Mac 1900 Transformer
- Thread starter omri617
- Start date
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It appears that if you have a Mac 1900 transformer with this type of wire arrangement on the primary side you would tie the BLK/WHT and BLK/RED wires together for a series connection.
Yes. The BLK and BLK/GRN go to the outlet. Tie the other two wires BLK/WHT and BLK/RED together and insulate them. In this manner you will have 240V capability and proper transformer phase on the input wiring.
clinic-audio
all on YAMAHA untill 1990
Hello omri617
Yes, but a 240V modification is not only this simple connections
Normally all MAC1900 were supplied with worldwide market power transformer
The connexion you are talking about are not complete
Is your problem to use original power transformer in 110V wired with 240V connexions ?
Last service manual is 039-044
What is your serial number ?
Yes, but a 240V modification is not only this simple connections
Normally all MAC1900 were supplied with worldwide market power transformer
The connexion you are talking about are not complete
Is your problem to use original power transformer in 110V wired with 240V connexions ?
Last service manual is 039-044
What is your serial number ?
omri617
Super Member
Hi
What other modifications should I do?
yes I bought a transformer from USA and I need to make it work in my country.
Serial AN2757
omri617
Super Member
Thanks
clinic-audio
all on YAMAHA untill 1990
OK but what is your country ? Israel ?
The other important modification is of course the de-emphasis because you have a receiver
The other important modification is of course the de-emphasis because you have a receiver
He has a tone control. I bet he knows how to use it. I would also think that the Israelis are more advanced that most of continental Europe and are using the newer Optimod processor where the de-emphasis time constant plays no major role anymore.
omri617
Super Member
Yes israel
What is De-emphasis? what is Optimod?
omri617
Super Member
Done.
There’s is something I’m trying to figure out and really confused.
According to schematic, at the secondary side there are :
2 brown wires
2 red wires
1 red and yellow wire (ground)
2 green wires
1 green and yellow (ground)
AND 2 Green and Red wires which I don’t have in my transformer.
My unit is the unit with the impedance selector on the back I hope i didn’t purchase the wrong transformer?
Attachments
Yes, you can. The second set of windings I believe were to lower the Voltage but still retain the current capability to the power supply. At least the is the way the schematic is drawn and what an engineer would derive from it. I recall reading that some owners were complaining of the receiver shutting down from the thermal protect with high current low impedance speakers being used. Make sense?
I needed to do yard work for a few days. I will check it out when I get the chance to see if I can answer your question.
omri617
Super Member
I can’t find 10% 8.2K Resistors
5% Would be ok?
