Knowing Enough To Be Stumped Fender 5F6-A Bassman Content

[keithb7]

Hi folks, I am working on a building a 5F6-A Fender Bassman, tweed circuit. I am using this layout here:



I have assembled and soldered everything and am now double checking all my work. Also checking continuity with a DMM, verifying my connections are correct.
I know some theory but no expert by any means. Just a home hobbyist. A friend asked me to pull the PCB guts of his Re-Issue '59 Bassman Ltd. I did and rewired it
using a vintage style kit. I reused the transformers, choke and tubes.

I have a few questions. Any help is appreciated.

Is a 2 wire choke polarized? Does it matter what wire goes to which B+ connection? I am thinking it makes no difference.
If you touch the two wires of said choke, you can read resistance. However no continuity. Is this correct?

When I touch the two output wires of the OT, I get resistance measurement in ohms, but I also get continuity.
Is this normal? I am a little confused, scratching my head here. Thinking if I have continuity between the two
OT leads to speaker, I attach the green wire to tip of speaker jack, and black wire to ground of jack, then I measure continuity
from OT green wire directly to chassis ground. Isn't my signal from the OT going directly to chassis ground then?

I turn on on the amp and get no sound at all.

B+ is up where it should be, about 460V DC. More testing to come at other points soon. Thanks. - Keith

[Randall]

A choke is not polarized, which is why both leads are usually black, so it doesn't matter which way you wire it to B+.

Continuity is can be thought of as shorts or very low resistance paths. What are the resistance measurements on the choke and the OT? Chances are the secondary of the OT is only a few ohms or less, which is low enough for your meter to call it continuity. The choke will measure a higher resistance, high enough that your meter doesn't see it as continuity. So if you wire the green wire to the jack tip as it should be, you should still read the same resistance to ground that you did with it on the bench, and that will not be a short. So don't worry about continuity so much, it's resistance that matters here.

[g1]

Yes, it's better to just measure resistance and post those measurements.
Continuity is a bit of a loose term, best used for straight wires, where you just want to know if it is short or open.
Different meters will give a continuity beep for various lower resistances. For example, I've seen some that beep for less than 40 ohms, others that beep with less than 200 ohms.

[keithb7]

Thanks for your response Randall. I was a little confused. I removed the light bulb limiter. The amp fired up and is sounding great.

[keithb7]

For anyone interested, this was a Fender RI '59 Bassman LTD. It was PCB built. A friend asked me to convert it to hand wired. I re-used all trannies, choke and tubes.
B+ caps were moved to inside chassis.

[Jazz P Bass]

Wow!

Nice work.

[g1]

Looks good!
Just one critical note, that mar-ette twist connector over the power transformer. Those are frowned upon for other than house wiring. Perhaps you were just using it as a temporary or test set-up.

[robrob]

Measure and post all your tube pin voltages to help in troubleshooting.