5F1 Start-up Issues

As some of you may have seen in my previous posts, I am in the process of building my first amp. It's a 5F1 based on the Boothill kit with a few minor substitutions from on recommendations here (e.g., different pilot light) and for parts that I happened to have on hand from recent repair projects. I've "completed assembly" and have everything together in the chassis. I'm following this start-up procedure:

• Without any tubes installed turn power switch to on and about 3 then plug in amp - pilot light illuminates and the fuse doesn't blow so that's a positive sign. Let it idle for a few minutes...no smoke, no smells. No shorts to the chassis, etc.
• Still no tubes installed. Measured voltage across pins 4/5 and 9 on V1 filaments at 7.21v. A little high but doesn't seem like anything to worry about at this point.
• Unplug amp, turn switch off, drain caps using snuffer stick, and installed new TAD 5Y3GT. Plug amp in, power on. Rectifier tube glows a pleasant orange. No smells, no smoke. Voltage at pins 4 and 6 measures 349v and voltage at pin 2 measures 5.37v.

Here's where the problem comes in... When I then move to measure the B+ at the positive lead of the first cap (C3) before the voltage dropping resistors (R10) I get essentially nothing. I thought it might be a problem with the lead from pin 8 of the rectifier tube (V3) to that post but I get the same bleh reading on pin 8 directly (B+ DC out).

Thoughts?

 

Not sure specifically what B+ ground means but I used my multimeter to check continuity from the negative leg of each of the B+ filter caps (C3, C4, and C5) to the chassis and they all make it beep happily. Am I checking the right thing the right way? Thanks!

 

Good catch on my typo! It's wired as follows: Yellow 5v runs to 2 and 8. Red HV runs to 4 and 6. I will correct my original post for clarity. The reading off pin 8 and on the lead into C3 is what doesn't make sense...

 

Sorry, typo! It's wired exactly as this diagram is depicted. I've checked against the Boothill diagram and robrob's.

 

Okay, King Fan called it. In my haste to start poking at things and get readings I did NOT set my multimeter correctly. Now showing B+ of 472v at pin 8 on V3 and at C3. Every other measurement checks out in range as I add V1 and then moved on to V2 + speaker. Sounds glorious! Off to play test a little more. Thanks for helping!

 

Yeah, on the color coding, there's two wires I really wish I had color coded...the two that run under the board, exiting through the same hole to V1. Had to do use my multimeter to figure out which was which. <sigh> The others are easy to trace on this simple little guy. Next build!

 

Thanks. I'll look into making one. I was following the start-up procedure in the StewMac kit instructions as it seemed to be the most thorough, step-by-step reference that included where to take all the measurements and what values to expect (more or less).