Xpantastic!

Hello Randy,

Sounds right to me.  I was thinking of the times  I have seen techs
leave the synth plugged in and powered up to avoid dumping the memory.
It takes guts but some guys do it.

Best Regards

Karl
--- In xpantastic@yahoogroups.com, William Cason <randycason102@...>
wrote:
>
> If your xpander is not plugged into anything (e.g. the wall) while
unsoldering the battery, I it shouldn't matter if the iron is grounded
or not because there will be no >circuit to complete!  Just make sure
your xpander's not plugged in, and its chassis isn't touching the same
ground that the iron's grounded to (like the chassis of another
>plugged-in device) and you should be OK.
>
> MHO,
> Randy
>
> --- On Sun, 9/7/08, Tony Cappellini cappy2112@... wrote:
>
> From: Tony Cappellini cappy2112@...
> Subject: Re: The Status of my Autotune & DAC Tests was Re:
[xpantastic] Re: It's official- my Xpander is sick
> To: xpantastic@yahoogroups.com
> Date: Sunday, September 7, 2008, 12:11 PM
>
>
>
>
>
>
> > 6.6 V seems very strange for the memory power supply. The battary
> > might need changing.
> The Service manual reads that this should be 4.4 V with power on, and
> 2.xV with power off.
> With power off, the voltage reading is correct.
>
> I will probably change the battery too, since it's been about 10 years
> after it was changed last.
>
> > If you are re-flowing the + side of this circuit ( M+5V) you better
> > make sure you have an un-grounded soldering Iron. If not
> > the +Mem supply will be shorted to ground and then the MEM will be
> > lost.
>
> I will have the solder tech where I work do all of this for me since
> he does soldering all day long.
> I dont trust myself soldering on pcbs. He has a nice temperature
> controlled iron with many removable tips.
>
> > Hope I caught you in time.
> I havne't heard of an ungrounded soldering iron before, but I assume
> you mean that the iron should not have the ground prong of the
> power cord connected. This is easily done with an adapter.
>
> > I notice in the Xpander schematics D4 exsists twice. One is a diode
> > at the top edge of the board the other is an LED for the LFO. Now I
> The D4 I'm referring to is on the Processor board-not the voice or pot
> board. This is how the service manual refers to it.
>
> > If this is shiny brown, this may be soldering flux. This should
> > always be cleaned off the circuit board.
> > After about 5 - 10 years this will eat the solder and cause problems
>
> It doesn't look like flux too me, and is far enough away from where
> the solder flux would have been when it was soldered.
>
> > Well, I be talkin about U811 the main DAC which feeds the voice
> > board. The MP7614C-4 was mad by EXAR and is obsolete per their web
> > site, and the HS3140C-4 was made by SIPEX and is also obsolete.
>
> I googled for this part, and many hits were found on websites that
> specialize in getting rare parts.
> They want orders of $100 or more.
>
> It might not be a bad idea for us to do a group purchase of these, if
> we could find a supplier who would sell us a small order.
>
> > I suppose with digging you can find this part out there somewhere
> > (repair shop or part house which specializes in obsolete parts but
> > you will pay quite a bit).
>
> I wish there was a cross reference online that would tell you which
> commercial devices also used these components
> It would be much easier looking for an appliance than a chip.
>