Xpantastic!

Since the VFD's have a limited life, you may not want to leave them on
all the time.


On Tue, Sep 9, 2008 at 4:17 PM, William Cason <randycason102@...> wrote:
> Hmmm, never thought of that one!
>
> Randy
>
> --- On Tue, 9/9/08, Karl <shire03@...> wrote:
>
> From: Karl <shire03@...>
> Subject: The Status of my Autotune & DAC Tests was Re: [xpantastic] Re: It's
> official- my Xpander is sick
> To: xpantastic@yahoogroups.com
> Date: Tuesday, September 9, 2008, 1:03 AM
>
>
> 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@yahoogro ups.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@yahoogro ups.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.
>>
>
>
>