SED'S that came with it. I have a cheap Jackson model 48 tester that showed one of the GT's bad and the SED'S were still ok. Now, this amp is acting funny again. About a week ago at rehearsal I noticed V5 was not lit and the amp sounded really grainy. V5 is lit now. I will bias it to 90mv per side, turn it off, come back 20 minutes later, check bias again and it's down to 84 or 85mv (sometimes it creeps up the longer it's off standby), set it to 90mv, turn it off, come back later, check it and it's 95mv. It keeps doing this. Now it will making one crackling sound and V5 & V6 are going down to 45mv.The seds still check out ok.I did put a 1000v 8a bridge rectifier in it and the amp worked ok,then this started.
Has anyone had this problem before? Can anyone give me advise on what to do? What parts to replace/upgrade and how to locate/identify them?
Any help is appreciated.

[WholeToneMusic]

crackling

You may want to check v5 socket with a continuity tester to make sure it's not shorting out, the socket may also be arcing.

[fdesalvo]

Dude, did you resolve this issue? Please have a look at my post about my TSL. V6 is not lighting up and the bias is skewed from one pair to the next, as well.