Hi,
a solid state input selector!
Is it worth saving/resurrecting?
What about inserting a real switch selector and hard wiring the switch output into the PCB after that Tosh chip? (That is deliberately derogatory!)
Or
making up a relay switching selector PCB?
There's sufficient room in there for many projects!
a solid state input selector!
Is it worth saving/resurrecting?
What about inserting a real switch selector and hard wiring the switch output into the PCB after that Tosh chip? (That is deliberately derogatory!)
Or
making up a relay switching selector PCB?
There's sufficient room in there for many projects!
MCM has the TC9273N... you would have to look at the datasheet(s) to see what the 010 buys you.
http://www.mcminone.com/search.asp?...t.x=7&btnSubmit.y=6&btnSubmit=GO&searchin=off
http://www.mcminone.com/search.asp?...t.x=7&btnSubmit.y=6&btnSubmit=GO&searchin=off
i'm beginning to hate soft switching..........
had a kenwood receiver with a lightning hit. after replacing the 12v standby xfmr, found out the processor was shorted and the power relay coil was open. after replacing those, found out the input selector chips were bad.... at that point the customer said "forget it"...... his old '70's kenwood receiver that he brought in at the same time had a bad regulator transistor, and that was it.....
the version numbers may be firmware revisions.... try to get the correct one if you can, otherwise the chip might "miscommunicate" with the processor or control panel keyboard.
had a kenwood receiver with a lightning hit. after replacing the 12v standby xfmr, found out the processor was shorted and the power relay coil was open. after replacing those, found out the input selector chips were bad.... at that point the customer said "forget it"...... his old '70's kenwood receiver that he brought in at the same time had a bad regulator transistor, and that was it.....
the version numbers may be firmware revisions.... try to get the correct one if you can, otherwise the chip might "miscommunicate" with the processor or control panel keyboard.
Pars: Thanks! Have been looking everywhere for that (obviously not...)
Unclejed613: Yes they seem to be very fragile.
I have done some troubleshooting, please tell me what you think.
I started by leaving the amplifier off, and disconnecting the preamp from the amplifier by removing the 'whatevertheyarecalledinenglish' from the rca-sockets om the back.
I connected a signal source (cd-player playing Guns n' Roses) and started to do some measuring with my oscilloscope.
1. The amplitude of the signal seems to be a bit stronger on the input where the signal source is connected, but I got a bit confused because of the relatively high amplitude on all inputs.
However, I noted that on all the other inputs, the amplitude is weaker on the negative side.
2. Still with the amplifier off.
I measure the signal on the inputs of the TC... I discover that the signal is strongest on the input corresponding to the rca input to which the signal source is connected.
3. Amplifier on...
I now get identical signals on all of the rca inputs and on all of the TC... inputs.
4. I measure on the pre out rca connectors and find out that I get the same signal no matter which input is activated (not surprising according to #3).
5. The TC... is switched by sending 18 bits serial data through the 'Data' pin. Kind of hard to measure (with my low end el cheapo oscilloscope), but at least I can see that there is some kind of activity going on every time I switch inputs.
Also, if I connect the oscilloscope to the pre out connectors there is a small interrupt in the signal each time I switch input. This must mean that the TC... at least gets a Data signal, but does not manage to do the correct switching.
Conclusions
With the amplifier off, at least there is a measurable difference between the selected input and the other inputs.
With the amplifier on, all the inputs get connected together. The TC... gets Data signals when switching inputs, but it seems like all inputs gets connected together.
It has to be the TC... that's the faulty part.
Or am I wrong?
Unclejed613: Yes they seem to be very fragile.
I have done some troubleshooting, please tell me what you think.
I started by leaving the amplifier off, and disconnecting the preamp from the amplifier by removing the 'whatevertheyarecalledinenglish' from the rca-sockets om the back.
I connected a signal source (cd-player playing Guns n' Roses) and started to do some measuring with my oscilloscope.
1. The amplitude of the signal seems to be a bit stronger on the input where the signal source is connected, but I got a bit confused because of the relatively high amplitude on all inputs.
However, I noted that on all the other inputs, the amplitude is weaker on the negative side.
2. Still with the amplifier off.
I measure the signal on the inputs of the TC... I discover that the signal is strongest on the input corresponding to the rca input to which the signal source is connected.
3. Amplifier on...
I now get identical signals on all of the rca inputs and on all of the TC... inputs.
4. I measure on the pre out rca connectors and find out that I get the same signal no matter which input is activated (not surprising according to #3).
5. The TC... is switched by sending 18 bits serial data through the 'Data' pin. Kind of hard to measure (with my low end el cheapo oscilloscope), but at least I can see that there is some kind of activity going on every time I switch inputs.
Also, if I connect the oscilloscope to the pre out connectors there is a small interrupt in the signal each time I switch input. This must mean that the TC... at least gets a Data signal, but does not manage to do the correct switching.
Conclusions
With the amplifier off, at least there is a measurable difference between the selected input and the other inputs.
With the amplifier on, all the inputs get connected together. The TC... gets Data signals when switching inputs, but it seems like all inputs gets connected together.
It has to be the TC... that's the faulty part.
Or am I wrong?
I bought a C340 with the same diagnosis. I trust your analysis and googled and found the TC9273N-010 at www.impelshop.com. I ordered a single chip - it was shipped today. Now I hope it is the right fix
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