Hi guys,
I am trying to repair this old Pioneer for a friend of mine. No big deal, i am doing it actually just for fun and learning.
So, the amps turns on, the phones output works perfectly, no out at the speakers.
I've checked the heatsinked transistors, they should be just fine.
I've read somewhere that sometimes dust can go inside the phones jacket, closing virtually the circuit, so that the amp "thinks" that there are phones plugged in all the time. I sprayed quite a bit of air, it shouldn't be the issue.
Any hints?
Thanks guys. 🙂
I am trying to repair this old Pioneer for a friend of mine. No big deal, i am doing it actually just for fun and learning.
So, the amps turns on, the phones output works perfectly, no out at the speakers.
I've checked the heatsinked transistors, they should be just fine.
I've read somewhere that sometimes dust can go inside the phones jacket, closing virtually the circuit, so that the amp "thinks" that there are phones plugged in all the time. I sprayed quite a bit of air, it shouldn't be the issue.
Any hints?
Thanks guys. 🙂
Can you hear the relays click back when you pull the headphones out? Have you checked the voltages to the output transistors and they are ok? I just had a Sony with dirty relays that had no output to the speakers and the headphones only worked on one channel. Look up my post on this forum about it if you want, it might help.
Hi, i can't exclude that i have a problem with the output transistors, or with the voltages applied to them. I diode metered them all with the DMM, and the should be ok.
Actually i've found just one relay, for the power amp delay circuit. I hook the service manual.
Actually i've found just one relay, for the power amp delay circuit. I hook the service manual.
Any DC coming out of the speaker terminals? Oh, your amp is stereo for just one relay. Listen for the "Click" sound when you pull the headphone cord. My friend got an old Pioneer to work just by plugging and unplugging the headphone cord a bunch of times real fast.
The best thing to do when repairing someone else's stuff is to ask them what they did to break it. Lots of people don't want to tell you that they hooked 3 speakers up on each channel in parallel and turned it up all the way for an hour. Or at least ask them what the start of the problem was before it just quit working completely. If you can get any information from your friend at all, it will give you a good place to start.
The best thing to do when repairing someone else's stuff is to ask them what they did to break it. Lots of people don't want to tell you that they hooked 3 speakers up on each channel in parallel and turned it up all the way for an hour. Or at least ask them what the start of the problem was before it just quit working completely. If you can get any information from your friend at all, it will give you a good place to start.
Hey , actually i have no Dc output. Thats an important clue.
Tell me something, please... The relay, the only one, is surely part of the delay circuit , so that the power amp gets turned on late that the preamp. Is that right?
So, if i plug the headphones the signal path to the speakers kinda turns off. By what?
Because i can't hear any click plugging them in, i suppose that that relay is just for the delay circuit. Am i wrong?
It would be easier if the transistors would be shorted or so.. But as i told you, they are fine..
I'm sorry if my questions ar silly, i am kind of at the beginning of this subject.
My friend has no idea, she doesn't even know from where this amp come from!
I just thought it would be a nice occasion to start understand how to repair-troubleshooting.
Tell me something, please... The relay, the only one, is surely part of the delay circuit , so that the power amp gets turned on late that the preamp. Is that right?
So, if i plug the headphones the signal path to the speakers kinda turns off. By what?
Because i can't hear any click plugging them in, i suppose that that relay is just for the delay circuit. Am i wrong?
It would be easier if the transistors would be shorted or so.. But as i told you, they are fine..
I'm sorry if my questions ar silly, i am kind of at the beginning of this subject.
My friend has no idea, she doesn't even know from where this amp come from!
I just thought it would be a nice occasion to start understand how to repair-troubleshooting.
Last edited:
I have an older dts surround Pioneer (2005?) and when you plug a cord into the headphones jack, it throws a switch which cuts off the relays which disconnects the main speaker outs. You can hear it click when you plug them in and once again when you unplug them. If you can't hear yours it might be broke or something. You can find the solder terminals for it and bridge the in and out of the relay with a wire or something to see if it lets the amp part flow through to your speakers.
Don't give up, it's a nice simple amp to learn on and if you blow something up, it isn't important anyway!
Don't give up, it's a nice simple amp to learn on and if you blow something up, it isn't important anyway!
HiFiEngine has the service docs for this one. Largely identical to the 203, apparently.
If you are getting headphone output, the protection relay actually engages, which is good. The list of remaining possibilities is quite short:
1. Bad contact in protection relay - is there really nothing, even at elevated volume?
2. Stuck switch in headphone jack. This jack has an extra set of contacts that the speaker output is routed over, and is interrupted when headphones are plugged in.
3. Bad connection at speaker terminal or in between.
The multimeter should help identifying whether it's (2) or (3).
If you are getting headphone output, the protection relay actually engages, which is good. The list of remaining possibilities is quite short:
1. Bad contact in protection relay - is there really nothing, even at elevated volume?
2. Stuck switch in headphone jack. This jack has an extra set of contacts that the speaker output is routed over, and is interrupted when headphones are plugged in.
3. Bad connection at speaker terminal or in between.
The multimeter should help identifying whether it's (2) or (3).
Hi guys, you were right, it was a bad connection in the headphone circuit.. Probably point 2 of sgrossklass's list.
So, thanks again to all of you!
The amp sounds not that bad, actually.. I mean, nothing fancy but it's ok for some kids bedroom.. 🙂
So, thanks again to all of you!
The amp sounds not that bad, actually.. I mean, nothing fancy but it's ok for some kids bedroom.. 🙂
Well done Chi! How did you fix it? New part, blasting it with contact cleaner, Alcohol and Q-tips...?
- Status
- Not open for further replies.