Need help replacing caps. Totally new to this

[Coleman]

I have a cec amp5300 that has a left channel problem. Took it to a shop and the quote to fix it was 700-900$. The caps are 2200uf 35v And there are 62 per channel. I opened it up and most of the caps look ok but many are crowning severely and the repair shop said there was some fluid leakage.
He recommended to just replace all of the caps in the entire unit as they are cheap and will eventually go the same way.

So I have zero experience but how difficult could it be to replace the caps? Surely it will be time consuming to replace 124 though. But I am in no hurry.

So I need help. What do I need to know in order to pull this off?

Thanks so much for any insight and expertise you may be able to give me!

Coleman

[Ron AKA]

How old is this amp? I'm thinking if it is relatively new these capacitors should not have failed due to age. If not age, then what caused them to fail? Over voltage would be the most common reason.

I saw a photo of this amp and I count 32 caps the same size. Are there 4 layers of them? Or how do you get up to 62 per channel?

For a power supply reservoir and filter 35 volt capacitors seem too low in rating. I would have expected 75 volts or higher. I suppose they could be pairs connected in series, but that would not be a great idea as that would half the capacitance, and double the series resistance. Can you determine how they are wired relative to the power supply, and what voltage they are operating at?

Normally replacing capacitors is not difficult if you can solder. Are they soldered to a board or are they snap in? Snap in would be easier still.

That said, I think you need to find out first why they failed. You need to be sure replacement caps have a high enough voltage rating, and also ripple current rating.

[Coleman]

there are 32 caps per channel. not all of them are failing. only about 15 total. as far as why they failed, it would probably have to with the fact that i would occasionally trip the protection circuit by listening too loudly. coupled with the fact that the caps are poor quality, that in my mind could be the reason.

i am a total beginner so i have no idea how this stuff works, so i can't answer your question as to how they are wired relative to the power supply. i don't know what the power supply looks like. is that the toroidal transformer? how would i determine that?

if they are soldered, how do i remove the caps from the board?

[Coleman]

oops, i just realized there are 62 caps total. 32 per channel

[DF96]

Learn how to solder. When you have mastered that, learn how to de-solder. Learn a bit about how PSUs work - enough to keep you and the equipment safe. Then think about doing the repair yourself.

[ingenieus]

I wonder what the designer's reasoning was when fitting all those caps?

[Mooly]

Replacing caps is perhaps only part of the problem.

If there is leakage you need to be confident to be able to clean that up. Detailed photos of the damage would help.

Replacing the caps is straightforward as long as you can access the soldered joints easily. A hot large tipped iron and some desolder braid is all you need. It takes around one second per joint to desolder and the cap should lift cleanly out. I assume the boards are not "double sided" with soldering and print on top and bottom as that makes it more difficult unless you are used to them.

What is the fault on the amplifier ? (beside obvious bulging caps)

[Ron AKA]

Originally Posted by Coleman

there are 32 caps per channel. not all of them are failing. only about 15 total. as far as why they failed, it would probably have to with the fact that i would occasionally trip the protection circuit by listening too loudly. coupled with the fact that the caps are poor quality, that in my mind could be the reason.

It is not making sense to me that you can have 30 volt capacitors in a 100 watt amp. Is it possible they are 300 volts? I believe this amp is a single ended class A. You may have better luck with responses if you post in the Pass section of this forum.

The capacitors only store power. They do not produce it, and I don't believe can be over loaded. Although it seems possible if you run the amp so hard that the power supply can't keep up, then the ripple current could increase significantly and kill the capacitor.

Seems to me you need a circuit drawing of the power supply to make any sense of this. For sure you need the voltage rating of the cap to be high enough, as well as the ripple current capability. Do you have a manufacturer name and part number on the capacitor? That may help.

[cbdb]

It is not making sense to me that you can have 30 volt capacitors in a 100 watt amp.

Probably 16 caps per rail in some series parallel combination (a 8800uf, 60 volt equivalent cap is easy to make)

Would make sense, if the manufacturer already had the caps otherwise its kinda strange.

Schematic? I would love to see how they wired 32 caps for one channel.

[stratus46]

Originally Posted by Coleman

I have a cec amp5300 that has a left channel problem. Took it to a shop and the quote to fix it was 700-900$. The caps are 2200uf 35v And there are 62 per channel. I opened it up and most of the caps look ok but many are crowning severely and the repair shop said there was some fluid leakage.
He recommended to just replace all of the caps in the entire unit as they are cheap and will eventually go the same way.

So I have zero experience but how difficult could it be to replace the caps? Surely it will be time consuming to replace 124 though. But I am in no hurry.

So I need help. What do I need to know in order to pull this off?

Thanks so much for any insight and expertise you may be able to give me!

Coleman

You really need to learn to walk before trying to run. Zero experience? I predict failure regardless of how careful you are because you don't even know what careful means yet. You want to learn on a $1600 rig? I STRONGLY recommend finding an experienced tech to work with you and guide you while it's all still possible.

Static discharge can destroy digital chips. There may be specific assembly/disassembly sequences. You DO have the service manual, right? Lifted pads and damaged plate throughs can ruin the amp or maybe _only_ cripple it. It takes some time to learn this.

Even your tools may not be up to this task. I'd be comfortable using my Metcal iron on it but only because I've been doing this for 40 years and have replaced thousands of capacitors in machines that cost $100K or more.

I do mean to rain on your parade but only to preserve the rig. You'll learn but there are a lot of subtleties you're not aware of yet.

G²