Guitar synth fails self test

[glen]

Hi folks,I have a guitar synth that is acting strangely.Did the internet searches for the usual suspects and eventually came across it's "service notes".In the "notes" which doesn't cover much I found that the unit can perform some self tests so I ran them and believe it was test #3 that it did not pass.Anywho the test is to check midi output(the unit acts irratically ,sometimes some strings won't sound,sometimes they all do,but the vol is always so low that I have to run the the guitar and the amp almost wide open and it's still not enough volume).The service notes do list 2 ic's to check but I cannot locate them on the block diagram or the parts list.there are not a lot of ic's in this(maybe 10)so I am wondering if there is some way to check the ic's in this unit and maybe find the culprit.Must warn you that I know next to nothing about electronics(I do have a multi-meter tho if that helps.Also my brother does electronic repairs but he is very busy guy so seeing if I can sort this myself.Appreciate any info or advice,thanks,Glen.

 

[kellys_eye]

Let me guess........ hmmmmm.......... nope, my crystal ball fu is none existent tonight. It seems there's absolutely no way I can detect the make, the model, the schematic or the board layout no matter how I throw my Tarot cards down......

 

[glen]

lol,yep I asked for that.I have tried to attach the service manual but it won't let me,says the file is to big(it's a little over 5mb)Here is a link to it tho. https://soundprogramming.net/manuals/guitarsynth/Roland_GR-30_ServiceNotes.pdf

 

[kellys_eye]

This is the proper link:

https://soundprogramming.net/guitar-synthesizers/roland/roland-gr-30/

Scroll down to the right part then you have to right-click and 'save-as' to get it. Else it returns you to the main page

 

[kellys_eye]

Test #3 relates to the MIDI functions - did you 'loop through' the MIDI in/out ports?

 

[kellys_eye]

there are not a lot of ic's in this(maybe 10)

I get to at LEAST 45 IC's.......

 

[kellys_eye]

but the vol is always so low that I have to run the the guitar and the amp almost wide open and it's still not enough volume

Have you checked your leads?

 

[(*steve*)]

Hey, they actually give you a schematic. That's impressive!

 

[kellys_eye]

Their keenness to supply schematics is inversely proportional to the chances of you fixing it.

 

[73's de Edd]

Sir glen . . . . .

If all of the Rockin' Rolands very special bells and whistles operate and it's just very low audio . . . . . .

All roads tend to lead to Rome . . . . and to Adobe page 14 and its IC46 . . . . .TDA1313T . . . with its inputs and outputs and as to to whether Q24, 25 and 29 mute transistors might possibly be having an unwanted base bias, presently being upon them.

73's de Edd
.....

 

[glen]

thanks for all the comments everybody,pretty clear that this is way over my head.Believe I will have to bug my buddy with electronics repair background.At least I can give him a good start as to what to look at.If my bud can fix this I will post back exactly what he had to do in case someone else runs into this it may help them out.thanks again will be in touch,Glen.