REQ: Pioneer SX-2300 component values, other help

To anyone that can help, I would like to get the values of R550 and R338. I think I might have replaced one of them with a resistor of the wrong value

History: Replaced R534 and 2 shorted power transistors connected to it. (C3181N and A1264N) Replaced burned R538 with 100 ohm, 1/4 watt resitor. Replaced burned unreadable R550 with 4.7k (4700) ohm resistor. Checked neighboring resistors, transistors.

Problem now: Stereo comes on, relay clicks on, display and controls work. Very low volume and distorted audio is all I get. I have to turn it most of the way up and can barely hear it.

Thanks!

Reply to
Mikeydude
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Both channels ? That model hasn't by any chance got four RCA (phono) jacks on the back marked "processor" or something similar has it ? Often have a 'bar' silk screened across them to indicate that they should be bridged. Very low audio on what appears to be an otherwise working amp, is the typical symptom for the bridging pins being missing. I have had many amps that have been bought on eBay or at boot sales over the years, brought to me for this 'fault'.

Arfa

Reply to
Arfa Daily

Or the Tape Monitor (or "Tape 2") switch engaged...

Mark Z.

Reply to
Mark D. Zacharias

Let me try this again :

To anyone that can help, I would like to get the values of R550 and R338. I think I might have replaced one of them with a resistor of the wrong value

History: Replaced R534 and 2 shorted power transistors connected to it. (C3181N and A1264N) Replaced burned R538 with 100 ohm, 1/4 watt resitor. Replaced burned unreadable R550 with 4.7k (4700) ohm resistor. Checked neighboring resistors, transistors.

Problem now: Very low volume and distorted left channel audio.

Thanks!

Reply to
Mikeydude

Oops! I was tired and didn't check it out thoroughly. (The repair has been on hold for a long while, just replaced R534 last night.)

I'm only having a problem with the left channel.

Thanks for the help!

Reply to
Mikeydude

Oops! I was tired and didn't check it out thoroughly. (The repair has been on hold for a long while, just replaced R534 last night.)

I'm only having a problem with the left channel.

Thanks for the help!

Reply to
Mikeydude

On Thu, 11 Sep 2008 06:40:15 -0500, "Mikeydude" 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:

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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:

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Is R534 a 3-pin dual resistor ???

- Franc Zabkar

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Please remove one \'i\' from my address when replying by email.
Reply to
Franc Zabkar

On Fri, 12 Sep 2008 06:28:31 +1000, Franc Zabkar put finger to keyboard and composed:

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

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Please remove one \'i\' from my address when replying by email.
Reply to
Franc Zabkar

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.

Reply to
Mikeydude

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