SX-780 recap list ?

[Bernardz]

Ok
I understand , the filter capacitor voltage rating should be at least 65 volts due to secondary winding in transformer.

I guess one of the reasons I choose to go with the 50 vdc KG gold’s were because oem was 50 vdc , and I think your project showed 50vdc filter capacitors, numbers were a little blurred , i might of read it wrong .

Surprisingly enough, I actually purchased the Nichicon LKS1J822MESB capacitors (listed in attachment) , 8200 mfd 63vdc, but was going to return them tomorrow because in your project , I thought it showed 50 vdc , not 63vdc…

Plus 8200 mfd @63vdc Nichicon does not come in Gold or KG Models only the 50vdc.

I haven’t installed any filter caps yet , going to install them next week when my new soldering iron arrives from Amazon .

I totally understand and cap not sitting right on the PCB board , if I use the LKS1J822MESB caps will both + and - terminals on the snap capacitor fit into the holes, or will I have to do some re-engineering like you did in your project?

Terminal spacing on caps are 10 mm, I think the spacing on PCB from + to - is a tad bit longer .

Can’t express my appreciation enough for sharing your knowledge with me ,
I’m preparing this unit for my older brother as a gift for always being there for me growing up .
Keep in mind , I’m 65 my older bro is 68.
I know he’s going to really like this unit when we’re done

 

[mgrisoli]

Ok
I understand , the filter capacitor voltage rating should be at least 65 volts due to secondary winding in transformer.

I guess one of the reasons I choose to go with the 50 vdc KG gold’s were because oem was 50 vdc , and I think your project showed 50vdc filter capacitors, numbers were a little blurred , i might of read it wrong .

Surprisingly enough, I actually purchased the Nichicon LKS1J822MESB capacitors (listed in attachment) , 8200 mfd 63vdc, but was going to return them tomorrow because in your project , I thought it showed 50 vdc , not 63vdc…

Plus 8200 mfd @63vdc Nichicon does not come in Gold or KG Models only the 50vdc.

I haven’t installed any filter caps yet , going to install them next week when my new soldering iron arrives from Amazon .

I totally understand and cap not sitting right on the PCB board , if I use the LKS1J822MESB caps will both + and - terminals on the snap capacitor fit into the holes, or will I have to do some re-engineering like you did in your project?

Terminal spacing on caps are 10 mm, I think the spacing on PCB from + to - is a tad bit longer .

Can’t express my appreciation enough for sharing your knowledge with me ,
I’m preparing this unit for my older brother as a gift for always being there for me growing up .
Keep in mind , I’m 65 my older bro is 68.
I know he’s going to really like this unit when we’re done

First let me address the cap choice, my BOM (bill of materials) list shows the 63v not the 50v.
Not sure if took the photos before or after replacing the caps, perhaps before that is why you noticed 50v there.
If you already have your 50v that is fine you can use them and they will work.

Here is some food for thought for future projects...
The "muse", fine gold (FG) or any other audio specific caps are excellent for audio path (places where actually music will pass through them).
Trade offs are that they cost more, work temperature will be lower and will have shorter lifespan (hours).
So, for power supplies (or any current path) it is tottally fine if your choice is more robust capacitors able to handle harsher conditions of overwhelming temperatures and voltages higher than expected.
That will allow you better specs in terms of lifespan and work temperature if you pick a different Nichicon line such as UPW and UHE and then UKL (for low leakage) which also cost less.

I do not remember if the LKS1J822MESB is a drop in (sorry if I am contradicting myself, this was too many receivers ago).
Best approach is to pull the datasheet and look at the lead spacing there.
Getting use to decipher these datasheets is an important part of the job, but again, I am not suggesting you to not use the caps you already acquired, just dont afraid of punching new holes in the PCB if you feel like that would make a better assembly.

 

[Bernardz]

Man that’s some really go info ,
You don’t necessarily need to use audio grade caps for filter caps , primarily for audio path ,

I think I’m going to research the filter cap install again. I may return both the 50 and 63 volt caps to Digi-Key and mouser .
Look for a longer hour and higher temp component , and with the lead spacing a bit wider if possible . A capacitor that is meant to reside in power supply environment.

So if I’m looking for a suitable capacitor, I should be looking for a 65 vdc ?
What voltage should I not exceed ?
Also , 8000 mfd is specified oem , can I go over , how much should I not exceed in capacitance?

Thanks again
Bernard

 

[mgrisoli]

Man that’s some really go info ,
You don’t necessarily need to use audio grade caps for filter caps , primarily for audio path ,

I think I’m going to research the filter cap install again. I may return both the 50 and 63 volt caps to Digi-Key and mouser .
Look for a longer hour and higher temp component , and with the lead spacing a bit wider if possible . A capacitor that is meant to reside in power supply environment.

So if I’m looking for a suitable capacitor, I should be looking for a 65 vdc ?
What voltage should I not exceed ?
Also , 8000 mfd is specified oem , can I go over , how much should I not exceed in capacitance?

Thanks again
Bernard

A notch higher than original specs should be fine, from 50v the next step would be 65v. and from the 8000mF if you go up to 10000 that would be fine too.
Just don't go crazy about it, I think this receiver does not have an in rush current protection, so if you increase your filter caps too much it may overwhelm your transformer when you turn it on. As you go throught he options don't forget to observe the dimensions as well, diameter and height cannot exceed the clearance you have to install them.

 

[Bernardz]

Thanks for update
After talking and learning from you , I’m going to return the Nichicon KG and LS series capacitors back to Mouser because the hours are only 1000 plus temp is rated at 85deg C, and I don’t need audio grade capacitors for a power supply .

I actually had 2-each Nichicon 10000 mfd 50 vdc radial lead capacitors and they were 25 mm, it would fit perfect in the solder holes on the PCB without having to modify anything else, but the voltage was only 50 vdc and they seemed very flimsy , the leads on the capacitor looked like it would struggle to carry ampacity thought the circuit without the tiny capacitor leads really heating up . Just my thoughts , I could be wrong .

I called Mouser because I just got tired of all the small print and reading all the possible fits for my application ,
Here is what they found

Rubycon
8200 mfd, 63vdc, 105 deg C, 3000 hours, 30 mm wide , 40 mm high, 4.04 amps ripple current , snap in terminals
Or,
Rubycon
10000 mfd, 63vdc, 105 degsC, 3000 hours, 30 mm wide , 45 mm high, 4.45 amps ripple current , snap in terminals .

I’m going to have to modify PCB in either case, so
In your opinion ,
Which of the two capacitors will be the best to install on my SX780 power supply board .
Thanks
Bernard

 

[mgrisoli]

The 10000mF would be my pick between those two if the additional height is not a problem.

 

[Greg64]

Saying a thank you to all to keep this thread breathing.

 

[KKnight]

Almost done recapping+ a 780. Seeing a lot of probs ppl have w/ the emitter resistors by the Darlingtons. All 4 of of the marked 0.22 ohm 2w resistors read .7~.8 ohms on my lowest 200 DMM scale in or out of the board. Misread? Problems?

 

[punchback]

Did you subtract the resistance of the leads?

 

[AndyCares]

Great thread thank you!!