Hello,
   Welcome to select group of people that have discovered plugging an FB01 into a
stompbox chain!
   All the stompboxes accept line level (between 0.5 and 1.5 volts peak-to-peak)
signals as inputs.  The FB01 puts out a signal in this range. If you are playing
all eight FB01 voices at the same time, then the signal will go above this range
and the signals that are output from the stompbox will distort.  But you are not
going to 'fry' anything.
   The inputs of the stompboxes have either a op-amp first stage or a transistor
input buffer.  These all generally have a 4.7K ohm to 10K ohm resistor before
the op-amp input or the transistor base.  This will protect the stompbox input
from large input voltages and currents.  If the FB01 causes distortion, turn
down the volume of the FB01 voices.  They are set to 127 by default.  Set them
to 100 or 85.  The FB01 has capacitors on its audio outputs so that no DC offset
voltage will go to the stompboxes.

   If you can do MIDI programming then try having every second note go to a
second MIDI channel.  Then have the pitch bend on the FB01 affect only the
channel of the second note.  This allows the FB01 to emulate the effect of
playing notes on two strings of the guitar while bending only one string.

  The voices of the FB01 are programmable but not to the extent that they are on
the TX81Z or TG77.  Custom scales can be set up, but this requires sending a
sysex message (about 6-8 bytes) for each note instead of the normal three byte
note-on message.

There is a manual at
http://www2.yamaha.co.jp/manual/pdf/emi/english/synth/DX7E1.pdf which
appears to include programming instructions. I hope that helps you out.

ALAN

----- Original Message -----
From: "wendyorwalter" <mailbox@...>
To: <yamahablackboxes@yahoogroups.com>
Sent: Friday, November 27, 2009 1:16 PM
Subject: [yamahablackboxes] manual for dx7


> this manual at
> http://www.maths.abdn.ac.uk/~bensondj/dx7/manuals/dx7-man.pdf
>
> appears to have a few essential pages missing: I definitely need actual
> page 27 (pdf page 32). It's blank and I need it to get started with
> programming...does anyone have a complete manual or even just that page?
>
> I've searched/googled etc without any luck so any help would be much
> appreciated.

this manual at http://www.maths.abdn.ac.uk/~bensondj/dx7/manuals/dx7-man.pdf

appears to have a few essential pages missing: I definitely need actual page 27
(pdf page 32). It's blank and I need it to get started with programming...does
anyone have a complete manual or even just that page?

I've searched/googled etc without any luck so any help would be much
appreciated.

Hey all,

This is my first post to the group.  Shortly after I acquired my FB01(I got a
killer price on it at a local public radio station sale...free, with the
purchase of some records), I set it up to see if it even worked(that's why I got
it for free, they didn't even know if it worked).  To my surprise, it did.  The
signal path I used for the test was my MIDI controller, into a Line 6 M13
stompbox modeler, then to my little 5 watt amp.  it worked, and some of the
processing stuff I did took this black box from ordinary, to way cool(on an
organ tone, with a tube compressor, rotary speaker and some nice hall reverb). 
Now, not to stray too far off the subject, since buying the M13, I now have a
lot of unused stompboxes laying around.  My idea was to press them back into use
with the FB01, using a Big Muff, a DOD Vibro Thang, a Phaser, a Rotary
simulator,a Delay, and finally into a looper pedal.  The only box I am not
concerned about is the Rotary sim, because it has a keyboard switch to
accommodate for line levels, but will it hurt the other effects?  If it might,
is there a way to convert the signal so the pedals will not fry?

Thanks,

Bri

I get alot of the switches I need for these older keyboards from Mouser.com. In
both their catalogs and online they have pictures and measurements of the
switches. They also have a 30 day return policy so if it doesnt fit and you
havent tried to solder it in you can return them for a full refund.

--- In yamahablackboxes@yahoogroups.com, "GB" <grantbt@...> wrote:
>
> > SeedStudio.com also has some *very* cheap ones ($.10ea) , but they are in
> > China.
>
> Correction: http://www.seeedstudio.com/depot/
>
>
>
> GB
>

> SeedStudio.com also has some *very* cheap ones ($.10ea) , but they are in
> China.

Correction: http://www.seeedstudio.com/depot/



GB

Hi Grant,

For the 4 leg switches I used Jameco 153251. There are data sheets available so
you can check them for fit. I must have put over a hundred of these into my
Peavey DPM gear over the years. I still have a bunch here...

For the 2 leg Roland style switches I used Digikey EG4378CT-ND. These were used
in all the "D" series gear.

