HOLY SMOKES! It's a small world inside these black boxes! Yes, I do have your
(ex)TX802 S/N:TMO1877

I'm impressed (not that easy) and grateful (rare) for all the work you put into
this. As I am cheap and LAZY, I will just either switch it on or off until I
get carpal tunnel, or just leave it on all the time. I will provide the 4MHz
signal when the carpal tunnel or electric bill forces the issue.

The fellow that sold it gave a full disclosure of the problem in the ebay ad.

As far as the prom, lazy will probably win out over cheap (depending on
shipping) as Loscha has everything needed.

It looks more and more like I ought to get a couple ATMega/arduino type things
around here just in case.

Thanks a mil, Alan. It is a comfort to know that there are still people
competent INSIDE the box.

l8r,
Nick






--- In yamahablackboxes@yahoogroups.com, Alan Probandt <alan_probandt@...>
wrote:
>
> Hello,
>
>   I believe that I'm a previous owner of this TX802.  I don't have the serial
number, but I think that it was 1877.   I recently sold a TX802 that had the
same condition and the person that I sold it to recently resold it about two
weeks ago on eBay.
>
>   I toyed with fixing the power-on issue.  With an oscilloscope, I noticed
that the CL1 (4MHz ceramic resonator) on the Master CPU had no 4MHz square wave
when power cycling the switch would not turn on the unit.  When the unit turned
on right after pressing the power switch, there was always a 4MHz clock signal
on the EXTAL (pin 3 of IC1 Master CPU).  Possibly replacing this 4MHz ceramic
resonator and the two 22pF capacitors would fix it.  Or making an external 4MHz
clock source, such as a 4MHz crystal with a 74HC14 inverter used as a
oscillator, or the clock out of an inexpensive 8MHz AVR CPU divided by a
flip-flop. Then connect this external 4MHz square wave to the EXTAL pin 3 of the
Master CPU.
>
>   A 32K EPROM such an old 27C256 should work, as might a 32K EEPROM for the OS
upgrade.  An EEPROM if one could be found for cheap that fit into the original
pinout, would be better because it is much easier to make an EEPROM programmer
than a EPROM dev system (which needs an ultra-violet eraser as well as a device
programmer).
>
>  I used to get a lot of 1Mbit (128K bytes) EEPROMs from discarded very old PC
motherboards.  They held the BIOS code and were in sockets.  I built a EEPROM
reprogrammer from an AVR Mega162 microcontroller.   This might be a cheap
alternative to a ExPROM development system.    The pins of a 1Mbit EEPROM are
the same as a 27C256 in the region between pins 3 and 30.  A 1Mbit EEPROM would
fit into the socket of a 27C256 but there would have to be a wire jump betweens
pins 30 and 32.  I'll try this if I needed a 27C256 and only had a 1Mbit
EEPROM.  But I'm cheap and crazy.
>
> Alan Probandt
> Portland, OR USA
> alan_probandt@...
>
>
>
> --- On Fri, 6/26/09, Nick Terlesky <Nickster777@...> wrote:
>
> From: Nick Terlesky <Nickster777@...>
> Subject: [yamahablackboxes] Need newer rom version for tx802
> To: yamahablackboxes@yahoogroups.com
> Date: Friday, June 26, 2009, 10:43 PM
>
>
>
>
>
>
>
>
>
>
>
>
> Hi, all.
>  
> I just got a TX802 on ebay that has the original
> rom in it.  It will not accept performances 33 through 64 from my G10c (the
> Yamaha synth-guitar controller unit)... this was a known issue with the v1.0
> firmware.
>  
> I don't own a Prom burner, so my 1st choice (best
> hope) is that someone out there has a v1.5 or v1.6 burned onto a chip which
they
> could sell.
>  
> Failing that,  If anyone has (or can point me
> to)  the latest firmware image, I guess I could buy or build a
> burner.
>  
> Thanks in advance.
> Nick.
>  
> p.s. Also,this particular unit (tx802),if left
> turned off for more than a day, doesn't want to bootup until 6-12 tries.  I
> just get black block across the width of the 1st line of the display.  Any
> info on this would be welcome, indeed.
>