Line 6 DL4 delay modeler wont power on- help!

[methodofcontrol]

hey guys...i need some tech help w/ my DL4.
i need to know the MA draw, (i know the back of the pedal says 1200ma, but i read somewhere that they only really draw 300ma max typically.) and i need to know how to remove the circuit board. i can't figure it out, i don't want to apply so much pressure that it breaks.
need some help!

[Mark Black]

Howdy -

I just worked on one of those (didn't check the current draw - sorry).

Couple of things about removing the PCB:

I used a piece of bicycle inner tube to pad the jaws of standard slip-joint pliers to pull the knobs. Keep track of which knob goes where - on the one I did the far left knob did not have the plastic spacer under it. Maybe it did once and was lost in some previous repair attempt.

Remove all the jack nuts.

Do NOT loosen or remove the footswitch nuts. They are just actuators with a spring pushing on a tact switch soldered to the PCB and can stay in place.

Mark and desolder the two wires coming from the battery compartment at the PCB.

Remove the screws holding the PCB to the case and you should be able to lift the PCB out by pulling up on the front edge. It should come easily so if it doesn't then double-check for a missed screw.

I used a power supply from an American Audio DJ mixer which was 9VAC @ 1000mA and it worked just fine. Maybe Line-6 put that 1200mA rating on there to make sure you could only find a replacement from them. I ran into something like that when trying to find a replacement for a wall-wart marked "13VAC" for a small laser - turned out it was really only putting out 12VAC so replacements were easy to get.

Other than that - good luck! I've never been able to get any service support from Line-6 whatsoever, not being factory-authorized.

Mark

[methodofcontrol]

hey mark, thanks for the input. i figured i needed to remove the knobs, but they weren't coming up easy, so i put the project on pause until i i could get confirmation. thank you for that.
what was wrong w/ the one that you worked on?
i have an adaptor for a captain coconut that is 9vac, 1000ma...i thought it should work, but i bought this pedal broken....so i haven't actually seen it work w/ my power supply yet, so i wasn't sure if i had enough milliamps.
if you read the line 6 FAQ page, there's a part where they say the pedal will also work fine off of 12vdc, 500ma.
yeah....they're just trying to sell as many power supplies as possible. what a bunch of jerks.
once i take the board out, hopefully i'll find an obivous burnt resistor or lifted trace or something. otherwise i'm at a loss for the moment.
any other suggestions from anyone w/ a similar situation?

[Mark Hammer]

I've had the pleasure of serving as a beta tester for the Tone Core series of pedals, and I have to say that I found L6 to be very thoughtful as regards powering and a number of other things. You may not agree with their choices, but they HAVE thought about them. It may be that the 1200ma recommendation is for those folks who insist on powering multiple pedals with one wallwart daisy chained.

I find that a number of recommendations that accompany commercial pedals with respect to power are intended to simply avoid problems in users who do not fully comprehend powering effects. I'm not trying to insult anyone, but out there are millions of folks who:
a) don't know the difference between AC and DC
b) don't know how to read voltage and current specs on the adaptor itself
c) don't understand the impact to the circuit of reversing the DC supply lines (jack polarity)
d) don't know how or are otherwise unable to measure anything electronic about the wallwart or pedal

The manufacturer has the option of either leaving the consumer to their own devices and letting them blow up their stuff because they are too underinformed to use it safely, giving them a 10-page brochure which explains enough to avoid trouble (if the person would read and comprehend it, and if it were written properly), or simply saying "Here, buy this and ONLY this and your worries are over". Though I suspect it is a strategy a little too overinformed by the legal department, they generally choose strategy C. Love it or hate it, it is done so that what you buy from the company lasts a long time, even to the point where you sell it 2nd hand or even 3rd hand (which the manufacturer, of course, never sees a penny of).

[Mark Black]

All good points Mark H. I really like the manufacturers who make their stuff operable from a variety of sources like anything between 9-18VAC or 12-16VDC. I'm sure you have seen some of those.

