Boss DS1 switching?

brokenstarguitar · February 09, 2016, 01:42:05 PM

I have a Boss DS1 that I modded. Somewhere something went wrong and I wasnt getting anything out of it. I found the issue to be D1, the diode that connects the Power jack to CLR (R35) for the led. It switches on and off (9 out of 10 times)but my led isnt powering. I checked the led off the board and its good. I also took R35 off and that tested good too. Now I believe the issue is the switching circuit, something I have no clue about. Can anyone explain or post a layout? The schematics dont have the input/output buffers and the switching. Any help is appreciated. Thanks!

Kevin Mitchell · February 09, 2016, 01:54:41 PM

I suggest you give information about what mods you have or were working at.

I also suggest you check out the switch and FETs Q6, Q7 and Q8 if you think it's a bypass issue. Be sure to check all connections you have tampered with.

I grabbed this schematic quickly to take a look for you. I wouldn't know how accurate it is to your pedal.

brokenstarguitar · February 09, 2016, 02:06:23 PM

This is the mod I did......
http://www.diystompboxes.com/smfforum/index.php?topic=106243.0

Ive done a few before without any issues. Ive been looking through the wampler book cuz he explains the circuit in detail but it still isnt helping. Ive went over all my connections with a continuity test and were good to go. Im going to check the Fets now. Hopefully this fixes it.

slacker · February 09, 2016, 02:15:42 PM

According to this schematic http://rh-tech.org/public/Boss_DS1_PG2.jpg the diode connected the R35 is a zener diode, this works like a normal diode in the forward direction but in the reverse direction like it's connected in the schematic it drops what ever voltage it's rated for, possibly 5 Volts. If there was a problem with it and you replaced it with a normal diode the LED won't work, because a normal diode doesn't let current flow in the reverse direction. You should just be able to replace it with a jumper and the LED will work, it will just be brighter than it used to be.

brokenstarguitar · February 09, 2016, 03:25:10 PM

Quote from: slacker on February 09, 2016, 02:15:42 PM
According to this schematic http://rh-tech.org/public/Boss_DS1_PG2.jpg the diode connected the R35 is a zener diode, this works like a normal diode in the forward direction but in the reverse direction like it's connected in the schematic it drops what ever voltage it's rated for, possibly 5 Volts. If there was a problem with it and you replaced it with a normal diode the LED won't work, because a normal diode doesn't let current flow in the reverse direction. You should just be able to replace it with a jumper and the LED will work, it will just be brighter than it used to be.

You sir are a genius. Works like a charm. Is there a downside not having that zener in?

Kevin Mitchell · February 09, 2016, 03:42:17 PM

Quote from: brokenstarguitar on February 09, 2016, 03:25:10 PM
You sir are a genius. Works like a charm. Is there a downside not having that zener in?

It depends on the rating of the zener. We'd guess 5.1volts "1n751" in the schematic which is common in many 9 volt projects. I wouldn't be worried about it due to the resistor there.

If you must (which I would do myself) radioshack sells those diode by the couple. I grabbed some last week. Just a suggestion if it's possible for you.

ElectricDruid · February 09, 2016, 05:16:24 PM

Nice work, Slacker.

T.

duck_arse · February 10, 2016, 09:42:46 AM

the zener also works as a low battery check. it won't conduct in that direction if the battery voltage is too low, so you get no light from the led, and change the battery, even though the pedal might still be working.

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Boss DS1 switching?