Visual Sound Jeckyll & Hyde Problem - RG?

[Paul Marossy]

I modded a Jeckyll & Hyde a while ago for someone. They were very happy with the mods, but a sudden problem developed when the OD side was switched on - it would crackle for a while when the unit is first turned on. It would go away after it was powered up for a little while. He also says that this problem is worse when the pedal has been sitting for a while.

Any ideas what could be causing this? I'm not sure, so that is why I am asking here...

[Scruffie]

I'm no expert like R.G but wouldn't powering up and issues with non use indicate a capacitor problem?

[Paul Marossy]

I'm no expert like R.G but wouldn't powering up and issues with non use indicate a capacitor problem?

I thought of that, but I am not sure if that is the exact source of the problem. I am wondering if it has something to do with the electronic bypass switching scheme...

[jacobyjd]

I'm no expert like R.G but wouldn't powering up and issues with non use indicate a capacitor problem?

I thought of that, but I am not sure if that is the exact source of the problem. I am wondering if it has something to do with the electronic bypass switching scheme...

...or run the LFOs in series :-P

[Paul Marossy]

Run the LFOs in series? Whaddaya mean by that?

[R.G.]

I do keep a log of failures that we see, trying to divine patterns. That's how we found that 9Vac=death for normal polarity protection schemes.

This doesn't match any of the patterns, unfortunately. If it's a V1 J&H (the ones we now call "flattops"), it could be a bum footswitch, as that was common. We ultimately ditched hard mechanical switching entirely based on those issues. However, we've had vanishing little problems with the actual electronic switching itself.

Problems which change in a few seconds to a few minutes are nearly always capacitor or thermal problems. The issue with the problem going away after a while makes me suspect a bum electro cap. If I were repairing it, I would do the following:
1) if it's over five years old, or if it was more trouble that the caps were worth, I'd replace all the electro caps.
2) while I was doing that, I'd remelt all the solder joints.

I'll be very interested to see what the issue is. It's too bad it's been modded - the repair services at the home office are all of good, fast, and cheap.

[Paul Marossy]

Thanks for the tips on that RG. I forgot to mention that it's the most current version of the pedal with the new and improved switching on it.

I guess I could have the owner of the pedal send it to me and I could take a shotgun approach and replace all of the electros in it and see if that takes care of the problem.

[R.G.]

In the most current version, the footswitching is even further removed from switch failure problems. I'd say that unless it's a chip failure - which would be very rare, but not unthinkable - the switching circuit is out as an issue.  A wiring issue would not self-heal in minutes. We did have some issues with the changeover to no-lead solder in some batches of pedals - thank you RoHS, we get to repair/refit/replace and generally eat the expenses - but we solved that with close work with the factory in setup and adjustment of the soldering equipment. So it's possible that it's a solder issue. Generally though, the solder issues were simple failure to work, not self-healing.

I'm kinda back to electros as a first guess. Even then, those pedals are all not very old, so electro wear-out is not such an issue, although infant mortality is always with you. What you want is for the problem to be on the main board where the entire works snaps out on the connector so it's easy to get to and repair. I compartmentalized the misery on that design. Most of everything is super easy to get to and fix. Most of it... 

It's likely a random thing. There's nothing like a random intermittent to make you pull your hair out.

Maybe the best thing to do is to send it in to the office to get it fixed, then re-mod it, if it simply HAS to be modded. With the very wide range of the controls on the J&H, most players don't feel the need to mod them on grounds of actual performance. We do get a small but steady stream of repairs from BUMS sufferers.

[jacobyjd]

Dangit...all this talk makes me really want one! 

[Paul Marossy]

In the most current version, the footswitching is even further removed from switch failure problems. I'd say that unless it's a chip failure - which would be very rare, but not unthinkable - the switching circuit is out as an issue.  A wiring issue would not self-heal in minutes. We did have some issues with the changeover to no-lead solder in some batches of pedals - thank you RoHS, we get to repair/refit/replace and generally eat the expenses - but we solved that with close work with the factory in setup and adjustment of the soldering equipment. So it's possible that it's a solder issue. Generally though, the solder issues were simple failure to work, not self-healing.

I'm kinda back to electros as a first guess. Even then, those pedals are all not very old, so electro wear-out is not such an issue, although infant mortality is always with you. What you want is for the problem to be on the main board where the entire works snaps out on the connector so it's easy to get to and repair. I compartmentalized the misery on that design. Most of everything is super easy to get to and fix. Most of it...  

It's likely a random thing. There's nothing like a random intermittent to make you pull your hair out.

Maybe the best thing to do is to send it in to the office to get it fixed, then re-mod it, if it simply HAS to be modded. With the very wide range of the controls on the J&H, most players don't feel the need to mod them on grounds of actual performance. We do get a small but steady stream of repairs from BUMS sufferers.

Yeah, I was thinking the IC chip was unlikely, but not impossible. And the wiring also seems unlikely, unless something went wonky with one of the connectors on those ribbon cables. I'll look at the schematic on the Overdrive side and see what electros might be suspect.

On the mods, it was mostly just changing some cap values and a couple of resistors in the signal path and tone control section on the OD and dist sides. I don't think the problem has anything to do with the mod itself.

Dangit...all this talk makes me really want one!  

It's a very cool pedal actually. Wide range of sounds available from it.

[R.G.]

Yeah, I was thinking the IC chip was unlikely, but not impossible.

It's not impossible at all. I think that a bad switch chip would be more permanent, not self heal.

And the wiring also seems unlikely, unless something went wonky with one of the connectors on those ribbon cables.

We did have a quality problem once with the ribbon cables; had to send a whole shipment back. That got some attention and they got much better then. But it is possible. I would think that a cabling problem would be more mechanical in nature, like crackling when bumped. The self healing thing is problematical there, too. but it could be.

I'll look at the schematic on the Overdrive side and see what electros might be suspect.

One's as likely as another.

On the mods, it was mostly just changing some cap values and a couple of resistors in the signal path and tone control section on the OD and dist sides. I don't think the problem has anything to do with the mod itself.

Probably not. I have this recurring nightmare with mods on our stuff, not because mods are bad by themselves, but because I spent a long time on what I call quality the hard way - solid mounting, good spacing, checking thermal loads on parts, watching current carrying on parts, built-in attention to ground return paths, which in some cases means an on-PCB variant of star grounding, stuff like that. This is the kind of stuff that does not play well in advertising, because it's about as exciting as balancing a non-overdrawn checkbook. But start constructing higher gain additions and ground a few additions to the wrong ground point, and you have the possibility of some ugly results. Not always, or even most times, but the possibility. And then the problem becomes viewed by the music public as a weakness in the base design.
Sorry - I'm running on. Changing R and C values probably won't get you into trouble, at least in moderation.

[Paul Marossy]

Thanks RG. If I work on it again, I will report back on what exactly the problem is. That is if I find it.