Line 6 DL4 Powering issue

[michael_krell]

I have recently acquired a Line 6 DL4 that has some issues powering up. I took it all apart yesterday and started testing. I am getting power to the board and as far as I can trace.

One thing that I have noticed is that there is a relay located near the L (MONO) Input. I am assuming that this relay should come on when the 1/4 cable is inserted, although i am not completely sure of this.

I placed a meter across the coil of the relay and without the cable in there is little to no voltage. When i insert the plug i see about 1.5V across the coil. Could the coil not be getting enough voltage? I am using batteries to power this at the moment because i don't have a fancy Line 6 9VAC charger.

Does anyone have a schematic for this thing? I know Line 6 is not very helpful when it comes to this stuff, but I am sure someone out there has a schematic. Please help.....

[michael_krell]

I think I made some discovery here. Here is the datasheet for the relay

http://www.nec-tokin.com/english/product/pdf_dl/mini_data/relay_EA2_EB2_e.pdf

Its a single coil latching type. When the coil voltage is applied it latches one direction, when the polarity is reversed it latches in the other. When i apply 3v to the coil it Sets. When i reverse that voltage it does nothing. When i do the same thing on the other relay it sets and resets as the datasheet shows. Does this make sense to anyone? What could the problem be?

[michael_krell]

Ok, so I believe I had made some progress here. I think I have detected an issue with the power section, but I am not 100% sure. The are where I am seing something tricky is with the MAX887H DC-DC converter. Here is a schematic (hard to read) of the power section:

http://www.aronnelson.com/gallery/main.php/v/MrHuge/Line+6/DL4_ps.jpg.html

You can see the 6VDC supply goes directly to the MAXIM MAX887H DC converter. Then after the inductor the Voltage should be 3.3VDC. THis can also be confirmed by looking at the datasheet for the MAX887H which is here:

http://www.digchip.com/datasheets/download_datasheet.php?id=627191&part-number=MAX887H

The actual voltage is between 1.9V and 2.0V. So it makes sense to me that the problem is either in the circuit that converts the voltage from 6V to 3.3V, or maybe there is excessive load somewhere after the 3.3V that is pulling the voltage down to 2.0V. I checked out the votlage doubler circuit and it is doubling the voltage (2.0 to 4.0)

I am sure this troubleshooting would go much quicker with a schematic, but I am certianly making a lot of progress with the schematic of the power section. Any comments or help anyone can offer would be appreciated.

[michael_krell]

So! I have located the problem. There is a 80C32 microcontroller that seems to have a short between the Vcc and the GND pin. So obviously the chip is shot. Now the question is where do I get a replacement? This my first attempt to desolder a surface mount chip. I think it went pretty well.




So now that I have the chip off I need to know where to get a replacement. I guess a more important question is if this chip requires reprogramming. I cant imagine it does since the pedal does have an EEPROM. Maybe its time I got a reply.

[michael_krell]

Alright well i just spoke with Line 6 today and they are sending me a new chip at no cost.   

So I will report back if i got this thing working.

Kind of odd that I have not received one reply on this topic.

[snap]

obviously a Philips logo on that chip, now NXP, googled up on page1.
non-ROM P80C32SBB B
http://www.nxp.com/acrobat_download/datasheets/80C31_80C32_1.pdf
80C32
this will go even higher than 16MHz
http://uk.farnell.com/3166004/semiconductors-integrated-circuits/product.us0?sku=nxp-p80c32ubaa
but you will have to find one in a SOT307-2 pack.

[michael_krell]

Wow thanks for the reply!

I noticed that this is for a PLCC package. Will it fit on this QFP layout?

[michael_krell]

Welp through in the new chip fixed up some cut traces and this baby works.

I couldnt be happier

[snap]

Congratulations!