I got a free Boss DS-1 from the store where I do technician work today.  The customer brought it back in the with "it was broke when I got it out of the box" story.  It looks like it was connected to a reverse polarity power supply at some point...the entire side of the 1N4001 reverse polarity protection diode is literally blown off.  This definitely wan't broken right out of the box.  The pedal works in bypass mode and the LED works, but it doesn't work in effect mode.

This is one of the older units with the BA728N chips (as opposed to the newer ones with the Mitsu. M5223AL chips).  Could someone with a unit with this same chip take voltage measurements on the pins of the chip?  I just want to make sure that the chip isn't dead.  I'll also go through and test all the transistors, resistors, capacitors and diodes.

TIA
Phillip

QuoteYou mean it doesn't work after you replaced the diode?

Wait a minute, scratch that. It wouldn't work in any mode if you hadn't. My bad. :oops:

Regards

RDV

Actually, it worked in bypass mode with the diode blown out.  The diode is in parallel with the power supply, so it wouldn't have stopped the +9V from going into the circuit.  I did replace the diode with a new one, and it still isn't working in effect mode.  The solder joint on the ground pin (pin 4) of the IC was weak, so I resoldered it, but still no distortion.

Phillip