Emax

Ok, i\ufffdll put it soon, 
thanks
saludos

--- ted Summers <djtbs1@...> wrote:

> I need more description (do the connectors have
> labels next to them  
> like CN14 or J1), to tell you what the connectors
> are for. Picture  
> Files do not show on the group email, but you could
> post them to the  
> files and then we could see what you are talking
> about, also.
> 
> Thanks,
> Ted
> 
> On Apr 29, 2007, at 1:18 AM, RICARDO JUAREZ wrote:
> 
> > Well...
> > I clean all the unit,everything was removed, and
> found
> > nothing special, nothing but a few problems with
> some
> > "Light leds" in the push buttons, there was one
> with a
> > "cold soldering", and some contacts with several
> > wearing, I repair it with some glue and new
> metalics
> > contacts, ONe Question: There\ufffds a pair of "sort of
> > jacks" (white and light-Blue) in the back of the
> > keyboard plaque, in one side and the other side,
> is
> > there any cable attached to they??? because my
> unit
> > has no one........I will check the soldering in
> the
> > PSU...
> > Saludos
> > Ricardo
> >
> > --- Wayne Griffin <ingsoc_1979@...> wrote:
> >
> > > I agree about the 5.05V and the idea of a
> voltage
> > > drop
> > > across the digital board.
> > >
> > > orange = +12V
> > > yellow = +5V (5.05V)
> > > purple = -12V
> > >
> > > The +10V on pin 3 of Q2 is also fine because
> that's
> > > either to drive the DC/DC converter for the LCD
> > > backlight or maybe something pertaining to the
> > > EPROM.
> > > [w]
> > >
> > >
> > >
> > > --- ted Summers <djtbs1@...> wrote:
> > >
> > > > 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????
> > > > > M\ufffds 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
> 
=== message truncated ===


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