New Rocket blowing fuses

[showsii]

Hey guys, need your help on this one.

I just finished my 3rd rocket and she is blowing fuses. I started my "start up procedures" with my bulb limiter connected with no tubes checking my heater voltages and other voltages. I was not getting anything except for around 50Vac on the mains.

So I removed the bulb limiter. turned it on. The pilot light came on and lasted about 5 seconds and then went out. (fuse blown)


What is going on here? I will post some pics up soon.


Thanks for the help, I need it bad!


Ian

[showsii]

Ok here are some gut pictures!

[IMG764]http://i1112.photobucket.com/albums/k49 ... i/Amp1.jpg[/img]
[/img]

[IMG764]http://i1112.photobucket.com/albums/k49 ... i/amp2.jpg[/img]

[IMG764]http://i1112.photobucket.com/albums/k49 ... i/amp3.jpg[/img]

[IMG764]http://i1112.photobucket.com/albums/k49 ... wnload.jpg[/img]



Does it matter which way you wire the fuse from the mains switch to the IEC ect? Could this be a poor ground off the PT CT?

Any help is greatly appreciated like always!


Ian

[Tillydog]

...I was not getting anything except for around 50Vac on the mains.

...So I removed the bulb limiter. ... (fuse blown)

(Excuse me: )

OK!

What is going on here?

There's a short or other fault in your build that the light bulb limiter was saving your amp from. Take away the limiter and you have the full output of the power grid to feed the fault - with luck the fuse will have blown before any major damage, but this isn't guaranteed.

Are you working through the Paul Ruby start-up guide?

http://www.paulrubyamps.com/info.html#FirstPowerUp

If so, how far did you get, and what are your results so far?

If not, it's highly recommended (IMHO), and going back to the start of the guide (disconnecting the PT and making continuity checks) is the next logical step to figuring out what's wrong (unless you can spot a dead obvious fault with a visual check).

What not to do is to fit another fuse and blindly 'try it again' (you will need another fuse, though )

If you get as far as powering the PT up again, I heartily recommend putting the limiter back in the circuit.

Let us know what you get.

Andy

[badtweed]

I can see from your photos that you have overheated the wire's insulation causing some of it to separate and possibly create an opportunity for shorting. Not enough detail in those photos to verify for sure though.

Verify that your output transformer's primaries and secondaries are not getting cut as they pass through those ungrommeted chassis through holes.

Can't tell from the photos but ensure that you have the secondaries' center taps hooked to ground properly.

A good place to start troubleshooting would be to isolate your power supply from the rest of the circuit and verify that you do not have any unintentional shorts to ground.

For starters, remove the heater lines from that terminal strip next to the output tubes and insulate those two wires with some shrink sleeving for the time being. Now verify that your heater lines to the chain of tubes sockets is not shorting to ground. If you do find a short, then locate the source of the short and correct it.

Even f you have found a short to ground you should still definitely continue with the rest of this procedure.

Remove the HT and 5VAC lines connected to the power rectifier tube socket and insulate them for the time being

Do a visual on your solder joints on the line ac into the amp, the power switch, the fuse holder, etc. Make sure that your wires' sleeving hasn't been melted off by excessive soldering iron heat that would expose the wire in a manner that would allow it to short out to the chassis via adjacent mounting hardware etc.

Once you have that checkout completed, proceed by powering on the chassis so that your power tranny is fed a primary voltage and see if you are still blowing fuses. Do this with the secondaries protected from shorting out with shrink sleeving or some other suitable method.

If no fuse gets blown then power off and remove the shrink sleeving from the secondaries and verify that each is providing the appropriate vac voltage.

You should report back with your findings for what to do next. Hope this helps.

[Structo]

When you had the bulb limiter hooked up what wattage was the light bulb?

A 60w?

When you flipped the power switch on the amp, did the bulb light brightly for a second or two then go down to a low glow?

If the bulb stays bright, you have a short or other wiring fault that is drawing too much current.

Did you let any smoke out?

[surfsup]

I dont think anyone said but yes, the fust should be off the Live side. On your IEC jack, there should be a very poorly molded L and N to designate which side is Live and which is Neutral. That won't cause this though

[paulster]

And, seriously, buy some other colour wires.

Not a problem when the amp is working but you've now made it massively difficult to visually troubleshoot when it should be easy to follow each wire and see that it's correctly headed to its intended destination.

[sunnydaze]

As Paulster pointed out the wire colors make it more difficult to follow the circuit - especially the PT wires. Can't tell from the photo, but if the rectifier heaters are connected to a centertapped heater supply, will blow the fuse every time if the heater CT connected to ground.

Good luck.

[Colossal]

Yes, the tube rectifier leads are green-yellow/green-yellow. Usually, they are yellow/yellow.

I would unhook your PT leads so that the transformer is floating. Energize it, and then test each lead with your multimeter set to AC to ensure you have the correct leads going to the right place! My suspicion is you might have the them incorrectly hooked up (specifically that tube rectifier!).

[cbass]

Heyboer PT? If so looks like the PT is connected correct.

[guitarsnguns04]

I think he's using the hts 5199 transformer ... So the 5 v heaters are not center tapped and the green / yellows are 260v and yellows are 300 . I'm not sure if they are connected to the correct terminals on the tube socket... I can see the guide pin slot. This is just a guess though. Did you have a rectifier tube installed when you fired it up?

[guitarsnguns04]

I just zoomed in a bit looks like your wired your caps to pin 2 instead of pin 8

[cbass]

Looks like you have the First Filter cap connected to Pin 2 of your rectifier.
Shouldn't it be pin 8?

[dorrisant]

When you are ready for another attempt, write down all of the voltages with the bulb limiter as they appear on the voltage chart. Maybe someone here with a working rocket build could verify with the same wattage bulb. If it would be way off, you probably have more work to do before you should try to go with straight line voltage.

If your other amps have similar power supply sections you have the working voltages at your disposal for immediate working numbers to compare to... if so, post what you find to help us all out... don't know if I've seen the voltages with a limiter... other than my notes.

And seriously... the monochrome scheme is only cool to those who would never work on it in the first place.

I'm not trying to be too harsh with the last statement... you have already got a couple of these that work, and that is worth some credit.

[cbass]

I just zoomed in a bit looks like your wired your caps to pin 2 instead of pin 8

You beat me to it by a minute