Mark 3 Receiver Hum

[xtremeflyr]

???I am not an expert by any means, just enough knowledge to get me in trouble. My Mark 3 receiver has developed a hum through the speaker when I turn it on. Wanting a longer ping, I installed 4 each 20uf caps where the 47uf cap used to be. Positive to positive and negative to negative ends. I have used the Mark 3 for around 2 months with the 80uf caps in. Yesterday, when I turned the receiver on, there is a hum coming through the speaker.

I was was warned not to exceed 47uf, but did. Dumb to go against the advice of the forum I now realize. I do not have the proper test equipment to search for what may be wrong. Just a DMM and a soldering iron.

The caps are the only new parts I had installed. Nothing more was done. I understand it may be one thing and a lot more that happened to cause the hum in the receiver. I am asking if the caps I soldered in may have caused this, or, if it is something else.

Please be easy on me, but, any advise reply will be taken constructively. Thanks...and PM or email me.

[gator7]

Just a guess I my part, but it is possible that the longer ping may have sressed the 3 stage 450 volt can. And now it has started to go bad.

[xtremeflyr]

Thanks for the reply gator7. About the 3 stage 450 volt can that may be stressed, where is it located? Would replacing that can help? Or is it a lost cause. Like you, I am only guessing.

[Tombstone (R.I.P.)]

gator7 is right, that capacitor is probably the culprit. It's the large can on the receiver deck and the values are marked on the side. It's a twist lock mount and easy to replace. The ping caps may have helped cause the problem, I'd go back to the 47 uf cap.

Tombstone

[gator7]

Thanks Tombstone, Well the cap is on the top side. Looking from the face plate, it is in the back right. Yes it should fix the issue with the hum. The cost of this can is 35.00 to 45.00 plus shipping.
Be aware of the high voltage of this can. 450 volts can leave a mark.

73