Hello,
i purchased a cd17 ki signature for 270€ today...but a have a problem...on the right channel output i have a dc current from approx 40mv,my pm75 amp marantz is a dc amplifier...so....he's going in protection,speaker is not very happy!!!I ordered the service manual on the dutch audiophile site i will receive him today in pdf.If someone have the same problem plse put the response here,i am a technician in hifi audio, so i will try so find the problem very soon.🙂
i purchased a cd17 ki signature for 270€ today...but a have a problem...on the right channel output i have a dc current from approx 40mv,my pm75 amp marantz is a dc amplifier...so....he's going in protection,speaker is not very happy!!!I ordered the service manual on the dutch audiophile site i will receive him today in pdf.If someone have the same problem plse put the response here,i am a technician in hifi audio, so i will try so find the problem very soon.🙂
cd17ki
well,i try to find the location of the capacitors in the output line,but find nothing...what kind of capacitors is it?very curious....the left and right channel are inversed! on the output connectors!(red wire is on the upper cinch(L)...😕,untill now not received the service manual to download on my mail adress....so..little bit lost....i need only a part of the diagram,the output line...regards...
well,i try to find the location of the capacitors in the output line,but find nothing...what kind of capacitors is it?very curious....the left and right channel are inversed! on the output connectors!(red wire is on the upper cinch(L)...😕,untill now not received the service manual to download on my mail adress....so..little bit lost....i need only a part of the diagram,the output line...regards...
ok i find the caps the are perfect, but i have a doubt on the muting transistors,if one leaks....then you can have dc potential on the output.....can i cut them away simply?
Yes, that is a recognised problem and you can certainly remove them to try it without.
cd17ki
Ok! fixed...one transistor leaking,i remove all of them but now i must turn volume down before switch the power on or off....i know there is a better muting system with micro relays(little glass reed relay),once more thanks for the replay!😉😉😉😉
Ok! fixed...one transistor leaking,i remove all of them but now i must turn volume down before switch the power on or off....i know there is a better muting system with micro relays(little glass reed relay),once more thanks for the replay!😉😉😉😉
That's' good, an easy fix 🙂
If these two pairs of transistors are in parallel then you could always just fit one pair. (which would give probably around 90% of the muting of the two pairs). If you replace them then they do need to be of type designed for this use which have the ability to operate (at low levels) with reverse polarity on collector and emitter. Ordinary transistors will work, but won't perform as well.
If these two pairs of transistors are in parallel then you could always just fit one pair. (which would give probably around 90% of the muting of the two pairs). If you replace them then they do need to be of type designed for this use which have the ability to operate (at low levels) with reverse polarity on collector and emitter. Ordinary transistors will work, but won't perform as well.
The 2SC2878 is THE most failure prone muting transistor there is. I replace them endlessly in Nakamichi gear. The better solution, other than shunt-to-ground relay, is a good jfet, IMO, such as a 2SK117, 2SK246 or 2SK170. Work perfectly in place of 2SC2878 and no detectable leakage current even at way higher rms levels than normal.
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