Well, my opinion is that there is an issue with the power supply.
The 4.92 volt is SUPPOSED to be at 5V. A little variance is ok, and
higher (5.05V) especially in an older unit would feed better as it
went across the board. 4.92 is a bit low. Most chips like 4.95 at
least. And remember the farther you measure across a board, the more
the volts will drop lower. In fact, if you knew the correct pin to
test for on the farthest chip physically across the board from the
power supply, and measure the volt reading on the 5 volt pin, it
wouldn't surprise me if it is actually much lower than the 4.92. This
can cause very strange behaviour in logic systems.
It is possible to attach a PC power supply and test, without making
it "permanent". Not an ATX, but an older AT style power supply.... I
would have to see schematics, but am not sure why there would be a 10
volt, it seems that should be twelve. If the power supply is putting
out 10v on a 12v line, then that would be another issue.
Be aware that power supplies have what are called 'rails'. Each rail
is a separate voltage. So the power supply may have:
1 x 5 Volt rail
2 x 12 volt rail
for an example. One 12Volt rail could be ok, and the other bad, then
the bad side can pull down the power on the good one.
I looked at the power supply in my emax when I first got it. They
used diodes to "crowbar" the voltage regulation circuit. Not an
uncommon practice back then, but not done often now (there are better
ways to do this). What I did on my power supply when I first got the
emax was remove it, and resoldered all the connections to the parts
on the power supply. There were a couple of "cold solders" which are
solders that have small cracks in them (sometimes require a
magnifying glass to see them). They will arc and connect part of the
time, then lose connection momentarily at which point the circuit is
broken and no longer works properly. This could cause the lower power
output as well as the strange behaviour. You can resolder all the
parts on the power supply, then if that doesn't seem to help, get the
PC power supply and hook in place of the original supply to do a test...
Just a couple of thoughts.
But what do I know. Having worked as a repair tech for 17 years on
electronic equipment.... I don't know anything ;-)
Thanks,
Ted
On Apr 26, 2007, at 8:51 PM, RICARDO JUAREZ wrote:
> Yep!,I still need a method for verify the 5v of the
> digital, Why we need to measure VR1?????, and how you
> do that????
> Más Saludos
> Ricardo
>
> --- ted Summers <djtbs1@...> wrote:
>
> > That IC is still available (just google it- someone
> > will sell you a
> > single one- may have to do a bit of email to get it)
> > and one bad IC
> > can cause others ICs to heat up as well....
> >
> > But I would still verify the Power Supply first.....
> >
> > Thx,
> > Ted
> >
> > On Apr 26, 2007, at 6:28 AM, RICARDO JUAREZ wrote:
> >
> > > Hi!:
> > > Here´s what a found: IC 14(NS32008) gets very hot,
> > IC
> > > 14 , 9 and IC 17 gets hot, also when you play the
> > > keyboard there´s is sound, not in scale,
> > additionally
> > > as you play, the menu´s system changes going from
> > > everything to everything
> > (master---traspose---change
> > > patches---select, etc)even performs a sequence on
> > the
> > > diskette and blocks the keyboard....tottally a
> > mess.
> > > When you push a button in the panel the system
> > crash
> > > and no sound and changes, hanging the last
> > > note.....despite all this stuff, the patches
> > sounds
> > > very good. Really there´s some processor not doing
> > > well its job, i don´t think i can find one of
> > these
> > > IC´s nowadays, is there any method for reseting
> > this
> > > devices.
> > > Saludos
> > > ricardo
> > >
> > > --- Wayne Griffin <ingsoc_1979@...> wrote:
> > >
> > > > What are the IC #'s on the chips? What do the
> > chips
> > > > say on them??? Did you also reseat *everything*,
> > > > todos
> > > > on the second board, attached to the
> > motherboard?
> > > > [w]
> > > >
> > > > --- RICARDO JUAREZ <cheju_99@...> wrote:
> > > >
> > > > > Wayne:
> > > > > Could you be more specific about the test of
> > the
> > > > 5V
> > > > > digital power ?, because last night i worked
> > on
> > > > the
> > > > > machine, I check de purple, orange wire,
> > > > > etcetera....
