Nad c-541i
Yes i will do that , how can i be sure if those relays are ok is it possible to some how measure them?
thx
Yes i will do that , how can i be sure if those relays are ok is it possible to some how measure them?
thx
When the relays are closed (player on and playing) the voltage coming out of the relay should be the same as that going in.
Nad c-541i
If the relays are bad is there any replace part for that because i see these part only on some china store i think it is this one acording to service manual:
BESTAR BT-12S Relay (2P2T, 12VDC, 960£[) - WECL Online
thx
regards
If the relays are bad is there any replace part for that because i see these part only on some china store i think it is this one acording to service manual:
BESTAR BT-12S Relay (2P2T, 12VDC, 960£[) - WECL Online
thx
regards
I wouldn't suspect the relays at this stage. You would have to physically measure the size of them and check the pinouts to pick a replacement. You would also need the coil voltage and approximate coil resistance.
Last on the list of suspects at this stage.
Last on the list of suspects at this stage.
Nad c-541i
So far nothing new i cant get 12v to op amp friend have some spare regulators lm317 and 337 also l7808 and 7805 but changing them nothing resolve we inspected botom side of board there were some resoldering made , i measured also rectifing diodes and have some readings around 0,1 those diodes that come for analog section.
thx
regards
So far nothing new i cant get 12v to op amp friend have some spare regulators lm317 and 337 also l7808 and 7805 but changing them nothing resolve we inspected botom side of board there were some resoldering made , i measured also rectifing diodes and have some readings around 0,1 those diodes that come for analog section.
thx
regards
You are not measuring the right things and just changing parts won't fix it.
You should have around 15 volts AC on each end of fuses M512 and M513.
That voltage should appear on the bridge rectifier. Just follow it through the relay to the diodes and measure. The output of the bridge should be around plus and minus 18 to 22 volts DC give or take. That is the same as reading the voltage across C506 and C507.
So six points in total to take readings at. Two fuses, the input to the bridge, and the two caps.
What have you got ?
You should have around 15 volts AC on each end of fuses M512 and M513.
That voltage should appear on the bridge rectifier. Just follow it through the relay to the diodes and measure. The output of the bridge should be around plus and minus 18 to 22 volts DC give or take. That is the same as reading the voltage across C506 and C507.
So six points in total to take readings at. Two fuses, the input to the bridge, and the two caps.
What have you got ?
Nad c-541i
Ok will measure a litle later because i have it in my friends place sorry for bothering you but how it looks that bridge rectifier and also one thing do i ned to make measure from the bottom of the board or can i take measures from the top where the components are visible.
thx
Ok will measure a litle later because i have it in my friends place sorry for bothering you but how it looks that bridge rectifier and also one thing do i ned to make measure from the bottom of the board or can i take measures from the top where the components are visible.
thx
Nad c-541i
There are no 15v on fuses , after closer look there are some fizikal damages on toroid trafo and acording to specs on it all readings are ok except the middle one there is no 13v as it should be.
thx
regards
There are no 15v on fuses , after closer look there are some fizikal damages on toroid trafo and acording to specs on it all readings are ok except the middle one there is no 13v as it should be.
thx
regards
You need to be sure. Put your meter on AC voltage and have the black lead connected to ground. You should then read the AC voltage on both ends of both fuses.
If you are 100% sure it is not present then either the transformer winding is damaged or there is some wiring/print damage from the transformer to the fuses.
If you are 100% sure it is not present then either the transformer winding is damaged or there is some wiring/print damage from the transformer to the fuses.
OK, so if you are sure on your readings then it can only be the transformer that is faulty (which I would still be surprised at tbh).
(But if you have done the measurements then there is no other possibility)
(But if you have done the measurements then there is no other possibility)
Nad c-541i
I found a company in our country they will build a new trafo on the specs of old one for cost arround 17€ will report when i got new one installed.
thx
HITELEKTRONIK d.o.o.
I found a company in our country they will build a new trafo on the specs of old one for cost arround 17€ will report when i got new one installed.
thx
HITELEKTRONIK d.o.o.
OK 🙂 I should say good luck but I still can't quite believe the transformer is open circuit or faulty but if you are sure , sure, sure and 100% sure there is no 15 Vac present on those windings...... its the transformer.
nNad c-541i
there was 100% no such voltage on fuses and not even on trafo where it should be minimum 13v as it state on trafo.
there was 100% no such voltage on fuses and not even on trafo where it should be minimum 13v as it state on trafo.
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Nad c-541i
Transformator is repaired and player is back in work. THX @Mooly for all the help.
regards
Transformator is repaired and player is back in work. THX @Mooly for all the help.
regards
Just read through this thread as I have a modified (various tweaks) NAD C540. It just goes to show that a systematic approach to fault finding (nearly) always wins the day over a blind stab in the dark. I am an aircraft electrical engineer by trade. Often, experience guides fault finding based on system knowledge. This is alway backed up by measurements using the split-half method. Ocasionally we come across a fault that stumps us, but we all too easily discount things because they "never fail". A valuable lesson to us all.
Regards,
Chris.
Regards,
Chris.
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