"Franc Zabkar" wrote in message
...
On Fri, 12 Sep 2008 06:28:31 +1000, Franc Zabkar
put finger to keyboard and composed:
I don't have a schematic but I'm assuming these resistors are
duplicated in the other channel. If so, then can't you obtain the
values that way?
BTW, the two transistors are 2SC3181N and 2SA1264N:
http://www.datasheetarchive.com/pdf-...DSA-756134.pdf
http://www.datasheetarchive.com/data...DSA0051711.pdf
The other thing that strikes me is that you replaced only one resistor
(R534) connected to the outputs. I would have thought that a typical
output stage would have two emitter resistors.
FWIW I notice that this parts list has a "0.33x2/5W" resistor:
http://parts.pioneerelectronics.com/...X-2300&x=0&y=0
Is R534 a 3-pin dual resistor ???
I just checked the schematic for a Pioneer VSX-3700S.
The emitter resistors are in fact a dual resistor (0.33 ohm x2, 5W).
The previous transistor stage has two 100 ohm 1/4W emitter resistors.
Both supply rails have 4.7 ohm 1/4W fusible resistors.
The emitter of each transistor in the penultimate stage is connected
to the base of the corresponding transistor in the final stage via a
4.7 ohm 1/4W fusible resistor.
- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.
Sorry for the multiple posts.
I e-mailed a reply but will post most of it here as well.
The circuit board layout is difficult to follow (lots of jumpers), but I
found the corresponding resistors for the other channel.
I traced the previously replaced 100 ohm resistor. It is between the emitter
of 2SC2238 (previous stage) and the center of the dual resistor.
One side of the 4.7 ohm fusible resistor is connected to the base of
2SC3181N as well as one side of the dual resistor.
That is the one I mistakenly replaced with a 4.7k ohm resistor.
I will obviously be replacing that with a resistor of the proper value and
type.
You were right on target:
"The previous transistor stage has two 100 ohm 1/4W emitter resistors."
"The emitter of each transistor in the penultimate stage is connected
to the base of the corresponding transistor in the final stage via a
4.7 ohm 1/4W fusible resistor."
Thank you again for your help.