Quick sx780 recap questions

[red454]

After having a total success on a complete recap of my sx580 I'm on to my 780, but after reading through several 780 threads I'm still a little unsure of a couple of things. One, which caps exactly do I want to avoid replacing that might throw off the tuner, since there is no separate board to distinguish the tuner section? It is fine so I don't need to touch it. Second, when replacing the 2 big 15mm lead spaced filter caps with 10mm spaced caps, can I simply drill 2 new holes in between the old ones on the board and just solder up the old ones? And, is it safe to replace with 10000uf caps in place of the 8000uf ones without modifying anything else? Thanks everyone, with your help I was able to successfully recap a whole receiver for the first time this week!

 

[markthefixer]

8,000 to 10,000 is ok, caps can have -20%+80% specs...

if there is room for the 10mm holes on the appropriate foils, sure. Probably 1/16" holes.

tuner caps? it IS on a small separate board. The big silver boxy thing with the movable fins.

And even some of them can (should) be replaced.

 

[red454]

8,000 to 10,000 is ok, caps can have -20%+80% specs...

if there is room for the 10mm holes on the appropriate foils, sure. Probably 1/16" holes.

tuner caps? it IS on a small separate board.

Is that whole board on the back half of the receiver that the tuning wheel sits on the tuning board? I assumed that was the power supply section and tuning altogether or is there another small board I'm missing?

 

[Uncle Bambi]

When I re-capped my SX-780, I did all the electrolytic caps on the tuner board. Be very careful around those 1001 and 3001 chips - if you accidentally blow one up (like I did), you are in for a world of hurt. They are unobtanium.

 

[red454]

When I re-capped my SX-780, I did all the electrolytic caps on the tuner board. Be very careful around those 1001 and 3001 chips - if you accidentally blow one up (like I did), you are in for a world of hurt. They are unobtanium.

That's what I wanted to do, but read if the tuner still sounds good dont worry about recapping because it could throw off the alignment, yours turned out normal though? How did you blow one of your chips by the way?

 

[Uncle Bambi]

That's what I wanted to do, but read if the tuner still sounds good dont worry about recapping because it could throw off the alignment, yours turned out normal though? How did you blow one of your chips by the way?

I was de-soldering a cap that was directly connected to the 3001 chip, and there was residual charge left in it. The tip of the soldering iron was on one lead of the cap, and something shorted causing a discharge/spark to the chip. It damaged the chip, and I had to hunt down a salvage tuner board to get a replacement. It was an expensive mistake.

Other than that mishap, it worked out ok and did not affect alignment. What I did was to replace one cap at a time and then test. If something changed, I would have replaced the last cap I changed out and stop. I did the same thing with a SX-880 I repaired - it has the same tuner board. That one worked out ok, too.

There are some caps that you don't want to mess with, but I'd have to do a search and re-read the threads to remember which ones.

 

[red454]

I was de-soldering a cap that was directly connected to the 3001 chip, and there was residual charge left in it. The tip of the soldering iron was on one lead of the cap, and something shorted causing a discharge/spark to the chip. It damaged the chip, and I had to hunt down a salvage tuner board to get a replacement. It was an expensive mistake.

Other than that mishap, it worked out ok and did not affect alignment. What I did was to replace one cap at a time and then test. If something changed, I would have replaced the last cap I changed out and stop. I did the same thing with a SX-880 I repaired - it has the same tuner board. That one worked out ok, too.

There are some caps that you don't want to mess with, but I'd have to do a search and re-read the threads to remember which ones.

I kind of want to shotgun and do all caps in there. Is the whole board on the back half of the receiver where the tuning wheel and fins are the tuning board? Where's the power supply section? I'm such a noob at looking at a board and being able to read where audio paths and power sections are.

Sent from my Kindle Fire using Tapatalk

 

[ccheath]

The power supply is on the same board (the big one) as the main amplifier and preamps as well as the protection circuit. The power supply is on the left side(when you are looking at the front) as well as the protection circuit. If you change any caps outside the signal path, you will notice little to no change to the sound quality. If you change ANYTHING in the signal path, you WILL notice the difference. As well as a pair of caps before the opamp chip and after will show big change. When you change the caps that links preamp to the main will show some change BUT there are a pair of caps in series/parallel with the low frequency switch. I haven't tried replacing only one but did replaced both so I can't comment what sound difference to expect if you use mixed brand caps in series/parallel with that switch.