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Topics - Clyde

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Amplifier Discussion / Seeking Roland Micro Cube Schematic
« on: April 14, 2018, 12:30:26 PM »
Anyone have anything on a Roland Micro Cube COSM ( discontinued early model w/o the i-Cube link feature)?  Roland doesn't want to share with non-authorized folks & I can find nothing on the web.

I have one of these that has as bad amp selector rotary switch (internal contacts broken).  Trying to locate a replacement but the only markings on the existing switch is the maker 'Alpha' with '4J1' stenciled on the back.  Anyone have a part # for a potential replacement?  Amp has 7 'amp sim' positions, so I am guessing that a 7 pos replacement like this one might work:
http://www.alps.com/prod/info/E/HTML/Switch/Rotary/SRBV/SRBV170501.html
or this:  https://www.mouser.com/ProductDetail/105-SR1712F-16NS

Thoughts?

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Amplifier Discussion / Blackstar ID Core 40 'Bricked' Problem
« on: July 20, 2016, 05:14:59 PM »
I'm looking at a Blackstar ID Core 40 that will not power up.  It uses an external laptop type power supply & it's putting out 16vdc to the PCB.  I do not have a schematic for this unit and doubt I'll ever see one given Blackstar's policies.  So I'm pulling data sheers for the various IC's & checking voltages.  Eyeballing the board reveals no obvious issue.

But...I'm reading that a few other folks have experienced dead/brick problems with this line after performing firmware updates via the 'Insider' software app that Blackstar has.  It allows access to patches & a bunch of features but also checks for & installs firmware releases.  Like other firmware updates, if they do not go in perfectly they can cause a total lack of communication & indications just like no power.

Has anyone had any experience with this firmware issue?  The microcontroller on this is a LPC4330FET180...180 ball array that I am not even close to being at home with.  Should I consider this a 'brick' and sell it as wall art or is there a path to repair?  Past experience with the USA distributor and parts supplier tells me that a replacement PCB would be difficult to obtain as well as costly. 

Just looking for thoughts and direction.  This project has me in the deep end of the pool.


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Amplifier Discussion / Marshall 3005/Lead 12 Power Trans Question
« on: June 16, 2015, 06:41:20 PM »
Looking at replacing a transformer on a Marshall 3005.  Can't find any info on the original tranny.  Only mark on it is 'T4942'.  Per available schematics this matches & breaks down to a 115VAC with a CT 28VAC (14.3 per side...so 28.6) secondary.  Input also indicates 35w & 40VA.

The closest thing I can find as a replacement is from Hammond:  either their p# 166J28, which is a 1A, 28VA unit, or p# 166L28, which is a 2A, 50VA unit.  My 1st inclination is to go with the larger VA rating rather than undercutting.  The smaller rated unit will match for size but there's room enough for the larger. 

Am I thinking this through properly?  Any thoughts would be appreciated.

C

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