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Harman kardon a300 rebuild

Hi everyone. I’m replacing the can capacitors on my a300 with custom built caps from Hayseed Hamfest. The hot can (cardboard wrapped) is made by GE and its specs are printed on the can as 60-100 micro farads at 350v. I’m concerned about the range of uF as I need to specify a uF rating for them to build a new one. Should I specify 100uF or something in the middle like 80uF?

thanks in advance for your responses 

ccogopher
imhififan's avatar
imhififan
2,217 posts
 

Please refer to the schematic,

There are total of three filter capacitors in its power supply: one 100µF 200V can, one 50µF 400V + 100µF 200V can and one 3X 40µF can.

Are you talking about the 50µF 400V + 100µF 200V can? It is two capacitors inside a can with 4 taps.

ccogopher OP
28 posts
 

It’s C23 on the schematic. On the schematic it’s rated as 100uF @200v but the can is rated (as per the piece of paper between the metal and the cardboard covering) 60-100uF @ 350 volts. Everything on the unit looks original although I suppose the person who owned it before me could have replaced the cap.
Now after close inspection… I see the resistor between c23 and c24 is 650 ohms instead of the 470 ohms that is shown in the schematic. The soldering looks terrible so it was probably added by someone who couldn’t find the right replacement for the capacitor. Does this seem logical? 
BTW, I’m a beginner with this.

ccogopher OP
28 posts
 

-can’t believe I didn’t notice this earlier…. Beginner mistake 

imhififan's avatar
imhififan
2,217 posts
 

Well, everyone starts as a beginner. 😊

According to the schematic I would use 100μF for C23 and C24A, higher voltage rating wouldn’t hurt either. I don’t know why 650Ω and not 470Ω, you can try both for best performance.

BTW, since you are rebuilding it, my suggestion is to replace the diodes with UF4007 to reduce noise.

 

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