New ROCKET, from a newbie :)

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DocJames
Posts: 64
Joined: Tue Mar 04, 2008 8:42 pm

Re: New ROCKET, from a newbie :)

Post by DocJames »

Hi all, I'm happy to say that I've got this thing up and running again. I brought home a tiny mirror from the office and had a look underneath. Low and behold the wire had disconnected to B+4. Boy was that fun to put back in, with everything else connected already. I had my wife holding the mirror and got the thing teased back into place, and re-soldered.

I learned a valuable lesson about not soldering on the circuit board while its connected in place. Fischerman, I'll look at that resistor value when I get home to confirm. The B+3, 4, and 5, are stilling running a bit high in comparison to the agreed upon values, so maybe thats causing some of that. Also, I noticed the PT DC voltages coming into the GZ34 were running a bit hot, around 350 on 2 and 8, as opposed to the 294 expected. Is that a concern?

James
Cliff Schecht
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Joined: Wed Dec 30, 2009 7:32 am
Location: Austin
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Re: New ROCKET, from a newbie :)

Post by Cliff Schecht »

That's a bit high yes. Are you running a transformer made for 117V on a modern wall voltage closer to 125? This is enough difference to give you at least 20V over. The other thought is that you are using a modern 5AR4 rectifier which doesn't give you as much voltage drop as a NOS one.. What transformer are you using?

Also from what I can tell all of the plate resistors are 100k, I don't see the 10k mentioned above.
Cliff Schecht - Circuit P.I.
Fischerman
Posts: 819
Joined: Thu Dec 07, 2006 3:47 pm
Location: Georgia

Re: New ROCKET, from a newbie :)

Post by Fischerman »

DocJames wrote:Hi all, I'm happy to say that I've got this thing up and running again. I brought home a tiny mirror from the office and had a look underneath. Low and behold the wire had disconnected to B+4. Boy was that fun to put back in, with everything else connected already. I had my wife holding the mirror and got the thing teased back into place, and re-soldered.

I learned a valuable lesson about not soldering on the circuit board while its connected in place. Fischerman, I'll look at that resistor value when I get home to confirm. The B+3, 4, and 5, are stilling running a bit high in comparison to the agreed upon values, so maybe thats causing some of that. Also, I noticed the PT DC voltages coming into the GZ34 were running a bit hot, around 350 on 2 and 8, as opposed to the 294 expected. Is that a concern?

James
That makes sense looking at the voltage chart. Couldn't understand why you had those voltages if B+ was connected everywhere. When doing those underboard wires, make sure to curl some wire up and around the eyelet/turret so it's sort of 'locked' in place and can't fall out.

I think my eyes were playing tricks on me, that resistor looked brown/black/orange earlier but looks brown/black/yellow now. Sorry for any confusion.
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