> > > > > +12`s Volts +10´s ,s volts , the yellow wire
> > marks
> > > > > +4,92 volts,....... but i cannot locate the
> > pin 3
> > > > of
> > > > > VR1 and check +5Volts, there´s a green wire
> > with
> > > > no
> > > > > power. I made also some reseating...no
> > success, I
> > > > > found 3 IC`s near the Eprom heated but still
> > you
> > > > can
> > > > > touch it with your finger not so hot..., so i
> > > > > suspect
> > > > > there`s something wrong in that zone. Is some
> > > > other
> > > > > thing to do?????
> > > > >
> > > > > greetings
> > > > > Ricardo
> > > > >
> > > > >
> > > > >
> > > > > --- Wayne Griffin <ingsoc_1979@...>
> > wrote:
> > > > >
> > > > > > Where are you located? [w]
> > > > > >
> > > > > > --- RICARDO JUAREZ <cheju_99@...>
> > wrote:
> > > > > >
> > > > > > > Yep! the problem is i don´t have any
> > > > schematics
> > > > > > nor
> > > > > > > part model for the eprom, even if it´s
> > broken
> > > > > how
> > > > > > > can
> > > > > > > i Reload the data, (i dont know anything
> > about
> > > > > > > Eproms)... my last hope of failure is the
> > > > power
> > > > > > > supply..., otherwise my emax is just a
> > piece
> > > > of
> > > > > > > garbage to be sell by pieces..
> > > > > > > a dissapointed...
> > > > > > > ricki
> > > > > > >
> > > > > > >
> > > > > > > --- Wayne Griffin <ingsoc_1979@...>
> > > > wrote:
> > > > > > >
> > > > > > > > You need to have a known good OS disk
> > and
> > > > > known
> > > > > > > good
> > > > > > > > EPROM. If you know anyone with a reader,
> > > > it's
> > > > > > time
> > > > > > > > to
> > > > > > > > pop yours out and verify it. Have you
> > looked
> > > > > at
> > > > > > > > power
> > > > > > > > supply yet? [w]
> > > > > > > >
> > > > > > > >
> > > > > > > > --- cheju_99 <cheju_99@yahoo.com> wrote:
> > > > > > > >
> > > > > > > > > Hi!:
> > > > > > > > > Finally i can make an bootable image
> > of
> > > > the
> > > > > > OS,
> > > > > > > > but
> > > > > > > > > here´s new
> > > > > > > > > symptoms: the diskette is read but at
> > some
> > > > > > > point,
> > > > > > > > > the drive stops
> > > > > > > > > the leds lights of the panel turns on,
> > and
> > > > > > then
> > > > > > > > > turns off, and again
> > > > > > > > > and again...in a continuous loop.
> > What´s
> > > > > > > happening
> > > > > > > > > maybe the diskette
> > > > > > > > > is wrong, i dont think so, because the
> > old
> > > > > > > dikette
> > > > > > > > > is loaded.
> > > > > > > > > greetings
> > > > > > > > > Rick
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > --- In emax@yahoogroups.com, "Brooks
> > > > Mosher"
> > > > > > > > > <brooksmosher@...> wrote:
> > > > > > > > > >
> > > > > > > > > > maybe a power supply issue?
> > > > > > > > > >
> > > > > > > > > > actually i have no idea what it
> > could
> > > > > be...
> > > > > > > i'm
> > > > > > > > > sort of a newbie
> > > > > > > > > here.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > On 4/23/07, cheju_99 <cheju_99@...>
> > > > wrote:
> > > > > > > > > > >
> > > > > > > > > > > Hi i´m new in the emax
> > > > stuff..recently
> > > > > I
> > > > > > > > > bought an Emax, serial
> > > > > > > > > 1000,
> > > > > > > > > > > PCb rev 2, Disk Drive working OK.
> > The
> > > > > > > Symtoms:
> > > > > > > > I
> > > > > > > > > push the ON
> > > > > > > > > Button,
> > > > > > > > > > > then it started going up,
> > everything
> > > > > looks
> > > > > > > > goes
> > > > > > > > > great "Loading
> > > > > > > > > > > Operating System" etc Etc...then
> > > > Loading
> > > > > > > Bank,
> > > > > > > > > and finally
> > > > > > > > > showing the
> > > > > > > > > > > patch on the screen, I began to
> > play a
> > > > > > > > note...a
> >
> === message truncated ===
>
> __________________________________________________
> Do You Yahoo!?
> Tired of spam? Yahoo! Mail has the best spam protection around
> http://mail.yahoo.com
>
>
[Non-text portions of this message have been removed]