Holy Grail Preemptive Fact-Finding Mission

[cheeb]

I bought a non-operational Holy Grail off eBay. The seller said that it worked fine and then quit turning on. I just picked it up on my way to work and I haven't really had a chance to look at it, but I thought I'd ask for some input on what you guys think may be wrong. My first impressions are:

1. Maybe the LED is bad
2. Perhaps the wrong 9v adaptor was plugged in and it's fried
3. Maybe the old take-it-apart-and put-it-back-together is in order
4. The input jack wiggles loose from time to time and perhaps it wasn't grounding properly

You guys have any other ideas or are any of my ideas stupid from the get-go?

[Mark Hammer]

Cross your fingers and hope its something simple.  Seriously.

Certainly let us know what *does* work.  E.g. passes signal in bypass?  Provides power to the places where power is supposed to show up? etc.

[solarplexus]

if there are protection diodes... check those first.  In the 7-8 pedals I repaired so far for friends,etc, 5 of them were the diodes combined with the IC's (if there was one but yours is digital... it's different).  In some occasions, I spent alot of time trying to figure out what was wrong... the diodes looked fined... but they weren't so even if they LOOK good, check 'em out... you'll save yourself alot of time.

[Processaurus]

My EH Holier grail would bomb every time (no reverb in the mix) if I plugged the wallwart into the wall after plugging it into the pedal, something about the way the wallwart charges up its voltage does something the holy grails don't like when they're trying to boot up.  Dunno if that helps.

[stm]

My EH Holier grail would bomb every time (no reverb in the mix) if I plugged the wallwart into the wall after plugging it into the pedal, something about the way the wallwart charges up its voltage does something the holy grails don't like when they're trying to boot up.

That sounds like a poor reset circuit design for the micrcontroller/DSP 

[cheeb]

BOOM! Fixed. I just attached 9v battery snaps to the 9v in jack and used a battery and it worked like a charm.

Thanks for the help anyway guys!

[Processaurus]

Guess the guy's power supply was dead?

PS It'll suck that battery dry in a second, like the Dracula of 9v batteries. 

[cheeb]

I figured so, but it was the first thing that sprang to mind. It'll work until a get a real man's power supply for it.