I lucked out on the one I did last. It powered up OK but had no effect, and after a bit of poking around I got to thinking one of the two relays was not clicking. I then verified by holding a chopstick on it with the other end in my ear as a kind of cheesy stethescope (from my mechanic days). When I desoldered the relay with the notion of checking it out-of-circuit I noticed something kind of funny: the silkscreen graphic underneath indicated it had been installed backwards. That one got a smile out of me, especially considering it looked like pristine factory solders. Re-installing it correctly made everything all good.

So, considering the pedal looked a little worn but could never have worked right, I had to ask the guy at the guitar shop who sent it to me for repair what the history of this thing was. He says it belongs to a buddy of his who always said this particular DL4 sounded "special". Hope I didn't screw up his mojo...

I guess I would start by making sure the power jack is well soldered and the normalling switch contacts in it are functioning. Then I would check the diodes in the vicinity of that jack. After that the power supply gets a little more complex as they have some scheme to derive several voltages even when powered by the batteries. Maybe Mark H. could shed some more light on that...

Mark

[methodofcontrol]

yeah i'm not getting any voltages on the other side of the pwer jack. soi'm thinking it may just be the jack.....but it looked to me like the the batteries came into the circuit after the power jack....so if the problem is just the jack, then the unit should work on batteries just fine. (which , i was told, it doesn't.)
any of you have a schematic? i know it's supposed to be proprietary, but if i could just get some confirmation on the power section...that'd be great.
or perhaps a sneaky individual could email me the schematic. i won't tell.
methodofcontrol AT graffiti DOT net

[methodofcontrol]

ok so...just now i resoldered the power jack and the pedal started working perfectly!
however, i tried the loop mode and when i started overdubbing, the buttons locked up (electronically) so i couldn't get out of it except by pulling the input cable.
and now it won't pwoer up again.
i'm using a 9vac, 1000ma adaptor, when i measured it from the wall it was putting out 10+vac....is it possible i overloaded the pedal? i wouldn'tthink so...but i'd like a second opinion.

[Mark Black]

I wouldn't think the extra volt on the PSU would be a problem. They usually read high when unloaded anyway.

The fact it worked for a bit after you re-touched the power jack solders makes me wonder if there is still a problem there, with maybe a cracked trace or something. Try scraping a little of the solder mask (green stuff) off the traces near the jack solder points and re-do it again so the solder flows a little further out onto the trace and hopefully over any crack.

After you do the re-touch it might be beneficial to do a "factory reset" on the pedal as well. Unplug the power, hold down the outside footswitches (A & D), and while holding those down plug the power back in. The footswitch LED's should sequence back & forth indicating a successful reset. Of course there has to be a plug in the input jack to make the power work at all...

I usually do the reset a couple of times and then cycle the power once more to get to ground zero.

This would also be a great time to re-touch the solders at all the jacks and pots just preventatively if nothing else. Maybe the switches too.

Mark

[methodofcontrol]

welli removed the power jack from the board and gave it a continuity test w/ and w/out anything plugged in. it passes voltage, points are connected that should be. i put some de-oxitin it to to help w/ conductivity. after reinstalling the power jack, i tested for continuity along the board traces and found them to be good as well. so now i'm not sure if the problem is at the jack anymore. but now it still won't power on.........hmmmm. not sure where to go from here. i can start checking voltages....but i don't know what voltage should be where w/out the schematic. any more suggestions, mark? thanks so much for your help, by the way.

[Mark Hammer]

I don't know if this is the issue, but...

Barrel plugs come in a variety of sizes. The size spec is given by the diameter of the center pin. So, a 2.5mm plug will fit over a 2.1mm pin (with wiggle room), but a 2.1mm plug will NOT fit over a 2.5mm center pin. Certainly the external diameter of the plug varies with center pin size, but there are a variety of plug sizes that are more or less "compatible" with different jacks. Okay, put that thought on the back burner.