Cheers, Fran

--- In yamahablackboxes@yahoogroups.com, "GB" <grantbt@...> wrote:
>
> I'm on the last few items of a major DX27 restoration.  I have a couple of
> panel switches that don't work and I don't know where to get replacements
> (in the USA).  They are small SPST momentary switches and the body is about
> 5 or 6mm per side. It looks like this ( http://tinyurl.com/ybeq3j2 ) except
> through-hole.  The DX27 manual appears to call them "evq-qsl04M" but they
> must be the same as on some of the other DX synths. I'd try DigiKey except
> you can't browse by image.  Any ideas?
>
> GB
>

Jason, Awesome info page! You've been helping me with manuals and info for a
while now. Like the Ensoniq VFX-SD... Thank you and please keep up the great
work. Fran

--- In yamahablackboxes@yahoogroups.com, "xangis" <xangis@...> wrote:
>
> Howdy YBBers,
>
> Over the past year or so I've been trying to build a public archive of
datasheets and info for synth and soundcard-related sound chips.  What I have so
far is here:
>
> http://soundprogramming.net/electronics_reference/sound_chips
>
> If anyone has a datasheet or other info I don't have I'd be happy to post it.
>
> Thanks,
> Jason
>

I'm on the last few items of a major DX27 restoration.  I have a couple of
panel switches that don't work and I don't know where to get replacements
(in the USA).  They are small SPST momentary switches and the body is about
5 or 6mm per side. It looks like this ( http://tinyurl.com/ybeq3j2 ) except
through-hole.  The DX27 manual appears to call them "evq-qsl04M" but they
must be the same as on some of the other DX synths. I'd try DigiKey except
you can't browse by image.  Any ideas?

GB

Howdy YBBers,

Over the past year or so I've been trying to build a public archive of
datasheets and info for synth and soundcard-related sound chips.  What I have so
far is here:

http://soundprogramming.net/electronics_reference/sound_chips

If anyone has a datasheet or other info I don't have I'd be happy to post it.

Thanks,
Jason

SOLVED! Thanks a lot, I changed both of the 1000uf caps for good measure, I had
a few laying around, and they're better quality too, rated a bit higher in the
voltage. This solved my distortion problem. Anyway, I'd like to thank all of you
guys for your helpful input and great patience with me! It's always awesome to
fix something yourself, and I couldn't have done it without this forum!

Thanks again!

--- In yamahablackboxes@yahoogroups.com, Alan Probandt <alan_probandt@...>
wrote:
>
> Hello,
>   Do you have an oscilloscope?  If not then try downloading one of the
programs that use the PC sound card as a scope.  These programs sample at 44,100
samples per second, which is really slow for a scope but functional for simple
tests.   Since they use the audio line input, the max voltage has to be only
about 1 volt peak-to-peak.  So you need to use some resistors to reduce the
signal to that max level.  And the input signal has to be AC because the sound
card has capacitors on the audio line inputs.
>   I would assume that one of the capacitors for either the plus 15 volts or
the minus 15 volts has dried out on the power supply board and this is causing
ripple voltage from the power supply to feed into the TX81Z audio output
op-amps.
>
>   The power supply shows six caps on the +/- 15v section.  Two big 1000uF
ones, two small 22uF cans (after the regulators), and two 0.1uF ones.  The
1000uF ones are  probably bad.  If the 1000uF caps were bad, then the full half
sine wave would be fed into the voltage regulator.  Some of that signal would go
through the regulator.  Again check the voltage for +5 and +/- 15v. 
Unfortunately a voltmeter won't show if there is ripple voltage because the
ripple frequency is 120 Hz (twice the mains 60Hz frequency).  These caps don't
last more than 2-3 thousand hours of use. They cost about a  US dollar each
(possibly about 1 pound each in the UK).  Be sure to be aware of where the high
mains voltage parts and traces are located on the power supply board so you
don't get a shock.
>
>  
>
> __________________________________________________
> Do You Yahoo!?
> Tired of spam?  Yahoo! Mail has the best spam protection around
> http://mail.yahoo.com
>

----- Original Message -----

From: Mark

To: yamahablackboxes@yahoogroups.com

Sent: Sunday, November 15, 2009 6:17 PM

Subject: [yamahablackboxes] Re: TX81Z with distorted output - please help!

 

NEW DEVELOPMENT!

I started to think outside the synth board itself and immediately disassembled my other working TX81Z. I stuck the working synth board in the distorted TX81Z's shell and voila, SAME distortion. This is HUGE, now we are dealing with something totally different.

