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DIY Stompboxes => Building your own stompbox => Topic started by: Luqqas on November 11, 2012, 08:17:33 PM

Title: Anybody with a BOSS LMB-3
Post by: Luqqas on November 11, 2012, 08:17:33 PM
Hi! Please take a look to this picture. It's super simple if you have one.

It's a BOSS LMB-3 (Bass Limiter Enhancer)

(http://img32.imageshack.us/img32/1228/lmb3e.jpg) (http://imageshack.us/photo/my-images/32/lmb3e.jpg/)

Uploaded with ImageShack.us (http://imageshack.us)

Uploaded with ImageShack.us (http://imageshack.us)
Can't anyone with this same unit tell me wich type and code of transistor is?
On PCB is labeled as Q11.
It has blown up literally and no chance to get even the name to replace it.

Thanks!
Title: Re: Anybody with a BOSS LMB-3
Post by: Luqqas on November 13, 2012, 01:03:45 PM
Please... no one?
Title: Re: Anybody with a BOSS LMB-3
Post by: RandomGlitch on November 13, 2012, 07:40:12 PM
If it was me and I didn't have a schematic or other info, I'd just desolder the transistor, replace it with 3 pin sockets and try various transistors, starting with a 2N5088.

But, yeah maybe someone has one and will help you more specifically. I looked for a schematic online, but could not find one.

Good luck! :)
Title: Re: Anybody with a BOSS LMB-3
Post by: Crontox102098 on November 13, 2012, 07:50:40 PM
why it burned?
Title: Re: Anybody with a BOSS LMB-3
Post by: Luqqas on November 14, 2012, 10:40:53 AM
Quote from: RandomGlitch on November 13, 2012, 07:40:12 PM
If it was me and I didn't have a schematic or other info, I'd just desolder the transistor, replace it with 3 pin sockets and try various transistors, starting with a 2N5088.

But, yeah maybe someone has one and will help you more specifically. I looked for a schematic online, but could not find one.

Good luck! :)

Thanks for your reply. It's a good idea. I've also tried looking for schem, but only LMB-2 it's available and it's really different with this version.
Title: Re: Anybody with a BOSS LMB-3
Post by: Luqqas on November 14, 2012, 10:43:26 AM
Quote from: Crontox102098 on November 13, 2012, 07:50:40 PM
why it burned?

a friend of mine connected those crappy cheap multi-voltage PSU and polarity was with center positive. After a few seconds, melted.
Title: Re: Anybody with a BOSS LMB-3
Post by: armdnrdy on November 14, 2012, 11:45:47 AM
I looked through several Boss schematics and it seems that there's a constant in their designs. I usually saw a NPN transistor in the front of the circuit. This transistor was always of the 2SC variety which will have a pinout of emitter, collector, base.

Try a 2SC1815 if you have one. If not try a 2N3904 or 2N5088 but strip some insulation from 22ga or larger wire and insulate the legs of the transistor that you have to cross to accommodate the ECB pinout.

I hope this helps!
Title: Re: Anybody with a BOSS LMB-3
Post by: analogguru on November 14, 2012, 02:41:00 PM
It´s probably a PNP-transistor used for the Vref.  Why don´t you take some additional pictures so that the schema can be traced ?

analogguru