Problem with Visual Sound 1Spot power supply. R.G.?

Started by rockgardenlove, January 05, 2007, 08:58:19 PM

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R.G.

Quote from: Paul_5 on August 19, 2018, 06:34:51 PM
My trusty 1Spot (of some 5 or 6 years) has developed a problem: at rehearsal tonight (known good, clean AC supply in the rehearsal room) the LEDs on my pedals started pulsing, and there was noise coming from the board. Amp's clean as a whistle without the board, and just tried it at home and it's doing the same thing.

Anyone else had one fail like this?
As an experienced (that is, beaten-upon) power supply designer, I start twitching when someone says that a power supply has failed. Sorry - it'a an occupational hazard. In any system with an identifiable power supply as a separate lump, system failures are always a "power supply failure".  :icon_lol:  Sometimes they  really are.

I have seen many 1Spots fail like this, and most, but not all, have been overloads on the output. Some of them had an internal failure.

The 1Spot "hiccups" as a safety mode. The 1Spot has fairly complete protections inside, with the idea that it's better for the power supply to shut down rather than kill something it's powering. So it internally watches the voltage and current it's putting out, and when it decides that it has a problem on the output cable that it can't safely power, it shuts down for about a second, then tries to come back up. Where there is a load that is demanding too much current for it to safely power, it shuts down, crosses its fingers metaphorically for a second, then tries again. This is the pulsing mode.

So something is making the insides of the 1Spot think it's having to push out too much current. It is possible that this is an internal problem, something like an internal part pulling too much current, or a worn cable on the outside, or a pedal needing a bit more and just pushing it over the edge.

A good diagnostic is to take all but one of the pedals off the 1Spot. Does it still pulse? If so, it's most likely an internal problem unless the one pedal was a digital current hog.

If it works fine with one, add one more pedal; then another and so on.

If you do this kind of debugging and find that the 1Spot won't power a single, pedal, contact the Truetone (formerly Visual Sound) service email or phone. The 1Spot fails so seldom that the boss decided to offer a lifetime warranty at one point. I don't know if yours is covered if it's defective or not. Maybe.

We do have about a 65% no-trouble-found rate on 1Spots returned as defective. But who's counting??  :icon_lol:
R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

Andrekp

My experience:

Like many/most/all of us, I have a breadboard set up where I do my prototyping.  That breadboard setup has a Boss type DC jack.

When I use a One Spot for power on it, just plugging it into the wall, starts a whine/buzz in the circuit on the breadboard - without even plugging in the DC jack to the thing.  The wall wart itself is causing hum to be catchable in the air.  (so to speak).  I have two of them and they both do this.

When I use a Boss wall wart, there is some hum, but nowhere near as much.

When I use a battery, almost none. (just the usual exposed circuit buzz).

These same wall warts, used in a pedal setup, work just fine and don't seem to induce any hum.  Used them for years with no complaints.  I just can't use them on my breadboard.

Now I'm not saying it's not dirty power, or whatever, coming from the wall, or other interference in the air that is being picked up in some way.  I'm only saying what I wrote above.

FWIW.


Paul_5

Thanks for the tip R.G. I'll give them a bell. Tried to plug just one pedal to my Onespot last night and it pulses very faintly; the more pedals I add, the worse the pulsing becomes. Nothing's digital, it's an all analogue board made with discreet components, so I can only assume that there's a fault inside the one spot.

I'll test my board at the weekend using my guitarist's Onespot, and try mine to power his rig and see what happens.

trixdropd

Quote from: Andrekp on August 26, 2018, 01:08:23 PM
My experience:

Like many/most/all of us, I have a breadboard set up where I do my prototyping.  That breadboard setup has a Boss type DC jack.

When I use a One Spot for power on it, just plugging it into the wall, starts a whine/buzz in the circuit on the breadboard - without even plugging in the DC jack to the thing.  The wall wart itself is causing hum to be catchable in the air.  (so to speak).  I have two of them and they both do this.

When I use a Boss wall wart, there is some hum, but nowhere near as much.

When I use a battery, almost none. (just the usual exposed circuit buzz).

These same wall warts, used in a pedal setup, work just fine and don't seem to induce any hum.  Used them for years with no complaints.  I just can't use them on my breadboard.

Now I'm not saying it's not dirty power, or whatever, coming from the wall, or other interference in the air that is being picked up in some way.  I'm only saying what I wrote above.

FWIW.

I breadboard with a one spot and no noise. Strange lol.

Andrekp

Yeah, I think it's strange too.  With a closed pedal, no noise at all, but open, just plugging the wall wart in causes whine.  The Boss does not do this.  I can't explain it.  I have a power conditioner around here somewhere, I may try running it off that and see what happens.