Boss DS-1 troubleshooting

[Renegadrian]

Hi there, I just got a DS-1 on repair...M5223AL inside...
voltage diode war burnt, changed it but no changes, led lits but no sound...what should I check!? transistor, M5223AL?!

[armdnrdy]

Use this to check voltages.

http://cdn.tonegeek.com/wp-content/uploads/Boss-DS-1-schematic.png

[Renegadrian]

THX Larry

according to the schem I have all the right voltages...

battery            9.02
r2              4.48
q1 C                 9.02
r4              4.48
r5                     4.48
r8                     9.02
r10                   4.48
m5112al pin 8   9.02
d4-d5               4.48
r19-r20             4.48
q3 C                 9.02
c23                   9.02
r24-r25            4.48
d2               9.02
r30-r31       4.48
R36               9.02

[armdnrdy]

Do you get bypassed signal bypass with the switch?

If so, I would audio probe the circuit to find where the signal stops.

If you had to replace the diode, that sounds like someone plugged in the wrong power supply and "toasted" a component.

[GibsonGM]

Maybe a switching FET?  Just a really dumb guess since the Boss switching is kind of Greek to many.   +1,000 on the audio probe.

[Renegadrian]

Yeah I think that one of these components toasted...I'll audio probe tomorrow...thx for now...

[GibsonGM]

R.G. has an article on the switching at GEOFEX....one of these days I'll get one to work, never could when I tried to DIY one.

[Renegadrian]

UPDATE: Audio probed it, the signal stops at pin 3 of the M5223AL, which is the input, it should exit from pin 1 but no signal...Guess it's the SIP then...

[armdnrdy]

So you have signal at the input of U1A? (Pin 3, R39, D8)

Check that D8 is good.

[Renegadrian]

changed d8, still the same, no sound from the chip output

[armdnrdy]

Well...It looks like you need to replace the op amp.

If you can't find a M5223AL, you can make a daughter board for a replacement. Look through this thread for some op amp ideas.

http://www.diystompboxes.com/smfforum/index.php?topic=66209.0;wap2

[Renegadrian]

it seems there are some on aliexpress. I'll take one there...

[Renegadrian]

I bought the chip on aliexpress, 3 weeks wait...new chip new life...
another ds-1 got the chip burned, I built a small adapter and put a tl062 in it, not bad.