This leads me to believe that the POWER SUPPLY BOARD is at fault. What should I check, without killing myself? Could there be too much leakage going to the main board?

--- In yamahablackboxes@yahoogroups.com, "jammie" <jammie.emma@...> wrote:
>
> check polarity between the tracks of the ic10 and the dac as you stated that the old opamp worked but the new one didnot it might be a damaged or craked pcb track or it might be you soldering on the new ic sockets or a cold solder joint on the power pins make sure you are getting voltage to the opamp of ic10 which is betwwen 12 and 15vdc for the + and - voltages
> ----- Original Message -----
> From: Mark
> To: yamahablackboxes@yahoogroups.com
> Sent: Sunday, November 15, 2009 6:36 AM
> Subject: [yamahablackboxes] Re: TX81Z with distorted output - please help!
>
>
>
> Well, I'm about to give up. I stuck the new DAC in the TX81Z and... nothing. No change in the sound. Still that annoying static burst. I'm going to change that 0.1 uf cap and see what happens, I have a ton of those.
>
> I'm going to pull my hair out with this thing.
>
> --- In yamahablackboxes@yahoogroups.com, Alan Probandt <alan_probandt@> wrote:
> >
> > It is bizarre that the old IC works but a replacement doesn't for IC10. It doesn't make sense. Maybe there is a hairline break in the solder for the pins on the DAC chip. Try resoldering all the joints where the DAC pins meet the main circuit board.
> >
> > I would believe that the two dual op-amps that come after the DAC filter the stairsteps. The first dual op-amp (IC2) is a non-inverting buffer and the second (IC1) is a third-order low-pass filter.
> >
> > I also guess that TR1 and TR2 act to mute the sound output when the power is turned on. They prevent a burst of noise coming through the speakers when the TX81Z is powered up. This is just an assumption on my part. I can't imagine what else that they would be there for.
> >
> > The 0.1uF cap on the DAC would be to reduce any spikes in the power supply from entering the audio or affecting the operation of the DAC. It is called a bypass capacitor. I assume that it is the one on the schematic that is between +5 volts (pin 1) and ground (pins 3,8, and 16).
> >
>
>
>
>
>
>
> ----------------------------------------------------------
>
>
>
> No virus found in this incoming message.
> Checked by AVG - www.avg.com
> Version: 8.5.425 / Virus Database: 270.14.65/2502 - Release Date: 11/14/09 07:43:00
>

---

No virus found in this incoming message.
Checked by AVG - www.avg.com
Version: 8.5.425 / Virus Database: 270.14.65/2502 - Release Date: 11/14/09 07:43:00

NEW DEVELOPMENT!

I started to think outside the synth board itself and immediately disassembled
my other working TX81Z. I stuck the working synth board in the distorted TX81Z's
shell and voila, SAME distortion. This is HUGE, now we are dealing with
something totally different.

This leads me to believe that the POWER SUPPLY BOARD is at fault. What should I
check, without killing myself? Could there be too much leakage going to the main
board?

--- In yamahablackboxes@yahoogroups.com, "jammie" <jammie.emma@...> wrote:
>
> check polarity between the tracks of the ic10 and the dac as you stated that
the old opamp worked but the new one didnot it might be a damaged or craked pcb
track or it might be you soldering on the new ic sockets or a cold solder joint
on the power pins make sure you are getting voltage to the opamp of ic10  which
is betwwen 12 and 15vdc for the + and - voltages
>   ----- Original Message -----
>   From: Mark
>   To: yamahablackboxes@yahoogroups.com
>   Sent: Sunday, November 15, 2009 6:36 AM
>   Subject: [yamahablackboxes] Re: TX81Z with distorted output - please help!
>
>
>
>   Well, I'm about to give up. I stuck the new DAC in the TX81Z and... nothing.
No change in the sound. Still that annoying static burst. I'm going to change
that 0.1 uf cap and see what happens, I have a ton of those.
>
>   I'm going to pull my hair out with this thing.
>
>   --- In yamahablackboxes@yahoogroups.com, Alan Probandt <alan_probandt@>
wrote:
>   >
>   > It is bizarre that the old IC works but a replacement doesn't for IC10. It
doesn't make sense.  Maybe there is a hairline break in the solder for the pins
on the DAC chip.  Try resoldering all the joints where the DAC pins meet the
main circuit board.
>   >
>   >   I would believe that the two dual op-amps that come after the DAC filter
the stairsteps.  The first dual op-amp (IC2) is a non-inverting buffer and the
second (IC1) is a third-order low-pass filter.
>   >
>   >   I also guess that TR1 and TR2 act to mute the sound output when the
power is turned on.  They prevent a burst of noise coming through the speakers
when the TX81Z is powered up.  This is just an assumption on my part.  I can't
imagine what else that they would be there for.
>   >
>   >   The 0.1uF cap on the DAC would be to reduce any spikes in the power
supply from entering the audio or affecting the operation of the DAC.  It is
called a bypass capacitor.  I assume that it is the one on the schematic that is
between +5 volts (pin 1)  and ground (pins 3,8, and 16).
>   >
>
>
>
>
>
>
> ------------------------------------------------------------------------------
>
>
>
>   No virus found in this incoming message.
>   Checked by AVG - www.avg.com
>   Version: 8.5.425 / Virus Database: 270.14.65/2502 - Release Date: 11/14/09
07:43:00
>

