Fender 5e3p from Wurlitzer organ amp

[Zombie_stomp]

Thanks, Mark! Now I can order parts! I wish I could teleport them, I'm sick as a dog today. Tinkering in that almost-well-again state is the best.

I did find that two red wires from the PT match up with the color and pins in the layout. Two down, a few to go. I'll start highlighting areas that are connected properly on the layout as I go tomorrow and thereafter until it's completed.

[M Fowler]

Mark the power transformer wires before you unsolder or clip the wires.

primary AC wires
filament wires
rectifier wires
secondary HT wires
all center tap wires

[Zombie_stomp]

I only clipped 1 wire off the PT. This was a very complex layout considering the circuit board. One of the wires I cut was a red wire between the output transformer and one of the can caps. The other wire was a black wire from the PT to something I forgot what. The red and black striped wire on the PT goes to a terminal with two black wires that I think went to the auxiliary power outlets, so therefore must have been the hot in. I took a ton of photos before clipping some things apart, so I should be able to retrace the origin of wires. Most of them have something going to the rectifier tube, 3 of which are color accurate and line up directly to the Weber layout.

I will probably have to make sense of 3 or 4 wires that are not the same color as the ones in the Weber layout. The output transformer has most of the same color wires as the Weber layout.

Forgive me, do power transformers ground themselves by their body, or are there hot and neutral wires coming out of them?

Also, I went ahead and ordered all the parts in the BOM just now. Even though I'll be making a simpler amp than in the layout, it will not hurt to have 50 cents extra caps and resistors around.

[M Fowler]

Forgive me, do power transformers ground themselves by their body, or are there hot and neutral wires coming out of them?

No there could be a shield wire usually orange that goes to ground on some PT's. There may or may not be center taps for secondary HT, bias taps and filament. It's hit and miss, no schematic for your old chassis?

[Zombie_stomp]

I was hoping we could put together enough info based on where certain things were connected that I wouldn't need to track down a schematic. I can tell you from pictures I took of the amp that there was a black wire coming from the PT going to a little circuit breaker box which connected with the rectifier, and another that connected to a terminal strip that had the hot wire coming in and distributed that to the auxiliary power outlets.

[Zombie_stomp]

I got a new hotter soldering iron today and had fun desoldering a bunch of unnecessary wires and cut off wire butts. Then I installed the old circuit breaker boxes where they used to go. You can see where the black wire from the PT used to go to the white wires of the circuit boxes. That's neutral. Then the red and black striped wire were tied to the black ( hot ) which spliced together with the power cord and the other end of the outlets associated wih the circuit breaker boxes.

The output transformer wires currently all match the weber diagram except the red wire to the standby switch, which on this amp used to go to a cap can. This amp didn't have a standby, so I wonder if that winding would do the same thing. Then a different color of wire may be shown on the diagram, but besides the ones that do match (power tubes with brown and blue wires to the OT) the green wire, in my amp's case, does go to the speaker out, and the black to ground.

So it's looking pretty good.

[M Fowler]

That red wire of the OT is the CT center tap and if your going to have a standby switch then wire like weber.

[Zombie_stomp]

That red wire of the OT is the CT center tap and if your going to have a standby switch then wire like weber.

thanks, now I am beginning to know what a center tap is. I will wire it as shown in the weber layout, with standby switch. Thanks for letting me know I can!

[Zombie_stomp]

At first I thought because I am only going to have one input that I would need only one 12ax7 tube, but as I was reading some more theory articles, I need them both so I have a phase inverter to make the push/pull work correctly. I'm going to look again, but I'm curious if my stripping it down to one or two inputs instead of 4 necessitates the removal of a set of components from the board, and if so, how much? There is almost another full set of caps and resistors for 2 of the 4 inputs on the preamp.

[Zombie_stomp]

I got myself a Smitty FZ-1a clone in the mail today and it sounds as fabulously swarming buzz as I expected! I'm expecting my batch of Weber amp parts tomorrow according to tracking info. Exciting!

EDIT: my parts have arrived according to a new tracking email! I'm going to go deck it out after I see The Rock*A*Teens show. EXCITING!

[Zombie_stomp]

I got parts! Should I write a separate thread for the build?

[M Fowler]

I got parts! Should I write a separate thread for the build?

No I would continue within this thread.

[Zombie_stomp]

I began situating everything inside the amp, installing block off plates where there was a bunch of stuff that no longer is needed, and a place for two 12ax7s. Now I'm going to have to identify the values of all of my resistors. I have taken a picture of one of them. What I am unsure of how to do is to tell which direction to read the stripes. If I am reading it right, this kne pictured would be 1302x100 ohm one way, or 2203x100ohm read in the opposite direction. It reads "219" on my meter in the 2000k range the most steadily of all the resistance ranges. That's one thing I could use some guidance on.

[martin manning]

The color bands on the resistors convert to 2203, plus the brown band, so 220 plus three zeros or 220k ohms, and the brown band indicates 1% tolerance. There is a slightly larger gap between the brown band and the orange band, which tells you to start at the opposite end.

[Zombie_stomp]

I have some unmarked 9-pin sockets. The PIN numbers are always clockwise from the backside starting with #1 after the gap, right?

What things do I want to keep as far apart as possible? I've drilled a bunch of holes for switches, jacks, and pots, near the power transformer. I just wanted to make sure of any hum-reducing rules of thumb that may exist.