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In Reply to: RE: 240hz hum through left channel posted by vkung on September 05, 2016 at 17:35:39
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．
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