My first build, What should I do before thuning it on?

[Greg]

+1 on that Paulster...It is amazing what you can find with a critical eye!

[Mont]

I don't have a camera otherwise I would have pic's up. I have read Mr worley's entire procedure and gone over the the amp wire by wire, part by part , looked at every pic on TAG and I see nothing I have missed. anyone want to buy some tranny's?

[M Fowler]

Mont,

Your going to just have to go through a voltage check write them all down using the handy voltage chart in the TW file section. We need more information as to what problems you are having. Still won't come on?

Mark

[marcoloco961]

I don't have a camera otherwise I would have pic's up. I have read Mr worley's entire procedure and gone over the the amp wire by wire, part by part , looked at every pic on TAG and I see nothing I have missed. anyone want to buy some tranny's?

It doesn't have to be something you missed. All wires could be right, it sounds like you have a "hot" wire or solder joint too close to a ground or the chassis causing a direct short from positive to negative. At this point I would remove the high voltage wires of the power tranny from the circuit board and test the tranny to make sure you have the proper voltages there. Should be approx. 300 volts DC between each of the yellow wires and ground. Then re-flow all your solder joints. When finished with each one tug on the leads of all wires and components in the joint. you would be surprised how quickly a wire will slide out of a good looking solder joint, when it is actually a "cold" solder joint. Then check each tube socket and it's connections for stray solder "whiskers", flux residue (this can conduct electricity and burn a carbon trail into the board giving the electricity an "escape route" to ground).

The last guy who had a problem similar to yours had one of the positve high voltage leads from the supply caps too close to the chassis, and it was arching to ground on the chassis. Your prob comes after you put tubes in, so I would check all tube sockets well. Turn down the lights and flip the switch once (keep your face back) but look for any tell tale sparking that would indicate a short or carbon trail.

You never did answer my question whether the indicator light lights when the tubes are not in and the amp is powered on. If it does, then I would guess there is a short somewhere in the amplification circuit as opposed to the power supply circuit.

Start testing from the 110 VAC at the power tranny and switch with the bulb limiter, then to the high voltage and heater voltages on the secondary side of the power tranny. If these check out, within the specs listed in the build guide with the bulb limiter installed, then do the primary B+ voltage checks with no tubes in the amp. It sounds like you are good to this point???

Can someone here tell me if it is O.K. to install one tube at a time to narrow down where the problem is stemming from at this point in the trouble shooting??

If this will not hurt anything it might help you narrow down where the issue lies.

[Greg]

Hey Mont...don't get frustrated. When I build...er assembled my Donna Rocket I had a bug somewhere...it would not achieve full volume and sounded horrible. I went through a few grounding alterations but what finally fixed the problem was a complete re-flow of all solder joints. I never found out the exact location but I did fix it.

This actually brings up a good question. This re-flowing with additional solder of all joints actually created many very large solder joints. Is this a bad thing?

[Mont]

The indicator light comes on when there are no tubes. when I plug in the tubes it does not come on. Here is something else. after I turn off the power to drain the amp, there is no charge in the amp....

[Mont]

I am really good at soldering, all my my joints are bright and shiny

[Greg]

So no current to the cap stack? I remember having problems wiring the safety/drain resisters and grounding at my cap stack...try looking there.

I am sure with that specific description you just detailed that one of the TAG pros can offer some actually useful advice. I mostly just annoy people and ask newbie questions.

Just know this...when you do get this dialed in, and you will, it will be so awesome and all this frustration will be worth it!

[Mont]

Here is the problem, with no tubes I get juice to the cap stack. I drain the amp as per instructions. put in tubes. the bulb limiter stays bright and I get nothing to the amp, not even the pilot light. I am going to take out all the wire that is thinner than what is spec'd in the build guide and replace it. nothing against Nik, but I got alot alot of wire that was smaller than 22 awg. to be continued.

[paulster]

Is your pilot light 120V or 6.3V? It sounds like it's a 6.3V pilot light and you're shorting out the heater winding as soon as you put tubes in.

If that's the case then check very carefully the heater wiring at the tube sockets as it sounds like that's where the problem could well be.

[marcoloco961]

Here is the problem, with no tubes I get juice to the cap stack. I drain the amp as per instructions. put in tubes. the bulb limiter stays bright and I get nothing to the amp, not even the pilot light. I am going to take out all the wire that is thinner than what is spec'd in the build guide and replace it. nothing against Nik, but I got alot alot of wire that was smaller than 22 awg. to be continued.

The wire should be 20awg solid. Although too light a guage wire shouldn't cause the symptoms you are describing.

It does sound like the problem is a short near a tube socket. Paulster has hit alot of these troubleshooting problems right on the head. I would check out the tube heater connections and make sure you don't have a 6.3 v heater wire contacting a cathode connection on a tube socket. Maybe just redo the heater connects completely as the problem might be hard to see with the eye.

Maybe check and reflow the ground connect on the center tap of the heaters also. I have inspected connections visually before and found nothing wrong, then reflowed the joint and had the problem go away. It only takes a few minutes. Losing a ground can cause loss of power also.

[Structo]

A big +1 on reflowing the solder joints.

It's usually something you do when you can't really see anything wrong.

Even the pros do it when having trouble zeroing in on the problem.

The solder might be fine looking but when in doubt.

Pictures would help immensely.

Cameras are cheap nowadays, get some nice close ups and these guys can probably straighten you out.

The light bulb staying bright when you have the tubes in mean you have something wired wrong.
Double check all your socket wiring.

You do know which pins are which right?
You count pins from the underside in a clockwise pattern either starting with the gap on 9 pins or at the locating pin on octals.

[geetarpicker]

I agree it sounds like an issue with a tube socket wiring, especially if the test light glows bright as soon as once power is applied even before the tubes are warm enough to conduct.

[M Fowler]

How about the bulb limiter that was built if that is wired wrong that could also be a problem.

[Structo]

Brilliant!

I never thought of that.

Mont, did you wire the limiter so it is in series with the hot wire?