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  #1  
Old 09-22-2010, 03:28 PM
xray303 xray303 is offline
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Default Strange problem with MidiSpeak

Hi,

I've received my midispeak kit, solder it and mounted (ROM Mode)into my Speak and Spell. (installed with the Diode)
It was working fine for few days, and suddenly during using it, the screen was showing strange chars.
I reseted the Speak and spell and the screen was still strange. When i use the ON, GO, or any button, the sound is glitched like a bent SaS.
During all test i removed the Midi plug to be sure there is not interference with Midi command.
It is strange because sometime it is working fine and sometimes I get glitched/looped sound only using the keypad.

I did then a few tests (also changed the batteries to be sure) :

When i remove totaly the 6 Bus/Glitch Cable, it work fine.
When i remove only the 3 power pin, i get Glitchy sound
When i remove the Bus/Glitch Pin 6, it works fine.


I checked then the voltage (without the Bus/Glitch pins connected to the SaS):

Across C4 5V OK
Pin 11-16 5V OK
Voltage on Bus/Glitch -5V ? The voltage on Bus/Glitch pin 6 is -3.8V

Checked the negative voltage and and get -6.5 Volts wich it is quite strange.

The prob seems too be comming from the Bus/Glitch pin 6 i Will check the MPSA77 voltage tonight.

Another strange thing, the negative voltage of my SaS is -6.5 V but on few pin of the SaS i got -12V !!

Do you think it is possible to get a Schematics of the MidiSpeak to help me finding what's wrong in mine ? maybe only a little part (the part with bus/Glitches)

Regards,

Nicolas
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  #2  
Old 09-24-2010, 08:31 PM
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John John is offline
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Hi Nicolas,

Hmm--I don't see anything in your post that indicates the source of the problem.

If you leave the "bus/glitch" lines connected, and disconnect only the two "keyboard" lines, do you still get the same problem?

There are no schematics available at this time--sorry.
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  #3  
Old 09-26-2010, 11:46 PM
xray303 xray303 is offline
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Hi,

If i leave the bus glitch connected and remove the 2 keyboard lines, i get the same problem.

The prob is disapearing only if i remove the bus/glitches lines. (especially the nb 6)

Regards,

Nico
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  #4  
Old 09-28-2010, 12:22 AM
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My best guess is that one of the connections is periodically getting short-circuited somewhere. That could explain why the install works fine at times, but then malfunctions at others.
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  #5  
Old 11-18-2010, 05:37 PM
xray303 xray303 is offline
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Hi,

Sorry to come so late again ..

I've removed everything and put new cables in it.
I still have the same probs, but did new tests.

When using midi and using xx times the same note, i get sometimes another sound. but i get sound when using midi.

i also get noise on the screen .. and the S&S is crashing rarely.

Nico
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  #6  
Old 11-20-2010, 03:18 PM
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John John is offline
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Hi Nico,

This is tricky to diagnose. Can you post some detailed photos of the installation?

"Noise" on the screen--if it means that the display doesn't appear as it would during normal S&S operation--indicates some sort of bad connection or other problem with the MIDISpeak installation.

If the noise is juts a brief flash on the screen with MIDI is received, this is expected and not a problem.
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