New rocket build yields smoke...

[KellyBass]

This one's got me scratchin' my noodle. Just fired up my latest rocket build. Was waiting (in standby) for everything to warm up, when I smelled that smell. Quickly turned it off to find that my 100k bleeder resistors (coming off the 2nd filter cap) were scorched. I'm using 47uf filter caps in c14 a&b and c15. Could this be a little much for the valve rectifier? I've used these values before with no problem.

Earlier when I was using my bulb limiter, I was just getting the slightest glow with no tubes in. I've tested the rec tube and it works in another amp. Wiring has all been checked. Thoughts?

[passfan]

Could it have been a hundred ohm resistor instead of a 100k ?

[jaysg]

100K 3W resistors? Make sure one wasn't a 10K or something like that.

[KellyBass]

kind of hard to tell what value they were at this point...they're black and one of them measures 42meg while the other measures 2 ohms! Good suggestion, though...i'll make double sure the next pair are legit.

[JamesHealey]

well if they were 100k they're not anymore lol.

[passfan]

Given that your test lamp indicated low current draw at startup, the only way they could draw any current would be to ground and it would appear the draw was low, i.e. normal. That being the case they would have to burn themselves up one way or the other. Had to have been either wrong size or wrong value or just plain bad. Could be the 42 meg one was high enough to dump all the load onto the one reading 2 ohms now ? I guess you switched it off before it could burn all the way in two.

[KellyBass]

The bleeder resistors probably did read the same value at a "less burnt" time in their lives, but I can't say for sure it was 100k. Next time, I'm going for more robust ones...and confirm their value.

Something still doesn't seem right, though. Why so much current draw? I still can't get past thinking that the 47uf reservoir cap may be too large. It seems like I read on Merlin's site that the first filter cap should not exceed 60uf for a GZ34 and the second cap is not as critical. Maybe the 47uf is pushing the rec. tube a little too hard? Plus, I'm using these SGI caps and I've never used them before.