----- Original Message -----

From: Mark

To: yamahablackboxes@yahoogroups.com

Sent: Sunday, November 15, 2009 6:36 AM

Subject: [yamahablackboxes] Re: TX81Z with distorted output - please help!

 

Well, I'm about to give up. I stuck the new DAC in the TX81Z and... nothing. No change in the sound. Still that annoying static burst. I'm going to change that 0.1 uf cap and see what happens, I have a ton of those.

I'm going to pull my hair out with this thing.

--- In yamahablackboxes@yahoogroups.com, Alan Probandt <alan_probandt@...> wrote:
>
> It is bizarre that the old IC works but a replacement doesn't for IC10. It doesn't make sense.  Maybe there is a hairline break in the solder for the pins on the DAC chip.  Try resoldering all the joints where the DAC pins meet the main circuit board.
>
>   I would believe that the two dual op-amps that come after the DAC filter the stairsteps.  The first dual op-amp (IC2) is a non-inverting buffer and the second (IC1) is a third-order low-pass filter.
>
>   I also guess that TR1 and TR2 act to mute the sound output when the power is turned on.  They prevent a burst of noise coming through the speakers when the TX81Z is powered up.  This is just an assumption on my part.  I can't imagine what else that they would be there for.
>
>   The 0.1uF cap on the DAC would be to reduce any spikes in the power supply from entering the audio or affecting the operation of the DAC.  It is called a bypass capacitor.  I assume that it is the one on the schematic that is between +5 volts (pin 1)  and ground (pins 3,8, and 16).
>

---

No virus found in this incoming message.
Checked by AVG - www.avg.com
Version: 8.5.425 / Virus Database: 270.14.65/2502 - Release Date: 11/14/09 07:43:00

Have you tried a reset from the internal test program? How about shutting off
the FX setting? Failing that I would blame a dropped bit in the ops chip.

--- In yamahablackboxes@yahoogroups.com, "Mark" <casiotone1331@...> wrote:
>
> Well, I'm about to give up. I stuck the new DAC in the TX81Z and... nothing.
No change in the sound. Still that annoying static burst. I'm going to change
that 0.1 uf cap and see what happens, I have a ton of those.
>
> I'm going to pull my hair out with this thing.
>
> --- In yamahablackboxes@yahoogroups.com, Alan Probandt <alan_probandt@> wrote:
> >
> > It is bizarre that the old IC works but a replacement doesn't for IC10. It
doesn't make sense.  Maybe there is a hairline break in the solder for the pins
on the DAC chip.  Try resoldering all the joints where the DAC pins meet the
main circuit board.
> >
> >   I would believe that the two dual op-amps that come after the DAC filter
the stairsteps.  The first dual op-amp (IC2) is a non-inverting buffer and the
second (IC1) is a third-order low-pass filter.
> >
> >   I also guess that TR1 and TR2 act to mute the sound output when the power
is turned on.  They prevent a burst of noise coming through the speakers when
the TX81Z is powered up.  This is just an assumption on my part.  I can't
imagine what else that they would be there for.
> >
> >   The 0.1uF cap on the DAC would be to reduce any spikes in the power supply
from entering the audio or affecting the operation of the DAC.  It is called a
bypass capacitor.  I assume that it is the one on the schematic that is between
+5 volts (pin 1)  and ground (pins 3,8, and 16).
> >
>

Well, I'm about to give up. I stuck the new DAC in the TX81Z and... nothing. No
change in the sound. Still that annoying static burst. I'm going to change that
0.1 uf cap and see what happens, I have a ton of those.

