| Author |
 Topic  |
|
Mesjoggah
Gold Member
Netherlands
595 Posts |
 Posted - 01/18/2009 : 18:23:11
|
 |
 |
|
|
Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 01/19/2009 : 01:13:50
|
I'm not ignoring this thread... I'm a bit stuck. Have a few ideas I'm looking into - will post more when I have more to say...
|
|
|
|
Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 02/03/2009 : 18:15:46
|
The final note in this saga... and a cautionary tale about schematics from the internet 
Mesjoggah's ODB-3 is currently on a skiing holiday here in Canada 
When I set up the test gear I knew it had to be something "basic" and indeed it was. It turned out that the Vref (the 4V rail) was faulty. I didn't ever think to check that when we were doing remote trouble-shooting because it was "just a couple of divider resistors" according to the schematic (this arrangement almost never fails). WRONG. The actual circuit has an NPN transistor supplying the divider resistors (for stabilisation) which is not shown on the schematic - ie the schematic is incorrect.
The correct arrangement can bee seen on the BD-2 schematic if you have it (minus the opamp buffer).
Anyway, the NPN transistor had failed, giving 1V on the 4V rail. With only 1V for Vref, bad things happen - FETs don't switch, gain stages choke, all the things it was doing.
Replaced the dead transistor and viola, all is well.
|
|
|
|
Dirk
Platinum Member
Netherlands
1309 Posts |
Posted - 02/03/2009 : 18:24:53
|
So because someone supplied a faulty schematic, Mesjoggah actually had to send a pedal halfway around the world so you could replace some dumb transistor?
Haha, what a joke.....not.
Nice to hear that at least it's working again. |
|
|
|
Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 02/03/2009 : 18:34:35
|
Nope - it's my fault for not thinking to ask for this to be checked.
I'll be posting a corrected schematic once I get it redrawn.
The good news is... Mesjoggah asked me to mod it for him as part of the work, so now he has a very special "Laurie pedal"... 
And... I made it sound simple, but it took three (3) hours to deduce what was happening, trace the new schematic, find and replace the faulty component, and tidy up the pedal (reterminate the wires because they were tired from the board being swung in and out, etc.).
|
|
|
|
Mesjoggah
Gold Member
Netherlands
595 Posts |
Posted - 02/03/2009 : 20:55:16
|
quote:
Originally posted by Dirk
So because someone supplied a faulty schematic, Mesjoggah actually had to send a pedal halfway around the world so you could replace some dumb transistor?
Haha, what a joke.....not.
Nice to hear that at least it's working again.
Well, since two pedals ship for the same price as one i threw in a broken DD-3 as well, if Laurie can fix this too the costs per pedal will be lower while the value has been raised |
|
|
|
Mesjoggah
Gold Member
Netherlands
595 Posts |
Posted - 02/05/2009 : 19:07:49
|
quote:
Originally posted by Laurie
Nope - it's my fault for not thinking to ask for this to be checked.
I'll be posting a corrected schematic once I get it redrawn.
The good news is... Mesjoggah asked me to mod it for him as part of the work, so now he has a very special "Laurie pedal"...
And... I made it sound simple, but it took three (3) hours to deduce what was happening, trace the new schematic, find and replace the faulty component, and tidy up the pedal (reterminate the wires because they were tired from the board being swung in and out, etc.).
Laurie, how does the modded one sound compared to your stock one? |
|
|
|
Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 02/05/2009 : 19:16:38
|
quote:
Originally posted by Mesjoggah
Laurie, how does the modded one sound compared to your stock one?
I didn't dig out the bass head and 4x10 but with a guitar into the clean channel of a marshall, the modded one is a little louder with more grit. Not a huge difference, but clearly different.
|
|
|
|
Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 03/17/2009 : 18:08:46
|
| G'day! This should almost be back to you now (by slow boat). Be interested to hear how it all sounds |
|
|
|
Mesjoggah
Gold Member
Netherlands
595 Posts |
Posted - 03/18/2009 : 14:47:24
|
They haven't arrived yet Laurie, i suppose you went for the cheapest way and they send out a courier with a canoe!
I guess he should be halfway by now..
Just kidding, i hope they will arrive this or next week before i start worrying.
|
|
|
|
Mesjoggah
Gold Member
Netherlands
595 Posts |
Posted - 03/22/2009 : 08:46:08
|
quote:
Originally posted by Laurie
G'day! This should almost be back to you now (by slow boat). Be interested to hear how it all sounds
The're back!! they had the time of their lifes! went to Canada by plane, had a refreshing stay in some kind of spa/beautyshop/healthclinic/Laurie's place and came back on a six week cruise!!
Laurie, the pedals sound great, although i have no comparison for the modified ODB i do like the way it sounds. The DD-3 sounds more analog with the hi-cut mod, i like that too. I can't say much about the loop mod as i simply didn't have much time yet to fiddle around with it a lot, had to go to town first to buy me a TRS cable. If i'm lucky i can play with it today.
Once again; thank you Laurie! you've been a great help
|
|
|
|
Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 03/22/2009 : 09:19:47
|
Hi Mesjoggah
That's great news.
Laurie is a fantastic Eng-Tech, & is honest, as the day is long.
If you remember, Happypluckers CE-2 had a similar, but longer vacation, with all his CE-2 cousins in my workshop in Australia.
Regards Dr. Bob |
|
|
|
Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 03/22/2009 : 16:10:33
|
quote:
Originally posted by Mesjoggah
The're back!! they had the time of their lifes! went to Canada by plane, had a refreshing stay in some kind of spa/beautyshop/healthclinic/Laurie's place and came back on a six week cruise!!
Laurie, the pedals sound great, although i have no comparison for the modified ODB i do like the way it sounds. The DD-3 sounds more analog with the hi-cut mod, i like that too. I can't say much about the loop mod as i simply didn't have much time yet to fiddle around with it a lot, had to go to town first to buy me a TRS cable. If i'm lucky i can play with it today.
Once again; thank you Laurie! you've been a great help
That's awesome! I'm very glad you are happy with them!
PS: thank you for the kind words Dr. Bob... I'm blushing  |
Edited by - Laurie on 03/22/2009 16:11:11 |
|
|
|
Topic |
|
ODB-3 troubles
