Welcome! Need support, you got it. Or share your ideas and experiences.
In Reply to: RE: 240hz hum through left channel posted by Michael Samra on September 05, 2016 at 16:41:40
I will give this a try when I get home and let you know.
I'm on power from west JP so 100v 60hz.
Thanks for your help
I have not tried tube rolling, however I swapped the tubes on left and right side to see if it was related to the hum, however this made no difference
I will check Q3 & Q5. If both Q3 & Q5 are ok... you need to check each soldering point on the left channel.
While checking your suggestions Q3 & Q5... I was double checking everything around this area and noticed that Zenner Diode ZD1 is allowing current to flow through both directions.
Seems like this may be an issue! > . <
I will replace today and report if issue is corrected.
Thank-you for all your help.
yes.. Once you replace the FET... it will solve your problem.
You need to replace or check your left channel's output tube.
I will replace Q3 and Q5 with 02N60Z
Is there a specification for Zenner Diode, in assembly instruictions it is only refered to as Zenner Diode with no more detailed information.
YOU DON'T NEED TO REPLACE THE DIODE.
I have replaced Q3 (did not replace diode)
Still getting hum occuring on left channel.
Also re-soldered every connection. Should i Also replace Q5?
CHECK THE VOLTAGE AS PERV Page 19
All points voltage checks ok
Any other tips?
where you bought your kit?
99% is the soldering issue..
I removed all components related to power filter, added new FET for Q3 / Q5, and resoldered everything. HUM is solved.
Thank-you for your help.
Ｉ ｗｉｌｌ ｒｅｐｌａｃｅ Ｑ3 Ａｎｄ Ｑ５
Ｉｓ ｔｈｅｒｅ ａ ｓｐｅｃｉａｌ ｚｅｎｎｅｒ ｉ ｍｕｓｔ ｒｅｐｌａｃｅ ｗｉｔｈ． ＴＵ－８２００ ｉｎｓｔｒｕｃｔｉｏｎｓ ｓｉｍｐｌｙ ｃａｌｌ ｉｔ Ｚｅｎｎｅｒ Ｄｉｏｄｅ ｗｉｔｈ ｎｏ ｆｕｒｔｈｅｒ ｓｐｅｃｉｆｉｃａｔｉｏｎ．
Thank you I will check
Then your hum would be 120hz from the power supply just like the US
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
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