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Messages - Clyde

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Amplifier Discussion / Re: Seeking Roland Micro Cube Schematic
« on: April 22, 2018, 10:24:19 PM »
Roland seems to wants to deal with 'authorized service' shops and not so much with DIY repair.  At least with schematics and internal components/parts.  So... I ended up with this Alps 7 pos switch from Mouser.  Works perfectly.

There were also 2 ea 1K ohm 0603 SMD resistors that were open.  These were 2 of 8 located on the amp selector baby board that the switch was mounted on. Replaced same and all is well. 

Initial problem was only two of the amp select choices was working.  The above replacements corrected the issue.  But in poking around the rest of the amp I could not help notice the Alps pots are not held together by much.  Closer inspection led me to believe that this amp had been dropped on its top or stacked with something on top that placed pressure on the control knobs and pushed the back out of some of the pots (selector switch included).  I'll be replacing these Alps with something more robust. 

Amplifier Discussion / Re: Seeking Roland Micro Cube Schematic
« on: April 14, 2018, 02:42:52 PM »
Roland might.  I just have to wait for Monday when their parts dept opens up.  In the meantime I thought I'd ask around with the intent of going thru Mouser rather than Roland to get a replacement.

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:
or this:


Amplifier Discussion / Re: Pls help me fix Fender M-80 SS guitar amp
« on: June 11, 2017, 03:07:44 PM »
Google Drive seems to behave differently than other image hosting sites I've used. 

Experimenting around & using the following:

sticking that between <img> tags gets this:

Amplifier Discussion / Re: Pls help me fix Fender M-80 SS guitar amp
« on: June 10, 2017, 12:25:47 AM »
Interesting.  On my previous post the image showed in preview & after posting & I thought all was good.  Clear cache or try from another browser & blank goes the image.  Sorry about the dead end. 

Amplifier Discussion / Re: Pls help me fix Fender M-80 SS guitar amp
« on: June 09, 2017, 11:19:16 AM »

Don't know much about Google Drive...but clicking on the link brought up the image & rt click/copy image address & pasting between tags as Image Insert got me this.   Seems like there should be an easier way but at least the image posted.

Schematics and Layouts / Re: marshall G25r
« on: May 31, 2017, 10:46:06 AM »
The only help I can offer is:

G10R schematic (post#4)

Attachment is for G25RCD

Maybe enough info in these to get you where you want to go.

Amplifier Discussion / Re: Blackstar ID Core 40 'Bricked' Problem
« on: August 21, 2016, 10:32:51 PM »
Thanks for the comment Galaxiex.   Hopefully this might help others out there with the same issue.  There is hope.

Now if I can get a grip on the speaker problem I'll be 'done' with this.  If I prove it to the audio amp I'm not exactly looking forward to the replacement process. challenge trying to get it 'right'.

Amplifier Discussion / Re: Blackstar ID Core 40 'Bricked' Problem
« on: August 20, 2016, 05:52:15 PM »
It lives!
I was able to get my hands on a working IDCore 40 & after using Flashrom/Serprog to read the data on that amps serial mem chip & writing same to the 'dead' amp it powered right up.  That's the good news.

Bad news is that the speakers are stone dead.  But... the headphone jack & USB ports work as advertised, allowing me to run thru the various amp functions using headphones or into a PC/DAW.  Also was able to log into the Blackstar 'Insider' site & performed a successful firmware upgrade. 

For speaker output the amp uses a TDA7491HV 20+20w class D audio amp & from the datasheet it appears that it is stuck in standby mode with a ground sitting on stby & mute pins (PowerSSO-36 chip).  And reverse engineering this w/o schematic is problematic at best.  But I'm still chasing things.

All about tinkering & learning for me.

Amplifier Discussion / Re: Blackstar ID Core 40 'Bricked' Problem
« on: August 01, 2016, 12:23:17 PM »
Still in-search-of a Flashrom binary read of the data on the IC#2, M25P15 Serial chip from a working amp.  I know it's out there somewhere.  Same story:   the more I probe around on this board, the more convinced that flashing this sucker will give it a spark of life.  PWC does have JTAG connector points but I have yet to venture there.

