Rocktron

[Valvehead]

need a scem for Rocktron Voodu Valve ..........anyone have one ?

[Jazz P Bass]

"Tube driven programmable 24-bit dsp guitar preamp."

And you are going to fix what?

[vintagekiki]

https://www.gearslutz.com/board/so-many-guitars-so-little-time/947557-please-recommend-tube-swap-rocktron-voodu-valve.html

https://www.gearslutz.com/board/showpost.php?p=10335355&postcount=14

[Valvehead]

"Tube driven programmable 24-bit dsp guitar preamp."

And you are going to fix what?

wont power up.

fuse is good....wall wart is good

[Valvehead]

https://www.gearslutz.com/board/so-many-guitars-so-little-time/947557-please-recommend-tube-swap-rocktron-voodu-valve.html

https://www.gearslutz.com/board/showpost.php?p=10335355&postcount=14


[ATTACH=CONFIG]49842[/ATTACH] [ATTACH=CONFIG]49843[/ATTACH] [ATTACH=CONFIG]49844[/ATTACH]

Too small to see..tried saving and blowing up image..too blurry.

Is there a program out there to do this? Ive tried ms paint...Gimp...Photopad Editor..

[vintagekiki]

https://www.gearslutz.com/board/so-many-guitars-so-little-time/947557-please-recommend-tube-swap-rocktron-voodu-valve.html

https://www.gearslutz.com/board/showpost.php?p=10335355&postcount=14



Unfortunately, images is as it is (too blurry)

[Enzo]

Wall wart OK, as in it puts out whatever the label on it ways? How about is it the right wall wart? I have many times been brought a unit that wants AC wall wart, and they have a DC wart with it. SO half the supply will be missing inside.

Ah, looking for a photo, I see it uses a multipin wart, so likely not that. Still if a unit is just dead, no sign of life, first thing is power supply. Whatever comes out the wart has to get turned into something useful inside. Are there +/-15v on the ICs? The digital stuff probably runs on +5 or +3.3. Are either of those present?

[Valvehead]

Wall wart OK, as in it puts out whatever the label on it ways? How about is it the right wall wart? I have many times been brought a unit that wants AC wall wart, and they have a DC wart with it. SO half the supply will be missing inside.

Ah, looking for a photo, I see it uses a multipin wart, so likely not that. Still if a unit is just dead, no sign of life, first thing is power supply. Whatever comes out the wart has to get turned into something useful inside. Are there +/-15v on the ICs? The digital stuff probably runs on +5 or +3.3. Are either of those present?

Well...heres what happened..i had a mishap. Long story...

Bought the unit un-tested , without the wall wart. i had a 9vac one here , but it is only 300ma output i think. I wanted to see if it would work , So, I soldered some leads to the pcb right after the 4 pin jack. Clipped the wall wart to it , and the unit powered on , but the display was wacky and the lights were going nuts. So...i thought maybe the low power was causing it. Bought a Rocktron wall wart. Powered on---unit works and lights up proper !! So...i wanted to plug it in and listen to it.

powered off , went to clip the 2 leads . The side cutters touched / shorted something (of course ) and i had a small spark.

blew the fuse. replaced fuse...now i have no power. not even AC right after the jack with it plugged in , switch on . wall wart still puts out 10vac .

Right after the ac jack , there are 2 parts on each leg of the ac. they look like box caps and are labeled 223...but, they look like they have 3 pins instead of 2 ...

so....thats where im at and wanted to see a scem to try and see what is going where. i havent been back to the bench to look at it...and i sent emails to rocktron today for one.

[Valvehead]

ok---they sent me a scem today . I will try and post it

[Valvehead]

So what are FC1 and FC2 ?

[Enzo]

Filters. The power lines run through them, with a cap to ground to bleed off any high freq stuff like RF. Look nearby on other power lines, see the little cross line at an angle labelled as "ferrite bead"? A ferrite bead is a small inductor. And I see two of those in each of those filters. SO each part has two series beads with a cap to ground between them. Rare for those to fail. But easy to find out. Unlikely, but is there a short to ground from the power line? And is it open from end to end? Otherwise it is good.

If one has been shattered or broken off you can replace it with a jumper wire to complete the power circuit.

[Valvehead]

i have 3.7k ohms from pin 2 to chassis ground of the ac in jack...pin3 / 4 is 60 ohms to ground

the wall wart is not shorted..and not plugged into the unit

[Enzo]

They are not likely shorted then. Note that pins 3 and 4 are connected to circuit ground anyway.. If you can remove the fuse, do so, I suspect your 3.7k is just the resistance of the whole circuit. Oh, I guess just turn the power switch off.

Those FC parts are really unlikely to fail.

I see +/-15v regulators as well as +5 and -5 regulators. Do you have those voltages leaving all those?

[Valvehead]

They are not likely shorted then. Note that pins 3 and 4 are connected to circuit ground anyway.. If you can remove the fuse, do so, I suspect your 3.7k is just the resistance of the whole circuit. Oh, I guess just turn the power switch off.

Those FC parts are really unlikely to fail.

I see +/-15v regulators as well as +5 and -5 regulators. Do you have those voltages leaving all those?

checked a few and Im seeing -5v at U22

-5v U20
0v U25
+2v U21

ill check some more but havent seen any + vdc anywhere yet , D5/ D10 / D11 are ok

havent had time to look at it , maybe late tonight

[vintagekiki]

Check the output voltages on pin 3 regulators 7815/ 7915/ 7805/ 7905
If no proper voltages, it is best to replace the appropriate regulator with the new.

If there is still no corresponding voltage, most probably a defective some of the tantalum 10uF or the ceramic is 0.1uF in filtering.
It is unlikely that some of the ic peripherals are defective.