Delay broke, looking for schematic.

[jondoeband]

Hi.

I am looking for the schematic of a Washburn A-AD9 Analog Delay or a similar pedal.  The pedal crapped out on me today, and when I took a look inside, a resistor had melted.  As that is the case, the resistor is unidentifiable.

Also, what would be a good way to remove said melted component?

Thanks in Advance!

[Dan N]

I think a certain era of Washburn pedals were made by a company that pumped out pedals with a bunch of different names. Washburn, Electra, Epiphone, Martin Stinger, etc... Maybe your falls in this period? Are all the leads along the side?

I once traced out a Martin. Colin hosts the schematic at his site. Maybe he won't mind a direct link?

http://experimentalistsanonymous.com/diy/Schematics/Delay%20Echo%20and%20Samplers/DE-80.gif

My Epiphone is pretty much the same except uses MN3205 and MN3102.

Removing the burnt resistor?  I'd snap it in half with nippers, bend the ends up, heat the pads and pull up. Use a knife to scrape off the carbon residue on top. Viola.

[jondoeband]

Thanks for the schematic.  Unfortunately, when I took out the part, it turned out to be something other than a resistor, but it was the source of the problem.  it is a component that is now colored black and grey, slightly smaller than a resistor, and has the code 
GI-50 imprinted on it.  Any clue as to what this might be?   I'll try to post a pic later.

[jlullo]

could it be this? (photo diode)

http://www.alldatasheet.com/view.jsp?Searchword=NDL5461P

[tiges_ tendres]

I have one of these that went belly up too.  I could never even find more than a crappy web photo, let alone a schematic.

[jondoeband]

could it be this? (photo diode)

http://www.alldatasheet.com/view.jsp?Searchword=NDL5461P

No, its not a photo diode.  Here's a pic:http://i6.photobucket.com/albums/y226/jondoeband/Gear/part.jpg

I'm linking to it because its a bit large.

Pics of Circuit board are here:
http://i6.photobucket.com/albums/y226/jondoeband/Gear/DelayCircuitboard.jpg
http://i6.photobucket.com/albums/y226/jondoeband/Gear/Delaycomponents1.jpg
http://i6.photobucket.com/albums/y226/jondoeband/Gear/Delaycomponents2.jpg

I did a little clean up, and the red circled areas are where the part was.

[tiges_ tendres]

mine is differnet from yours,  mine has an mn3102.  but if it helps, the resistors around that chip are:

brown black orange 10k
red red orange 22k
red red yellow 220k

that should get you in the ball park

[Dan N]

That's almost exactly like the Stinger DE-80. I think the NE571 is an upgrade over the NE570. Your burnt part is a 1N4001 diode, unmarked in the bottom left part of the schematic going from 9 volts to ground.

Here's a cartoon of the Stinger board:

http://experimentalistsanonymous.com/diy/Schematics/Delay%20Echo%20and%20Samplers/DE-80%20board.gif

[analogguru]

It is a (normal) diode, replace it with a 1N4001, 1N4004, 1N4007 or similar

analogguru

[jondoeband]

Cool.  Thanks guys.  now all I should have to do is get the part.  Gotta get the cash first. . . It sucks being a poor college student
maybe I can find something in the old TV I just took apart.
Thanks Again!

[analogguru]

It should work without this diode. The diode is only used as a protection against reverse polarity from the ac-adapter.

analogguru

[jondoeband]

After removing the Diode and replacing a bad wire from the input jack to the board (the lose one in the pics) I plugged it back in and tried out the pedal, and ran into some new problems.  First, there was a weird buzzing noise that kinda sounds like a small engine or a Helicopter blade from a distance. second, the delay repeats are not as pronounced as they where (I had the pedal set up for a Buckethead Big Sur Moon type delay)

Any Idea what I did wrong?

[guitar_199]

I may be off base but I thought I'd ask:  are you feeding this with a battery or a wall wart?   If a wall wart... is it a DC or an AC wall wart?

That power conditioning in the schemo is DC voltage divider stuff only....meaing it needs to be fed with a 9v DC wal wart.

[Jaicen_solo]

Looks to me like the diode failed because of reverse polarity across it.
I suggest you first check your PSU, and try running the pedal on a fresh battery and see how well that works.
I actually have a DD-2, which is digital so not directly comparable, but it doesn't work with PSU's that aren't properly regulated, so that might be a good place to start looking.

[jondoeband]

guitar_199: I am just running a 9 volt battery.

Jaicen_solo: PSU?
I haven't really done much to the actually unit until now.  Before this I had just replaced a bad 9 volt clip with a new one from radio shack, and haven't had any problems up to this point.

I may have found part of the problem to be a poorly soldered wire (the one that I replaced).  I'll fix this first and see what happens.

[puretube]

PSU = power supply unit;

in this case: "wallwart" with DC output...