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Advent 300 breaker is open need replacement

vaathi

vaathi

baski
Subscriber
Couple of months back I picked up Advent 300 for cheap and I didn't know that it was fully recapped. It was doing duty running my canton computer speakers. Most of the time my kids and myself forget to switch it off. Yesterday after short burst of static it failed to switch on. I opened it up to find it is decked with all good caps and completely restored. I have another project unit to compare to if I make any mistake. Power supply caps were bumped up and i dont see any issue. I can see the power comes in but the breaker is open. I pushed that damn red button multiple times but still breaker is not resetting. So I have couple of questions regarding the same.

Do I short the wires and see if the unit works?
If that is not advisable where can i get the breaker ( I can cannibalize the other unit, But I dont want to yet) ?
I read about putting a fuse in instead of the breaker? Is that advisable?
If all fails, what other options I have?

Thanks in advance.

Couple of pics of inside


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While its possible that the breaker itself is defective, I'm betting you have another issue in there causing the breaker to trip. While it does look like someone recapped it (and not very well I might add) those output transistors appear to be the original ones. Check the two glass fuses on the main board to make sure they aren't blown and check those output transistors and make sure they aren't shorted. If they are shorted, this could be causing the breaker to trip. If they test fine, then try removing one leg of the power source to the breaker and see if it resets then. If it doesn't reset without power to it, then I'd condemn the breaker.

Why did I say not a very good job at a recap? I'm spotting all kinds of unnecessary replacements going on in there (the huge poly caps in there come to mind) and radial caps in places where there were originally axial caps (they fit better and give the job a cleaner look when you replace caps with the same style orientation as original.)
 
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You might also want to look into the possible failure of the rectifier bridge BR1100. If that failed, it could cause a dead short tripping the breaker.
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Breaker does not reset at all.. I think the breaker is foobar. I can see 117 volt coming to the breaker line, but the other lead in the breaker reads zero. I have another unit where the breaker passes continuity test. Where can I find a break if I want to replace it.
 
The original style is going to be hard to find, unless you have a unit around for just parts. NTE has one and Parts Express offers the same NTE breaker that is a little different, but it's specs are the same. It might work with some mods to the chassis. Same specs as the original 1amp 117v breaker with two lugs coming off of it.

Here's a link to it:
https://www.parts-express.com/nte-r58-1a-manual-reset-circuit-breaker--075-142

They have a link to the datasheet for the breaker on that page that will give you dimensions and electrical specs, etc.
 
Got pulled into other things. I changed the circuit breaker and still it trips. I did check the bridge rectifier which looks like shorted on one side. I will replace the rectifier and try it again tomorrow or Monday. Circuit breaker is little too big for the space. I had another Advent 300 in project state which donated the breaker for this one. Hopefully bridge rectifier is the only problem in this fully recapped unit. I was using it as amplifier for my computer speakers.
 
Don't shotgun and just guess that the rectifier needs to be replaced. Disconnect the rectifier from the circuit to get an accurate reading. If it is good, you most likely have a shorted output transistor.
 
cademan said:
Don't shotgun and just guess that the rectifier needs to be replaced. Disconnect the rectifier from the circuit to get an accurate reading. If it is good, you most likely have a shorted output transistor.
Click to expand...
Usually shorted output transistors blow the fuses on these first, BEFORE the breaker trips. It could be one of a few possibilities in the power supply causing the breaker to trip. It could be R1100, it could be C1102, it could be something wrong with the power socket J1100 (shorted), it could be the bridge rectifier BR1100, or it could be the power filter caps C1100 & C1101 were installed incorrectly. There is also the possibility that the power transformer has a dead short in it.

My initial response earlier was that it should be the bridge rectifier, but after studying the schematic a bit, I'm leaning towards something is shorting that power outlet socket or that large resistor has an issue or the transformer itself has a problem. Why? Because the breaker is on the input side of the transformer and the rectifier is on the output side. The OP never stated if the fuses were good though......so it if they are, there is still a possibility that the output transistors are shorted. Fuses could be good still possibly due to the wrong value of fuses being installed (higher than they are supposed to be).

Lots of checks need to be done here before just shotgunning in a new bridge rectifier.
 
Before you do anything else build yourself a dim bulb tester. Whacking it with full house current every time you test it is only doing more harm and it's not the right way to troubleshoot things.
 
Issue seemed to be open and shorted Bridge rectifier. When it shorted it took out the circuit breaker. I had a donor unit and borrowed the breaker. I changed the rectifier and all is good for now.
I do have a low volume issue in the right channel. I deoxited thoroughly before putting it back. I dont see the same issue in headphone output. Another day in the ever evolving madness. BTW Thanks for all your help and suggestions.
 
vaathi said:
Issue seemed to be open and shorted Bridge rectifier. When it shorted it took out the circuit breaker. I had a donor unit and borrowed the breaker. I changed the rectifier and all is good for now.
I do have a low volume issue in the right channel. I deoxited thoroughly before putting it back. I dont see the same issue in headphone output. Another day in the ever evolving madness. BTW Thanks for all your help and suggestions.
Click to expand...

You probably have a failing output transistor in the right channel. Seen this many times where everything is ok when using headphones, but when it has to drive a normal speaker, it just can't handle it. You may want to probe the output transistors for the voltages it has on the three legs of each and compare them to the factory specs. I'll bet you find one isn't quite right.
 
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