Home › Forums › Help/Technical Questions › Holier Grail – Intermittent Fault: due to overheating?

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  • February 8, 2009 at 6:26 am #77708
    Go to bed Jessica
    Member

    Hi guys,

    I have a Holier Grail, which I am running as part of a larger pedal board. I am using the original power supply unit and use it for this pedal exclusively.

    The reverb sound on the pedal is starting to intermittently cut out, while the power light remains on. The dry signal remains intact, such that at 50% blend, the reverb drops out and all I get is my dry sound, and at 100% wet the sound drops out entirely.

    The pedal itself gets hot around the area where the knobs are located, and it seems to be worse after a long period of operation, particularly if it is in a hot room (band practice in summer, no air conditioning, glamorous right?). After opening it up for a look today, I suspect it’s the chip itself which is getting hot and possibly causing this problem.

    Is this a problem that others have experienced? Is there anything I can do about it? Or is the pedal faulty and in need of repairing?

    I am, a “warranty voiding tinkerer” and somewhat handy with a soldering iron, and as the pedal is out of warranty I would be interested in fixing it myself if it is possible to do so.

    Any help or guidance is hugely appreciated. :)

    February 8, 2009 at 12:42 pm #92906
    julian
    Moderator

    did it get hot before it got intermittent or was it always hot?

    February 8, 2009 at 1:16 pm #92910
    Go to bed Jessica
    Member

    To be honest, I’m not sure. I keep it in my pedal case at all times, so it’s very rare that I actually touch it with my hands unless I’m working on my board.

    I do vaguely recall this happening once before, and it was really hot around that time too (I’m talking ambient temperature here – I’m in Australia and we’re having a particularly hot summer). It never happened again after that, until now so I kinda forgot about it. Seems like the combination of sustained use and playing somewhere where it’s really hot (our rehearsal room has no air con) might be a factor.

    I have played with it all through the cooler months with not a flicker of a problem. It is possibly a coincidence though and perhaps not temp related at all.

    My other theory is that there’s a dry joint in there somewhere. I opened it up this afternoon for a look, and all the solder joints look ok (ie. not the dull appearance that you see with a lot of dry joints).

    One thing I really want to know is: Is it a common thing for these pedals to get hot?

    February 8, 2009 at 1:23 pm #92913
    julian
    Moderator

    I’m not sure, but my guess would be no. It’s not like a whole ton of juice is going through the circuit.

    February 8, 2009 at 1:34 pm #92915
    Go to bed Jessica
    Member

    My thoughts exactly, although I did see at least one other post on HC user reviews about a holy grail overheating – which led me to wonder if the heating up is a commonly observed phenomenon with these pedals.

    If anyone reading this owns a Holier Grail, could you please do me the favour of touching the top of the pedal casing between the Type selector and the Gate Threshold knobs after the pedal has been on for a couple of hours and tell me if it is warm/hot to the touch? Even a Holy Grail might give some indication (not sure if it uses the same DSP chip though).

    The adapter is 500mA, which is a decent amount of current for a small device (and I realise that it’s highly unlikely it would be operating at capacity ever, let alone all the time) and some digital chips do get pretty hot with prolonged use (like the ones in computers which need fans and heat sinks).

    February 8, 2009 at 3:11 pm #92921
    The EH Man
    Moderator

    I would suspect a bad solder joint somewhere, possibly on the Blend pot where it solders to the board.

    February 8, 2009 at 8:48 pm #92937
    Go to bed Jessica
    Member

    Hmmm, I might pull the lid off and touch up all the joints I can easily get to tonight and see if that makes a difference. At your suggestion, I will try the blend pot first.

    Thanks guys, the help is appreciated!

    February 11, 2009 at 3:28 pm #93086
    Go to bed Jessica
    Member

    I think I’ve found the problem. I touched up the solder joints for the blend pot and ran into the same issue again tonight. When the pedal started freaking out again, I unplugged the power supply from it and stuck a multimeter on the power supply – turns out the PSU (the original EHX one) is putting out 28v instead of 18v – which, no doubt explains the pedal heating up.

    The pedal will be pulled from my pedalboard until an appropriate PSU has been purchased. Then, and only then will I be sure that this is the source of the problem, although right now I am inclined to believe that it is the source.

    *crossing my fingers*

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