I'm going to pull my hair out with this thing.

--- In yamahablackboxes@yahoogroups.com, Alan Probandt <alan_probandt@...>
wrote:
>
> It is bizarre that the old IC works but a replacement doesn't for IC10. It
doesn't make sense.  Maybe there is a hairline break in the solder for the pins
on the DAC chip.  Try resoldering all the joints where the DAC pins meet the
main circuit board.
>
>   I would believe that the two dual op-amps that come after the DAC filter the
stairsteps.  The first dual op-amp (IC2) is a non-inverting buffer and the
second (IC1) is a third-order low-pass filter.
>
>   I also guess that TR1 and TR2 act to mute the sound output when the power is
turned on.  They prevent a burst of noise coming through the speakers when the
TX81Z is powered up.  This is just an assumption on my part.  I can't imagine
what else that they would be there for.
>
>   The 0.1uF cap on the DAC would be to reduce any spikes in the power supply
from entering the audio or affecting the operation of the DAC.  It is called a
bypass capacitor.  I assume that it is the one on the schematic that is between
+5 volts (pin 1)  and ground (pins 3,8, and 16).
>

It is bizarre that the old IC works but a replacement doesn't for IC10. It
doesn't make sense.  Maybe there is a hairline break in the solder for the pins
on the DAC chip.  Try resoldering all the joints where the DAC pins meet the
main circuit board.

  I would believe that the two dual op-amps that come after the DAC filter the
stairsteps.  The first dual op-amp (IC2) is a non-inverting buffer and the
second (IC1) is a third-order low-pass filter.

  I also guess that TR1 and TR2 act to mute the sound output when the power is
turned on.  They prevent a burst of noise coming through the speakers when the
TX81Z is powered up.  This is just an assumption on my part.  I can't imagine
what else that they would be there for.

  The 0.1uF cap on the DAC would be to reduce any spikes in the power supply
from entering the audio or affecting the operation of the DAC.  It is called a
bypass capacitor.  I assume that it is the one on the schematic that is between
+5 volts (pin 1)  and ground (pins 3,8, and 16).

Duh! I just read the manual. It does blink on low battery power.

--- In yamahablackboxes@yahoogroups.com, "narfman96" <narfman96@...> wrote:
>
> It's really weird how the LED is switched through a transistor from a CPU
line??? My take on what it shows is that the power is on. Every DX100 pic I look
on the web shows it's on if it's powered up. Maybe so you won't forget to power
off when using batteries. Or maybe it blinks if battery power is losing it to
warn of impending doom. You won't have to worry about that with the DX27...
>
> --- In yamahablackboxes@yahoogroups.com, "GB" <grantbt@> wrote:
> >
> > Thanks for checking.  I think I might hook up the LED that the DX100 had.
Not sure what it does though.  I had to put in a (the) contrast pot for the new
LCD.
> >
> >   ----- Original Message -----
> >   From: narfman96
> >   To: yamahablackboxes@yahoogroups.com
> >   Sent: Friday, November 13, 2009 5:55 AM
> >   Subject: [yamahablackboxes] Re: DX27 DX100 v1.2 EPROM image
> >
> >
> >
> >   Hi Grant,
> >
> >   I fired up my DX27 today after finally finding the Service Manual.
Pressing buttons 1 and 2 on power up shows Version 1.1 02-AUG-85. So I can't
help with the V1.2 image. Plus the mask rom (IC11) is soldered to the board. Let
me know if you find a copy though... Now to check out the 24 4 op voices in this
thing that I haven't heard in a while.
> >
> >   Fran
> >   --- In yamahablackboxes@yahoogroups.com, "grantpbt" <grantbt@> wrote:
> >   >
> >   > Hi,
> >   >
> >   > (I also posted this in YamahaDX)
> >   > Does anyone have an EPROM image for v1.2 of the DX27 "OS"? I'm doing a
refurb and would like to upgrade it while it's open.
> >   >
> >   > Thx
> >   > GB
> >   > www.musictechnologiesgroup.com
> >   >
> >
>

It's really weird how the LED is switched through a transistor from a CPU
line??? My take on what it shows is that the power is on. Every DX100 pic I look
on the web shows it's on if it's powered up. Maybe so you won't forget to power
off when using batteries. Or maybe it blinks if battery power is losing it to
warn of impending doom. You won't have to worry about that with the DX27...

