If you're good it can be done with a standard iron and a small screwdriver.
Apply high quality solder liberally to both ends of the IC with a 650 degree
F iron, a long tip placed horizontally along the pins is a great help.
Alternately heat both ends of the IC, and make sure all pins are bridged
together well. Use the screwdriver to gently lift one end of the IC whilst
heating the solder- only lift it enough that solder wick will fit beneath
the pins. Wick all solder from the end you just lifted, then heat the other
end and slide the IC out of the solder, wick up all remaining solder
carefully. Then clean PCB with flux remover, and put your new IC on. I can
resolder them with a standard iron, also. It just takes good technique and
patience, as well as a gentle touch. If you apply force you'll lift traces.
You can also remove any flat pack IC with a heat gun, that takes practice
though, as if you overheat the PCB you will damage it. I know a tech in
Nashville who swears by the Weller Pyropen (Butane soldering/hot air iron)
for doing surface mount rework, he uses the hot air tip on that to do all
his surface mount work. One advantage of this is it's non-contact so you
don't have to worry about ESD, but to resolder with hot air you need solder
paste.
--
Jammy Harbin
J & J Electronics, Inc.
227 S. 4th St.
Selmer, TN 38375
731-645-3311
"Mark D. Zacharias" wrote in message
...
It is the solder connections - the new ic just runs a bit cooler. Part of
Pioneer's fix was to add a special "socket" for the new IC, but there were
problems with this.

Desoldering the IC for replacement is a problem. I use a Denon desoldering
tool, which I have discovered is no good for this job. The required
desoldering equipment is surely not cost-effective for most of us.

Mark Z.

--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Ampdoc" wrote in message
. ..
You need to replace IC9374 and change the position of the 2 zero-ohm
resistors. It's not a bad solder connection, it's a faulty ROM, the data
in
the ROM tells the DSP IC what to do. The new part is a flash EEPROM,
thus
the need to change the jumper resistors. Sometimes resoldering makes the
ROM
work a little while, but it's due to the heat. You can warm up the IC
with
a
heat gun and produce the same effect. My last couple of posts on this
unit
didn't show up, so here's another try.


--
Jammy Harbin
J & J Electronics, Inc.
227 S. 4th St.
Selmer, TN 38375
731-645-3311
"Jeff" wrote in message
...
Mark,

Thanks for the quick reply!

After I posted my earlier message, I found a discussion in the
newsgroup
about the VSX-29TX, which is basically the same model. I think you
helped
whoever asked back then also...

Anyway, that discussion set me on the right course (check the DSP
board).
I
discovered that there is audio present at the board's input, but not
its
output. Fortunately, Pioneer did a nice job silk screening the
board --
all
the connectors are labeled in a way that makes sense.

I poked around and managed to get the thing to work a few times, in
less
than the usual warm-up time. I then looked at the address (or
ata --
I
don't know) pins on the large PLCC part with my scope (is this the
SRAM?
It's Toshiba and marked like a memory) and noticed that it looked like
the
DSP is resetting a few times per second, rather than executing
continuously
as it should.

If the PLCC device is indeed the SRAM to which you're referring, I can
probably resolder it. If it's the DSP, then I'm in trouble! I don't
think
I have any chance resoldering that.

Thanks again!

Jeff

"Mark D. Zacharias" wrote in message
...
There is a known problem on these - a RAM IC needs resoldering.
Expect
a
recurrence after a year or so. Not for the novice - the foil runs at
the
IC
are too easily damaged. It is on the DSP board, but the board is no
longer
available - since Pioneer went through all of them for this problem.
For
a
while Pioneer was exchanging the receiver for a newer model - but
I'm
pretty
sure that program would have ended by now.

Mark Z.

--
Please reply only to Group. I regret this is necessary. Viruses and
spam
have rendered my regular e-mail address useless.


"Jeff" wrote in message
...
I have a Pioneer VSX-27TX receiver that works fine in all respects
except
that it takes about 20 minutes before audio can be heard from any
of
the
outputs (main or surround.) During the 20 minute "warm-up", the
display
is
active and all control functions of the receiver seem to work. I
can
use
the tuner, select inputs, enable/disable surround modes, use the
remote
control, etc. Also, signal is present at the tape output during
this
time,
but not at the preamp outputs.

Once 20 minutes (or so) has passed, the audio almost suddenly
starts
playing.

Whatever is wrong, it seems to be temperature related, as the
"warm-up"
time
is shorter if I cycle power after the receiver has been on for a
while.

Has anyone seen similar behavior from this unit? Any tips as to
what
might
be wrong? Does anyone have a schematic for this model?

Thanks,

Jeff