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MIDI Sound module no output.

roughshawd

Jul 13, 2020
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This is probably the most intricate board I have ever seen. It is a Roland MT-32 multi-timbre sound module. It has no output. So my first test should be the cabling, but the cables I used are good, I'm sure. .. ... . So assuming something in the output is failing, I suppose I should test the board for bad connections, the magnifying image is the output section on the board.
 

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roughshawd

Jul 13, 2020
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First question, the power supply is a labtec, 9v negative tip, that i scrounged, the Internet says its replacement is 1.2 a
Is 1200ma. Mine is 1000ma. Could the lack of .2 amps cause the output problem?
 

roughshawd

Jul 13, 2020
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What's the chance of finding data on this board?
 

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Delta Prime

Jul 29, 2020
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I'm on a stupid phone can't read the numbers they're upside down can you just write them thank you
 

Bluejets

Oct 5, 2014
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Last edited:

kellys_eye

Jun 25, 2010
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First question, the power supply is a labtec, 9v negative tip, that i scrounged, the Internet says its replacement is 1.2 a
Is 1200ma. Mine is 1000ma. Could the lack of .2 amps cause the output problem?
Probably not - in the short term.
but the cables I used are good, I'm sure.
Never make assumptions - test them.
It has no output.
What does it normally do? Does it require any setup or adjustment to get an output?
 

kellys_eye

Jun 25, 2010
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That device operates using an interface card fitted in a PC. It will do 'nothing' just powered up and standing there. Have you connected it to the appropriate interface and used the correct controlling software?
 

roughshawd

Jul 13, 2020
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Simple midi module... In- out-thru... With a stereo out put with phone cables...
U
I'm on a stupid phone can't read the numbers they're upside down can you just write them thank you
7739 sumthin... Wrong button=missing image. Will get back to you on that...
 

Martaine2005

May 12, 2015
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What are you using for input?.
‘Thru’ is just a direct connection from front to back.
 

roughshawd

Jul 13, 2020
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I tested the cables, and I am using an Ensoniq SD-1 for midi triggering.

First, I connected the midi cables to different ports, thinking maybe there was an in out thru bug... But no good.

So I was thinking what might just stop the output. It's all digital, so I thought about maybe a diode loop.

With the power and cables disconnected, I started looking for residual power on the board, sometimes caps lock a few millivolts in a latching loop that stops micro-switching. There was between .007 and .001 volts stored in the caps of the output section of the board.

As I looked for a drain, all the IC's in the output,... there are 4 of them.... Had residual voltage above .003v with the unit unplugged and the power off.

So now I have to get over the "shelf it" shakes, and test it...

Tell me, is there anyone here who trusts themselves???!!!!?!?!!
 

roughshawd

Jul 13, 2020
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Test failed. Found bronen plastic mounting bracket on control board mounting, but that should not affect the operation of the device. I can't find any bad resistors, and it seems to be in working order. Duh. Duh duh duh, duh woohoo.. duh. Duh...
 

roughshawd

Jul 13, 2020
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Put project away for Christmas. I will try not to drown my sorrows in multiple types of alcoholic libations, and rum soaked candies and cakes. Please be careful on the ice this winter, and watch out for those Christmas Shoppers who can't see Santa for the snow.... Merry Christmas, Happy New Year. I have found when you are not sure of what you are doing, that just minding your own business usually is inconsequential. May the angels dance and sing, those little cherubuks not shoot arrows in the cockatoo, and your tippy glass always stay upright!!! What's that smell...oh I'm on fire!!!!
 

Delta Prime

Jul 29, 2020
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My homemade crystal radio had a diode loop antenna coil...
Sorry that's as close as I can get.
Even back then I had an old fashioned fire extinguisher at the ready. 1703190897287.jpg
 

Bluejets

Oct 5, 2014
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Still no response from the suggestion that you probably connect it arse about with the dodgy power supply (negative to tip)
 
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