--- In yamahablackboxes@yahoogroups.com, "GB" <grantbt@...> wrote:
>
> Thanks for checking.  I think I might hook up the LED that the DX100 had. Not
sure what it does though.  I had to put in a (the) contrast pot for the new LCD.
>
>   ----- Original Message -----
>   From: narfman96
>   To: yamahablackboxes@yahoogroups.com
>   Sent: Friday, November 13, 2009 5:55 AM
>   Subject: [yamahablackboxes] Re: DX27 DX100 v1.2 EPROM image
>
>
>
>   Hi Grant,
>
>   I fired up my DX27 today after finally finding the Service Manual. Pressing
buttons 1 and 2 on power up shows Version 1.1 02-AUG-85. So I can't help with
the V1.2 image. Plus the mask rom (IC11) is soldered to the board. Let me know
if you find a copy though... Now to check out the 24 4 op voices in this thing
that I haven't heard in a while.
>
>   Fran
>   --- In yamahablackboxes@yahoogroups.com, "grantpbt" <grantbt@> wrote:
>   >
>   > Hi,
>   >
>   > (I also posted this in YamahaDX)
>   > Does anyone have an EPROM image for v1.2 of the DX27 "OS"? I'm doing a
refurb and would like to upgrade it while it's open.
>   >
>   > Thx
>   > GB
>   > www.musictechnologiesgroup.com
>   >
>

----- Original Message -----

From: narfman96

To: yamahablackboxes@yahoogroups.com

Sent: Friday, November 13, 2009 5:55 AM

Subject: [yamahablackboxes] Re: DX27 DX100 v1.2 EPROM image

 

Hi Grant,

I fired up my DX27 today after finally finding the Service Manual. Pressing buttons 1 and 2 on power up shows Version 1.1 02-AUG-85. So I can't help with the V1.2 image. Plus the mask rom (IC11) is soldered to the board. Let me know if you find a copy though... Now to check out the 24 4 op voices in this thing that I haven't heard in a while.

Fran
--- In yamahablackboxes@yahoogroups.com, "grantpbt" <grantbt@...> wrote:
>
> Hi,
>
> (I also posted this in YamahaDX)
> Does anyone have an EPROM image for v1.2 of the DX27 "OS"? I'm doing a refurb and would like to upgrade it while it's open.
>
> Thx
> GB
> www.musictechnologiesgroup.com
>

Hi Grant,

I fired up my DX27 today after finally finding the Service Manual. Pressing
buttons 1 and 2 on power up shows Version 1.1 02-AUG-85. So I can't help with
the V1.2 image. Plus the mask rom (IC11) is soldered to the board. Let me know
if you find a copy though... Now to check out the 24 4 op voices in this thing
that I haven't heard in a while.

Fran
--- In yamahablackboxes@yahoogroups.com, "grantpbt" <grantbt@...> wrote:
>
> Hi,
>
> (I also posted this in YamahaDX)
> Does anyone have an EPROM image for v1.2 of the DX27 "OS"?  I'm doing a refurb
and would like to upgrade it while it's open.
>
> Thx
> GB
> www.musictechnologiesgroup.com
>

Hi,

(I also posted this in YamahaDX)
Does anyone have an EPROM image for v1.2 of the DX27 "OS"?  I'm doing a refurb
and would like to upgrade it while it's open.

Thx
GB
www.musictechnologiesgroup.com

----- Original Message -----

From: jammie

To: yamahablackboxes@yahoogroups.com

Sent: Wednesday, November 11, 2009 12:46 PM

Subject: Re: [yamahablackboxes] Re: TX81Z with distorted output - please help!

 

did you check the voltage on the chip incommer it should be between 7-17 vdc

 

it does look like its the dac the second sound channel buffering opamp is not functioning

 

there are no caps for the dac as the sample and hold circuits are from the fm chip it switches the analog switch which inturns sends the voltage to the buffering opamp which smooths it

 

very unusual chip design

 

its usually the dac sends the step voltage to a sample and hold ic which is then fed to a buffering opamp  which smoothes it then theres the filter then theres the line level opamp for the out put thats how most

 

digital and analog hybrids are done

 

check the opamp signal should be 5-7 volts

 

also do polarity on your solder joint to the chip in question test from the pin comming from the dac top side and the ic socket and see if you get polarity on each connection 

----- Original Message -----

From: Mark

To: yamahablackboxes@yahoogroups.com

Sent: Wednesday, November 11, 2009 4:46 AM

Subject: [yamahablackboxes] Re: TX81Z with distorted output - please help!

 

OK, I changed most of the opamps but the sound is still there. I installed sockets to avoid the headaches of desoldering, so I've been chip swapping all night.

