Onkyo M-504/M-508 main filter cap mod

[itsikhefez]

Hi,

The original filter caps used on the Onkyo M-504/M508 used 4 pins with irregular spacing and this part is unobtainable AFAIK.

To my understanding 2 pin caps are fine functionally but they simply cannot be fitted into the original holes. Some folks have found various "hacks" but I'd like to do something more elegant, especially since there are 8 caps and something can go wrong.

I was thinking about making a circular PCB in the diameter of the original cap, where a standard 2-pin can be soldered onto, and it would have 4 pins in the original spacing. In this case 8 PCB's would be used.

Another option is to have a single rectangular PCB, where all 8 caps will be soldered on to. The PCB will can then have pins soldered on the bottom, or attached with standoffs and connected via wires to original locations.

I've never designed a PCB and have no idea where to start.
Is this a good idea? bad idea? Anything else to consider?

Thanks!

 

[ubergeeknz]

Drill holes. Bend pins to existing pad(s). Job done.

 

[itsikhefez]

Yea, I am a bit reluctant to drill holes... afraid to screw up
Just bending 2 pins won't be sufficient though, as all 4 pins were used in the original PCB. I would then have to jumper to the other pin.

Not incredibly difficult but was thinking a conversion PCB would be more elegant and less error-prone

 

[ubergeeknz]

Are you sure about that? Got the board out to look at the underside?

 

[itsikhefez]

I haven't done the work yet but yes based on reading about this in other forums...
This link has alot of good photos

 

[ubergeeknz]

They're very close together. A solder bridge would do it.

 

[Andersonix]

You have my sympathy!

But why would Onkyo split it all up like that?

 

[itsikhefez]

I have no idea... and all the folks that attempted to fix this have asked the same question.

The unit I have is stuck in protection, so I need to fix that regardless and I doubt the issue is with the main filter caps.
I was planning on replacing all electrolytics as the amp is ~25 years old but perhaps I'll replace all except those main filter caps

 

[uchu007]

I have no idea... and all the folks that attempted to fix this have asked the same question.

The unit I have is stuck in protection, so I need to fix that regardless and I doubt the issue is with the main filter caps.
I was planning on replacing all electrolytics as the amp is ~25 years old but perhaps I'll replace all except those main filter caps

I drilled and it's going well I think it's the best solution! Here is a photo with the capacitors installed

 

[ubergeeknz]

Looks tidy, nice job

 

[uchu007]

Looks tidy, nice job

Thank you, before wanting to pierce I designed cards to adapt without piercing but it brings more problem car to the card + the height of the new capacitors was too high! So I got started I perceived and its going very well like its

 

[itsikhefez]

I drilled and it's going well I think it's the best solution! Here is a photo with the capacitors installed

I'm not sure I fully understand what you did here.
Would it be possible to draw arrows on the pins of the new caps (BTW, which caps did you use?) and where you drilled?
Thanks!