I beleive all that switch is a secondary winding voltage selector. They give it a little less rail, for the low impedance setting. I can't say for sure on this particular Yamaha. I think that impedance switch will affect all channels wired on that power transformer.
Do you lose the right channel when the surround DSP is off? in "Direct" or "Stereo" mode? In other words, is the problem nailed down to a line stage or power amp stage problem?
Do you lose the right channel when the surround DSP is off? in "Direct" or "Stereo" mode? In other words, is the problem nailed down to a line stage or power amp stage problem?
mrshow4u said:
Just to clarify the situation so far, with my original surround speakers (6ohm) there was no output from the front right channel apart from the occasional sizzle. (Hence the title of the thread - No output).
However, when I connected some 8ohm speakers for testing purposes I found that I have normal sound from the left front channel and *distorted* sound from the right front channel.
This distortion occurs even when the DSP surround is off and the direct 2 ch stereo setting is used.
With regard to the voltages on the schematics, are these steady voltages that should be present with no signal going through the amp? i.e. No input present?
I look forward to any help anyone can give me.
This is sounding not like right and left relays, but more like "Speaker A" and "Speaker B" relay's. .......AND that the right channel is bad on both. Try this: when the Right speaker is distorting, tap the top of the relay and see if the sound improves. If it does, the relay sounds "crusty".
Grannysmith wrote:
It could be the problem, It could be something different too. So the problem is common to speaker A or B. The Right channel is bad. It could be both relays are bad in the Right channel. Speaker relays are often DPDT (double pole, double throw). Left is on one set of contacts, right is on the other set. The volume getting reduced with a distorted sound is the dead on description for an amp with "dirty" relay contacts. It definitely sounds like a poor connection. A poor contact that is current hungry will definitely cause distortion. So, where to look? If there's a headphone jack on the amp, the headphone signal might be pre-relay and run right off of the amp's output points. Listen to headphones phones pre-relay (even while the speakers are playing) Anyway, check solder connections up to the speaker relays. Check solder from the relays to the output terminals. See if tapping the speaker relay (at low or moderate volumes) induces or reduces the distortion heard of the speaker. Make sure the B+/B- (+ and - voltages sometimes called "rails")exist. These voltages should be on the Collectors of the output transistors. Look for +/- 25V~90V somewhere in there. See if tapping stuff can pinpoint the location of the failure. I know there is no wagering allowed, but I'm still thinking relay.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.