All of the replacement ICs work fine, but IC10, the opamp right next to the DAC wont produce a peep unless the original chip is in. Now IC2 is the same chip, NJM072D. I bought 2 of these from Mouser. The replacement works in IC2's socket, but when placed in IC10's socket, there is nothing but silence, unless you bang on the keyboard, which then you get a burst of static. So right now I have NJM4558, NJM4556, and one NJM072D seated and working fine. The socket after the DAC is back to the old chip, and still producing noise. I think I'm going to get that DAC and give it a shot, what do you guys think? Is there any reason that the new opamp doesn't work if it works in the other 072D socket?

Also, where are the caps located to smooth the DAC? Is it the 104M ceramic disc at the bottom of the chip?

--- In yamahablackboxes@yahoogroups.com, "jammie" <jammie.emma@...> wrote:
>
> im a synth tech and fix many machines at component level i was a ensoniq repair tech and yam and akai and all things wonderfully analog
>
> i also make upgrades with other parties to keep these machines alive
> ----- Original Message -----
> From: narfman96
> To: yamahablackboxes@yahoogroups.com
> Sent: Wednesday, November 04, 2009 2:42 PM
> Subject: [yamahablackboxes] Re: TX81Z with distorted output - please help!
>
>
> Jammie, You just blew me away on that one!!! What else have you got laying around in your bag of tricks? Awesome....
> Thank you for posting the datasheet and passing along a parts source.
> You're the man, Fran
>
> --- In yamahablackboxes@yahoogroups.com, "jammie" <jammie.emma@> wrote:
> >
> > my bad looking at the wrong schematic ym3012 is a yamaha part and was used in many games machines ill post this dac to the files section you can get them for $8
> >
> > you can get them from arcade chips in usa
>
>
>
>
>
>
> ----------------------------------------------------------
>
>
>
> No virus found in this incoming message.
> Checked by AVG - www.avg.com
> Version: 8.5.424 / Virus Database: 270.14.48/2479 - Release Date: 11/03/09 19:38:00
>

---

No virus found in this incoming message.
Checked by AVG - www.avg.com
Version: 8.5.425 / Virus Database: 270.14.59/2494 - Release Date: 11/10/09 07:38:00

---

No virus found in this incoming message.
Checked by AVG - www.avg.com
Version: 8.5.425 / Virus Database: 270.14.60/2495 - Release Date: 11/10/09 19:56:00

----- Original Message -----

From: Mark

To: yamahablackboxes@yahoogroups.com

Sent: Wednesday, November 11, 2009 4:46 AM

Subject: [yamahablackboxes] Re: TX81Z with distorted output - please help!

 

OK, I changed most of the opamps but the sound is still there. I installed sockets to avoid the headaches of desoldering, so I've been chip swapping all night.

All of the replacement ICs work fine, but IC10, the opamp right next to the DAC wont produce a peep unless the original chip is in. Now IC2 is the same chip, NJM072D. I bought 2 of these from Mouser. The replacement works in IC2's socket, but when placed in IC10's socket, there is nothing but silence, unless you bang on the keyboard, which then you get a burst of static. So right now I have NJM4558, NJM4556, and one NJM072D seated and working fine. The socket after the DAC is back to the old chip, and still producing noise. I think I'm going to get that DAC and give it a shot, what do you guys think? Is there any reason that the new opamp doesn't work if it works in the other 072D socket?

Also, where are the caps located to smooth the DAC? Is it the 104M ceramic disc at the bottom of the chip?

--- In yamahablackboxes@yahoogroups.com, "jammie" <jammie.emma@...> wrote:
>
> im a synth tech and fix many machines at component level i was a ensoniq repair tech and yam and akai and all things wonderfully analog
>
> i also make upgrades with other parties to keep these machines alive
> ----- Original Message -----
> From: narfman96
> To: yamahablackboxes@yahoogroups.com
> Sent: Wednesday, November 04, 2009 2:42 PM
> Subject: [yamahablackboxes] Re: TX81Z with distorted output - please help!
>
>
> Jammie, You just blew me away on that one!!! What else have you got laying around in your bag of tricks? Awesome....
> Thank you for posting the datasheet and passing along a parts source.
> You're the man, Fran
>
> --- In yamahablackboxes@yahoogroups.com, "jammie" <jammie.emma@> wrote:
> >
> > my bad looking at the wrong schematic ym3012 is a yamaha part and was used in many games machines ill post this dac to the files section you can get them for $8
> >
> > you can get them from arcade chips in usa
>
>
>
>
>
>
> ----------------------------------------------------------
>
>
>
> No virus found in this incoming message.
> Checked by AVG - www.avg.com
> Version: 8.5.424 / Virus Database: 270.14.48/2479 - Release Date: 11/03/09 19:38:00
>

---

No virus found in this incoming message.
Checked by AVG - www.avg.com
Version: 8.5.425 / Virus Database: 270.14.59/2494 - Release Date: 11/10/09 07:38:00

I snagged an YM3012 at Andy's Arcade. It's in the UK , and even with the
shipping to the US I only paid 9 bucks. What a steal!