Blackstar only has a few older firmware releases and they are only available in .exe format on their server thru their Insider app.  No binary file. 

I called Korg USA about this problem & even the possibility of a replacement pwc.  No replacement parts at all available for ID Core 40.  So this is truly a do-not-repair $200 item.  Sad to me. 

Amplifier Discussion / Re: Blackstar ID Core 40 'Bricked' Problem
« on: July 28, 2016, 10:26:55 AM »
Queries sent to Blackstar support remain unanswered.  I thought posting this problem on the Blackstar Forum might help.  Can't get a response from the forum admins to approve joining said forum.  Sent a query off to Korg parts supplier for Blackstar USA, seeking info.  No response.  Interesting, albeit frustrating. 

Any hope of getting a firmware ROM copy is fading completely.  Sure not going to buy a working one just to read the ROM.

Still plugging on this.  And the beat goes on...

Amplifier Discussion / Re: Blackstar ID Core 40 'Bricked' Problem
« on: July 23, 2016, 01:47:50 PM »
I've sent queries off to Blackstar regarding the problem.  Waiting for a response with less than great expectations. 

They had a repository of past firmware upgrade revisions but those files seem to have been removed from their site.  I still may seek out a user of a working amp that can get me a copy of the serial chip data & try to flash this dead one.

If this project stays bricked, it becomes a boat anchor.  For now it's still a good exercise for my gray matter.  It's a puzzle, a challenge, a chance to save something from the landfill and a cheap course.  These types of amps are not my idea of keepers.  If I want digital that requires a PC I use Kazrog, SGear or POD.  And the ss or tube amps that I do have are all old, simple & will last longer than I will.  And I agree about the 'all in one' stuff.  Apparently this is a good example.

Amplifier Discussion / Re: Blackstar ID Core 40 'Bricked' Problem
« on: July 22, 2016, 10:01:45 AM »
I appreciate the suggestions.  It's all worth a shot.  Thanks much.  I'll get back to poking around on this amp later today.

Amplifier Discussion / Re: Blackstar ID Core 40 'Bricked' Problem
« on: July 21, 2016, 10:39:21 PM »
I've followed Blackstar 'Factory Reset' (restore fact settings) by depressing Mod, Dly & Rev buttons simultaneously & turning pwr on.  No response.  Also tried depressing Manual & Mod buttons & powering up, which is supposed to force into update mode.  Again, no joy.  I tried all other combinations with the same result.

Checked the 12MHz oscillator after blowing dust out of my Tek 2235.  All there/all good.  I'm currently perusing the 159 pages of LPC4330 MCU datasheet & scanning the 1400+ pages of its users guide. 

Amplifier Discussion / Re: Blackstar ID Core 40 'Bricked' Problem
« on: July 21, 2016, 05:50:10 PM »
I'm not the original owner of this amp.  I recently picked it up for $30 USD from a seller who had no info other than it didn't power up.  According to my breakdown of the serial# it is of 2014 vintage.  No chance of warranty.

Of course I was hoping that his would be a power brick or fuse/open/short issue.  Not.  Input voltages at the various IC's read within tolerance per the datasheets...but w/o a schematic I am guessing.  But distribution is there.

The NXP LPC4330FET180...I've pulled a datasheet for that but it's a block of a ball array that sits atop the PCB with no way to discern what leads  go where.  Still looking at that.  I've yet to check for clocking.  I'll do that next.

I didn't believe that firmware issues could cause these symptoms, but researching common problems with these amps I found a number of complaints about identical symptoms caused by upgrades gone bad.  Peavey Vypyr too has had problems akin tho this as identified and corrected in This YouTube vid  All things being equal, I felt that this problem was inherent to the breed enough to where I took the firmware route as a path of least resistance approach.  Not the best troubleshooting approach but I'm flying a bit blind here.  I figured this was going to be a learning experience.  Not disappointed.  More like PC repair than I'm used to (see: hobbyist).

Thanks for the response guys.


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