GR-55 - "Inside view of the GR-55"

Started by gumtown, February 26, 2011, 10:47:10 PM

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gumtown

Here are some snaps of the GR-55's guts..



Two board assembly with the footpedal/buttons/display board on the bottom and the main CPU and I/O board on top.


the two boards at a bit of an angle.


here is the CPU, RAM and DSP


this is the mysterious unused CN-7 connector


the rotary encoder used for the EXP pedal.
Free "GR-55 FloorBoard" editor software from https://sourceforge.net/projects/grfloorboard/

gumtown

The two VHC 574 chips connected to CN7 are octal flipflops, my guess is they were originally going to used a couple of 7 segment led displays for displaying the patch numbers like on previous equipment.
Free "GR-55 FloorBoard" editor software from https://sourceforge.net/projects/grfloorboard/

ddlooping

Quote from: gumtown on February 26, 2011, 10:51:13 PM
The two VHC 574 chips connected to CN7 are octal flipflops, my guess is they were originally going to used a couple of 7 segment led displays for displaying the patch numbers like on previous equipment.

Aren't octal flipflops normally used to go to fractal beaches?  ???
Diaz Guitars (work in progress)

aliensporebomb

Anyone have a similar breakdown of the VG-99?  Interesting!
My music projects online at http://www.aliensporebomb.com/

GK Devices:  Roland VG-99, Boss GP-10, Boss SY-1000.

Gastric

It looks like there's tons of room in the chassis. Seems you could install a couple switched 1/4" jacks into the chassis and hijack the 13 pin input for a guitar pickup affects loop.

ddlooping

Quote from: Gastric on March 03, 2011, 01:59:23 PM
It looks like there's tons of room in the chassis. Seems you could install a couple switched 1/4" jacks into the chassis and hijack the 13 pin input for a guitar pickup affects loop.

... and some foot switches for S1/S2 as well. :)
Diaz Guitars (work in progress)

FrankG

Wow look at those VLSI packs... I was expecting a pair of SN76488N from Radio shack... :)


the power to do nothing is tremendous, but it must not be abused...

drjoness2001

It looks like the GR-55 could be a candidate for a Richard McClish designed input filter board, which helped the VG-99 work much better with piezos and such.

gumtown

Quote from: drjoness2001 on March 15, 2011, 11:02:34 PM
It looks like the GR-55 could be a candidate for a Richard McClish designed input filter board, which helped the VG-99 work much better with piezos and such.
Here is the topic on that https://www.vguitarforums.com/smf/index.php?topic=3236.0
Free "GR-55 FloorBoard" editor software from https://sourceforge.net/projects/grfloorboard/

Elantric

#9
Hopefully Richard will complete this task soon, and return my GR-55 being used as the "test ginea pig" for the new GR-55 subsonic filter board.

QuoteAnyone have a similar breakdown of the VG-99?  Interesting!

Inside the VG-99
https://www.vguitarforums.com/smf/index.php?action=dlattach;topic=28.0;attach=965

antoinebab

Did Someone already try to install a Jack input to use the gr55 as an usual pedalboard ?

Elantric

QuoteDid Someone already try to install a Jack input to use the gr55 as a usual pedalboard ?
Look here:

https://www.vguitarforums.com/smf/index.php?topic=4624.msg31179#msg31179

WV

Quote from: ddlooping on March 03, 2011, 02:08:26 PM
... and some foot switches for S1/S2 as well. :)

Yes!  Please!!!
Loaded 2012 Mac Mini, OSX 10.10.5, Logic 10.2, DP8.x, Cubase8.x, Godin LGX-SA+MIDI Guitar App+ Boss GP10, JTV59+FTP,

paults

Quote from: WV on October 08, 2011, 09:11:14 AM
Yes!  Please!!!

Drill one hole - install a tip ring sleeve 1/4" jack.  Connect a wire from the Tip to 13 pin connector wire 10.  The ring gets wired to connector wire 11. Ground the sleeve.     

DONE :) 

Or, Look for the "Magic Box" thread.  Foot switches for s1/2 would be a simple addition to one of those.

   

WV

Quote from: paults on October 09, 2011, 07:29:54 AM
Drill one hole - install a tip ring sleeve 1/4" jack.  Connect a wire from the Tip to 13 pin connector wire 10.  The ring gets wired to connector wire 11. Ground the sleeve.     

DONE :) 

Or, Look for the "Magic Box" thread.  Foot switches for s1/2 would be a simple addition to one of those.

   

Just bookmarked it!

Thanks ;)
Loaded 2012 Mac Mini, OSX 10.10.5, Logic 10.2, DP8.x, Cubase8.x, Godin LGX-SA+MIDI Guitar App+ Boss GP10, JTV59+FTP,

mbenigni

I'd be curious to hear whether/ to what degree the GR55 will function with some of those ribbon cables disconnected.  I'm thinking of trying to make a smaller lightweight version by taking it out of the chassis and relying - when needed - on external footswitches.  I've found the switches and footswitches on the GR55 itself to be too limited in their applications, and they're just not worth the real estate.

I'm guessing the mainboard will still run and function with the expression pedal detached (ironically, one of two devices whose real estate is justified IMO - the other being the CTL pedal), but getting free of the patch 1/2/3 pedals etc. might get a little sketchy.  The smaller PCB appears to have a lot intelligence built in beyond just managing switching and I/O.

I'll have to do some experimenting, but if anyone's already gone down that road and can save me the time (or the risk), all the better!