Motorola ts907 low hv

[Yamamaya42]

A blue or green glow from a 6BK4/A/B/C is normal, it just means that you are getting a good dose of x-rays, and it would be advisable not to get angry at anything, unless you want to suddenly turn green, increase muscle mass by 300%, rip up everything you are wearing, and terrorizing everyone near you by grunting and growling at them in a primeval nature!

As for not being able to adjust the HV, if it was low to start with, this could explain why adjusting R11 has little or no effect, a test you may try is to REMOVE the cap from the 6BK4 and measure the HV at the point there, this disables HV regulation, so be careful not to let it arc.

If there is no significant rise in HV with the cap off, then the problem is not the regulator, but if it does go up, 22-24k or more, then it is the regulator, if you do see a rise in HV, limit how long you run it with the regulator disabled, as it will stress parts over time.