Built a Weber 50W Plexi Kit

[messenger]

I finished the build and am now just trouble shoooting. I must have a short somewhere. I've been going over this thing for days now and cant find anything wrong

 

[messenger]

 

[wolfeman28]

Just from looking at the pictures we won't really be able to tell what's wrong.

One thing I can say is, you need to work on your wiring/lead dress. Make everything tidier and it'll be easy to work on and less problematic.

Make sure nothing is touching those screws on the board. Is that how Weber says to mount the boards?

Also, get voltages from every tube pin and post them here. Do you have a signal generator and scope?

 

[wolfeman28]

Also, where is the center pin on the bias pot connected? from the pic, it looks likes it's open. It should be connected to the pin to the left of it. If it's not connected, the pot is just a fixed resistor there in the bias circuit.

 

[messenger]

The bias pot middle leg wasn't soldered at the time of the pics but I noticed it while trouble shooting and have since fixed that. The screws aren't actually touching anything, and they are screwed to plastic stand offs. I've actually removed the screws and raised the board a bit during trouble shooting and it didn't change any thing.

 

[FourT6and2]

That's a cluster fuck. Hard to see what's going on due to the wiring. Need to make things neat.

Here's what your lead dress should look like (different layout, but you get the idea).

 

[Tonelover]

Check the thingamajiggy.

 

[threadkiller]

This is why I buy amps instead of kits. Holy fuckin' headache batman. I appreciate that you might want the challenge of the project. Not for me. I can't even wire my speaker cabs up without a cold solder joint. FourT6and2, that thing is a work of art. I don't have the time, patience or skills. Good luck, hope you get it sorted out.

 

[Anonymous]

Wowzer... you gotcha one hell of a mess-o-wires there my friend. It was probably difficult for you building the Weber kit since he doesn't provided detailed build pictures. As everyone is saying, you need to clean up your lead dress (how the wires are laid in the amp) or no one can tell anything. Even if the amp worked, it is likely not gonna sound too great with that lead dress.

My recommendation is that you find some pictures (or ask Weber) of that amp built and re-do the lead dress to match before trying to diagnose the issue (unless you can clearly see one of the component wires touching the screws on that board as others mentioned). It should look a lot closer to FourT6and2's (absolutely meticulous!!!) work than it does now, although it will be somewhat different because of the component layout being different.

Good luck and hang in there! If I got this complete custom to work, you can get yours to work:

Steve

 

[blackba]

Lead dress is an art. Hang in there, you can get it working and cleaned up.

 

[jerrydyer]

give me more symptoms please Ill try to help
whats with the 100 uf bias filter cap??? weeird
I built their vibrochamp it was killer.

I like weber stuff

you guys ever tried the Blue Dog speaker?

 

[srinivassa]

Man, that looks complicated to be a Plexi. The diagram looks so simple. It's pretty well laid out though. I'd say you've got a really good chance at finding the problem. If you don't have a function generator, one thing you can do with a multimeter is a "what is connected to what" test. You just set the multimeter to the 100k range, and you put the testers on pairs of electrical nodes. Infinity means they are not connected. 0 means they are connected. It's tedious, but hopefully some clever guess work can narrow it down. But the tedious parts is that you are just making sure everything checks out with you schematic. Much easier if you understand the schematic and the symptoms enough to isolate where a failure might be. It does work though. I am going to be doing this soon with the attenuator I am building.

 

[Kapo_Polenton]

Dude, I built that same amp kit years ago.... was a BITCH to troubleshoot and i also had issues... i eventually got rid of their cap board (which is too snug in there), got a metro board and did a proper PTP. The chassis is too small for that design.. I also mounted 50/50 caps on side of chassis instead of that stupid layout board Ted designed in there. Was far easier to troubleshoot using a Marshall layout rather than the Weber variation on it. When eventually i got it up and running, it sounded pretty good. Since then i have messed with the circuit but the damn thing just doesn't work. I think it is the transformer. Eventually i just said screw it and i bought real amps. My Lynch Box and 82 JCM800 do what i want them to do, Weber can keep his kit!

 

[jerrydyer]

wanna sell it .

 

[dstroud]

If you can't find a pic go to Ceriatone's website and look at the layout pics of the 1987. That's what I used when I was putting mine together and it was a major help! good luck!

 

[messenger]

Turns out I had the Impedance Switch wired wrong. Not to addresss the Lead Dress issues as it noisy on the Bright Channel. Normal Channel is pretty quiet. There are about 7 extra wires coming out of the OT and PT that I need to snip, and that'll make things look a fair bit neater.

 

[BSRIAudio]

Also, where is the center pin on the bias pot connected? from the pic, it looks likes it's open. It should be connected to the pin to the left of it. If it's not connected, the pot is just a fixed resistor there in the bias circuit.

Yep. You want to run one of those connections across to the wiper so you actually have adjustable bias.

 

[messenger]

Also, where is the center pin on the bias pot connected? from the pic, it looks likes it's open. It should be connected to the pin to the left of it. If it's not connected, the pot is just a fixed resistor there in the bias circuit.

Yep. You want to run one of those connections across to the wiper so you actually have adjustable bias.

I did that. I noticed that when I was looking at the pictures before I put them into my photo bucket.

 

[stratotone]

One thing I always do on my builds is color code the wiring - I use a certain color for signal, power, cathode/ground, etc. Makes it easier to see what's going on.

Also - when you build an amp, take your tiime! It doesn't take a lot longer to make something fairly neat on the inside - you don't have to Roccaforte the power supply wiring with zip ties every 1/4", but a clean layout sure does help when there are issues. Consider using some shielded wiring for long runs too. Don't run signal wires parallel to high voltage too.