Line 6 DL4 power problem

[jimosity]

I've got a DL4 that won't power up and tracking down the problem part is a nightmare.

I've replaced the 1n4002's in D12 and D11
I've replaced the MAX660, MAX887 and the component at D15 as well.

Using a continuity tester, I was getting a tone between the + and - of C58, so I tested that part and it tests fine out of the circuit, but shorts when back in -- I went ahead and replaced that anyway.
Same for R54 (1k) and C18 and C26.
That leads me to believe that I have a problem with U9 (817A power transistor), however I don't have that part available right now and would have to order it. I hate to order that part, just to be guessing.

Can anybody offer any more insight into how I can get this thing working again?
I saw a mention of using a 7806 in place of this ridiculously complex power section, but I'm not quite good enough yet to know exactly what to do to make that work.
Ultimately, if I could just replace all this mess and power it with a standard Boss 9VDC power supply; that's the goal.

[Enzo]

Hi Jim, welcome to the forum

I am not familiar wiht the unit, but I can say that for most of us, without a schematic, a bunch of part numbers doesn't mean much.

If this runs on a power adaptor, is it the factory one? What voltage doesn the unit say it wants? 9VAC 9VDC? 12v? If it wants 9VAC and you give it 9VDC, it won;t work.

In any case, if the proper power adaptor is used, then make sure that adaptor is actually producing the voltage it is rated for. Then connect it to the unit and see if that voltage is making it from the adaptor into the system.

ANd if so, at this point when I encouinter stuff witho9ut dociments, I check every damned diode in it. And transistors as well. I canp;t very well check power control ICs, but the simple stuff is really more likely the failure point.

[Mark Black]

Came across this a little while ago:

DL4 ps

Don't know if it's factory or a trace-and-draw but it's darn nice of the guy to post it!

Edit: You might also want to periodically try the "factory reset" procedure discussed here:

http://music-electronics-forum.com/t1119/

(Don't forget to plug a cord into the input to enable power-up - been there & done that)

[Enzo]

Cool, so it looks like it wants 9VAC. Looks like +9v would work, but a -9v Boss pedal adaptor wouldn;t make it past D11.

[CrassZ]

Line 6 DL4 Power problem(battery)

Can anyone help?

I have a Line 6 DL4 that worked with batteries when first purchased, but now (a year or two later) only works with an adapter plugged in. I have checked the continuity of the battery carriage to the circuit board and it is fine. My batteries are all juiced up. What could be the problem?

[52 Bill]

You probably have a problem with the switch contact on the AC adaptor jack. Clean it with some DeOxIt and check to see if it is loose from the circuit board.

[CrassZ]

Maybe I didn't express myself well---the AC adaptor works fine with the device(it provides power). But when I try to run the Line 6 DL4 on batteries, nothing happens.

[52 Bill]

You expressed yourself fine, I guess I didn't.

There is a switch contact on the ac adaptor jack that turns off the batteries when the adaptor is plugged in, this way the ac adaptor does not cause the batteries to heat up and explode.

If the switch on the jack becomes oxidized or dirty, the batteries will no longer re-connect to the circuit causing the symptoms that you described.

[novoros1]

Hi Jimosity, I have the same problem, tried the diodes they are OK all caps are OK but the unit still doesn't powers up. Have you be able to find the problem with yours. Any help highly appreciated.

[jrfrond]

The major issue here is that when a DL4 or any other similar Line 6 effect (MM4, etc.) powers up is that there is a whole microprocessor sequence that happens. You may very well have a solid power supply and have an issue with the microprocessor. Perhaps a dead clock, a missing reset pulse, no B+. Perhaps a bad tact footswitch stuck "on" and tying up a data line. Really, it could be anything.

As a Line 6 service center, we will go only so far and then replace the circuit board. We don't LIKE being board jockeys, but when it has to be repaired in a reasonable amount of time, it can be the only economical answer.

[davis1866]

I've got a used DL4 that operates seemingly fine but it has had a few glitches
once it locked up in loop, an other time one of the presets changed on it's own and reduced the output, one other time it malfunctioned and wouldn't turn on until factory reset. I've reset it 3 times on different occasions

I had a friend look at it and he said the D16 is bad (visually to him)
I've checked the diodes in the power section @ 2Mohm with a multimeter
D10 ~ .73
D11 ~ .83
D16 ~ 1.4

i have another broken DL4 (old version)
D16 reads nothing on both sides
D11 & D10 - .717 exactly

I was told both the D16s are not functioning properly (based on these values) and need to be replaced.
Any input would be greatly appreciated since i don't know what i'm doing. I was only instructed on how to isolate these diodes and test them and that the values I got were sound except for both the D16s

this is a similar issue and the most recent/active thread i could find, sorry if i'm out of place

[pierre]

i got my hands on a dl4 delay modeler...pluged it to a voodoo lab pedal power....9v . should the lights for the A.B.C and Tap TEMPO switches go on right away ?
got 4 fresh C batteries in it and same result...do i need to plug in my amp to make it work? since there is no off & on switch on any of this devices i dont want to take a chance and burn something...please help ..tx

[geektard]

I got a little 9v to 6v regulator (LM7806: Voltage regulator), alligator clipped it to the battery terminals and plug my normal 9volt power supply into it (a couple of battery adapters). I drilled a little hole and screwed the regulator to the heat sink part of the body to dissipate the heat from the regulator - otherwise completely reversible.

[dustartist]

If I wanted to check the voltages at the various points in the power section that have known voltages, where should I connect my meter to ground? The wall wart is delivering about 11v and I can use a DC power supply to put 6v on the battery terminals. I am supposed to get 3.6vdc after the zener diode w/ the power supply connected, and 6vdc w/ the battery I am guessing. The MAX887 can handle 3.5 to 11v, so I assume either voltage would work at the V+ of the MAX887. I think I must have my meter connected to ground wrong, because I am not getting anything at the V+ of the MAX887 even with 6vdc connected to the battery terminals. Any ideas would be greatly appreciated...

[Jazz P Bass]

The 'ground' connection would be the - of the battery.