Because of their physical design, phone plugs generally use the tip to move a leaf contact out of the way and switch from one default "hot" contact to another. So, the old-style EH mini phone plug adaptor inputs would use the tip of the phone plug to switch from battery to wallwart. Of course, if you attempt to plug a "live" wallwart plug into such a jack, you can easily short the tip and shaft during insertion, generating sparks and other nonsense that consumers prefer not to encounter. So, for those reasons, manufacturers generally use the more awkward (but bulletproof) barrel plugs/jacks.

On barrel, jacks, however, there IS no tip, so any switching must be done with the shaft/shank of the plug. To DO that switching, the plug needs to fit the allotted space snugly enough that it can move the little spring-leaf contact you can see from the outside out of the way. IF the wrong diameter plug is used, it can happen that there is enough wiggle room that the spring-leaf mechanism is not sufficiently dislodged by plug insertion, and there is no switchover from battery to external power.

Does this pertain to your DL-4? I doubt it because the unit is not battery-powered at all. On the other hand, do we know that the plug from the borrowed wallwart is making suitable contact with everything?

Just as an aside, my buddy Andy Harrison, who techs for Sheryl Crow's band, and is currently touring with the Foo Fighters as Dave Grohl's tech, recently recounted an incident where a particular circuit he had built simply would not give appropriate voltage readings. It was driving him nuts. He considered every plausible possibility and checked and rechecked. Turns out he had not considered the implausible possibilities. The battery had been assembled in a faulty manner, with the + and - terminals reversed. Who would have thought to blame the battery? He goes through thousands and this had never happened ever.

I guess this only goes to show you that you need to check EVERYTHING, even the most implausible scenarios.

[methodofcontrol]

thanks for the tip mark H., but i'm sure this is the larger barrel plug adaptor. i verified that before attempting to use it. i know a boss-style adaptor is slightly too small, (not to mention DC, and negative tip at that!)
i found some good C-cell batteries and tried the pedal that way, still no luck.
i've resoldered the power jack 3 times now, i did the input and output jacks, and i started resoldering some elecrolytics. the 1n4001 diodes seems fine. (not sure of that value, just a guess.....the 3 black diodes nex tto the jack)
i will retest them and repost thanks for the hlep guys.

[methodofcontrol]

i think i fixed it. i retested those black diodes, they seem fine. i decided to try the system reboot idea even though i didn't think the pedal was even working. (i initially wanted to get it to turn on consistantly before trying to reboot it)
anyway...i had some friends over for a jam tonight, and i had one of them plug in the input wire while i held down the A+D buttons. VOILA! the lights flashed and it came to life. (again). i unplugged it and rebooted 2-3 more times, and then i let my friend use it on guitar for about an hour. he went through every setting and looped a bunch of riffs as well. we didn't have a single issue w/ it all night. at the end of the night, i unplugged it and replugged it to make sure it would still work. i banged it around and hit all the buttons, it seems fine now. i guess the original problem was the power jack sodler-pads, and that led to some software malfunctioning. so now that solders have been retouched and software rebooted, i think i'm good to go. thanks to both of the marks for seeing me through this. i'll ressurrect this thread if i have anymore problems w/ it.

[Mark Black]

Cool - thanks for the follow-up! Hope that's the end of the problems...

Mark

[methodofcontrol]

another follow-up....
it's been over a week and the DL-4 has been used on 3-4 seperate occasions at volume w/ no problems what-so-ever. all delays and looping functions seem 100%.
although, for what it's worth, i prefer my AKAI HEADRUSH E2 for it's looping capabilities, except that the AKAI is not a true bypass pedal. win some-lose some.
thanks again for the help!

[joshcabob]

what if a factory reset doesn't work?

I have a DL4, and it worked great for a number of months, all of the sudden I was fooling with it today and messing in the reverse delay function, when it suddenly locked into that setting and I could change anything, so I unplugged it and then plugged it back in and it won't power on. I can't even get the factory reset option to get it to turn back on. It seemed to freeze as I was twisting some knobs in the reverse delay preset. I unplugged it while the guitar chord was left in the "mono/left input" and plugged the power supply back in and nothing came on. I tried the factory reset with both power out and guitar chord out and then reinserting them both but still nothing...