Hopefully this works.

--- In yamahablackboxes@yahoogroups.com, "jammie" <jammie.emma@...> wrote:
>
> im a synth tech and fix many machines at component level i was a ensoniq
repair tech and yam and akai and all things wonderfully analog
>
> i also make upgrades with other parties to keep these machines alive
>   ----- Original Message -----
>   From: narfman96
>   To: yamahablackboxes@yahoogroups.com
>   Sent: Wednesday, November 04, 2009 2:42 PM
>   Subject: [yamahablackboxes] Re: TX81Z with distorted output - please help!
>
>
>     Jammie, You just blew me away on that one!!! What else have you got laying
around in your bag of tricks? Awesome....
>   Thank you for posting the datasheet and passing along a parts source.
>   You're the man, Fran
>
>   --- In yamahablackboxes@yahoogroups.com, "jammie" <jammie.emma@> wrote:
>   >
>   > my bad looking at the wrong schematic ym3012 is a yamaha part and was used
in many games machines ill post this dac to the files section you can get them
for $8
>   >
>   > you can get them from arcade chips in usa
>
>
>
>
>
>
> ------------------------------------------------------------------------------
>
>
>
>   No virus found in this incoming message.
>   Checked by AVG - www.avg.com
>   Version: 8.5.424 / Virus Database: 270.14.48/2479 - Release Date: 11/03/09
19:38:00
>

OK, I changed most of the opamps but the sound is still there. I installed
sockets to avoid the headaches of desoldering, so I've been chip swapping all
night.

All of the replacement ICs work fine, but IC10, the opamp right next to the DAC
wont produce a peep unless the original chip is in. Now IC2 is the same chip,
NJM072D. I bought 2 of these from Mouser. The replacement works in IC2's socket,
but when placed in IC10's socket, there is nothing but silence, unless you bang
on the keyboard, which then you get a burst of static. So right now I have
NJM4558, NJM4556, and one NJM072D seated and working fine. The socket after the
DAC is back to the old chip, and still producing noise. I think I'm going to get
that DAC and give it a shot, what do you guys think? Is there any reason that
the new opamp doesn't work if it works in the other 072D socket?

Also, where are the caps located to smooth the DAC? Is it the 104M ceramic disc
at the bottom of the chip?

--- In yamahablackboxes@yahoogroups.com, "jammie" <jammie.emma@...> wrote:
>
> im a synth tech and fix many machines at component level i was a ensoniq
repair tech and yam and akai and all things wonderfully analog
>
> i also make upgrades with other parties to keep these machines alive
>   ----- Original Message -----
>   From: narfman96
>   To: yamahablackboxes@yahoogroups.com
>   Sent: Wednesday, November 04, 2009 2:42 PM
>   Subject: [yamahablackboxes] Re: TX81Z with distorted output - please help!
>
>
>     Jammie, You just blew me away on that one!!! What else have you got laying
around in your bag of tricks? Awesome....
>   Thank you for posting the datasheet and passing along a parts source.
>   You're the man, Fran
>
>   --- In yamahablackboxes@yahoogroups.com, "jammie" <jammie.emma@> wrote:
>   >
>   > my bad looking at the wrong schematic ym3012 is a yamaha part and was used
in many games machines ill post this dac to the files section you can get them
for $8
>   >
>   > you can get them from arcade chips in usa
>
>
>
>
>
>
> ------------------------------------------------------------------------------
>
>
>
>   No virus found in this incoming message.
>   Checked by AVG - www.avg.com
>   Version: 8.5.424 / Virus Database: 270.14.48/2479 - Release Date: 11/03/09
19:38:00
>

Hi,

I'm new to the list, having just picked up a TX802.
I updated the ROM to v1.3 found in the files section, but I see there was a v1.5
image posted as an attachment a couple of years back.
Anyone got a copy of it handy ?

Cheers,
Colin f