[Heathkit] RE: SB610?

[ehertz]

Hello all!

Update on the 610 single tone output. Through careful and time consuming tracing, I located one faulty soldering joint. The join allowed B+ to get to the plate of V4B but not V4A! I was very luck and thrilled to have located this fault. I resoldered and things are slightly improved...

Now, while watching the tone output on a scope: When I go from "off" to "1.5 KHz tone" I see a *momentary* sinewave on the scope. It then seems to fade to zero in about 1/2 second or less. Every time I go from off to 1.5 I see that momentary sinewave.  

So it seems the signal may be being dampened out and continuous oscillation is not occurring.  So I kept looking...

I believe I located an incorrect component value.  Seems the resistor from the first grid of V4A (pin 5) is supposed to be 270K. On my unit, it appears to be 220K.  Can anyone confirm that this could in fact be preventing this from oscillating?  If the answer is no, I'd rather keep looking and leave that there. Its really burried under a ton of other components. 

Any insight appreciated. thanks!
Eugene