freestompboxes.org

Hi,

Does anyone on the forum have a Pedalgear.net JuiceBox? Mine has not been outputting the correct amount of current (I get 50mA per channel instead of 250/500mA). I opened it up and found that of the four voltage regulators inside (JRC MH046b - which I can't locate info on), only two had screws attaching them to the heatsink, and of these two, one was completely loose. My questions:

1) should there be four screws? should they all be attached to the heatsink?

2) am I correct that at least that one loose regulatos could be the root of the problem. The problem is intermittent, but it is sometimes present at power on, and sometimes only after a certain amount of time. It seems like if it was caused by overheating, I would not see failure at power up...

3) does anyone have specs for this voltage regulator - JRC MH046b (I did Google it of course)?

Thanks,

DT

An update… which hopefully will help others who experience the same symptoms:

My juicebox was not working. It was bottlenecking current at about 60mA.

I tried to contact Pedalgear, but they did not respond.

In desperation, and without a schematic, I tried replacing components shotgun style. I replaced nearly all of the usual suspects in the device (caps, regulators, diodes, rectifiers), and yet it still was bottlenecking the available current.

Pedalgear finally answered my email after two months (they seem to have some issue with their email host, and they seem to be bit more focused on the sound installation part of their business, VisionQuest, than on this pedalgear products, which is fair enough). They did not recognize the symptom and could not help over email, so I had to send the unit in for repair. This was a little annoying since I live overseas and shipping is expensive.

They sent it to their tech (who is actually the original designer of the pedal), at first, he could not find any problem, but I requested via pedalgear (I was not allowed to communicate with the tech) that he keep looking at it.

Finally, the tech found that the "self-resetting fuses" had "worn out". Apparently, if there is too much current draw too many times, they lose their ability to reset and start bottlenecking current. If you have never seen or heard of these, they look very similar to poly capacitors. I had never heard of this part, which is why I didn't even think to consider that they could be the problematic component. I believe that one of my regulators went and caused too much draw - which maybe was the cause of the fuses dying. Of course, if I had seen a schematic, or if pedalgear had told me over email to check them, I would have been aware of this part and could have fixed the problem for a couple dollars.

Anyway, it works now, and I can say that the folks at pedalgear are actually quite nice and helpful, and they only charged me 15 dollars for the repair (plus all the shipping). They were however somewhat strangely secretive about their operations (they don't really advertise where they are or who they are and are more than a bit difficult to contact).

Thats all… hopefully this will help someone someday.