I have a JL 1000/1 here that seemed to have 2 of its 8 B+ filter capacitors exploded its guts out. theres pieces of paper/film scattered about the amplifier.
Otherwise, the amp seems to work fine at lower powers. I have no idea what caused this.
So before I change out all these caps and have them explode in my face, Has anyone happened to have run into this before? and know a potential cause and resolution?
Wonder if it was a bad speaker load impedance or something else.
Otherwise, the amp seems to work fine at lower powers. I have no idea what caused this.
So before I change out all these caps and have them explode in my face, Has anyone happened to have run into this before? and know a potential cause and resolution?
Wonder if it was a bad speaker load impedance or something else.
Did you check ALL of the PS FETs? This supply is different and can have just 1/4 of the FETs fail. The supply may actually seem to be functioning normally.
I'd also check for bad connections on the various bussbars. Check carefully top and bottom.
I'd also check for bad connections on the various bussbars. Check carefully top and bottom.
I did a quick check and found no shorts, but I havent done anything thorough with the FETS such as looking for leakage, or breaking down under load.
Typically when PS fets fail the gate resistors get smoked as well, so if you don't see any bad gate resistors the silicon is likely good too. Could be that the pair of caps that failed were simply old and let go? These amplifiers are going on 20 years old by now, and the chinese caps back in those days weren't exactly known for their high quality. I have a 250/1 here that exploded its input capacitors because the factory neglected to do QC and several of the fets had long leads touching the case that caused a dead short as soon as power was applied.
Yea I keep forgetting, these are starting to reach into the "old school" territory. shudders...
And nothing is smoked as far as I can see. Could be the drive transformers, but ive only ever had to replace those once, and it was from a parts unit.
And nothing is smoked as far as I can see. Could be the drive transformers, but ive only ever had to replace those once, and it was from a parts unit.
Old doesn't necessarily mean bad. I don't want to contaminate this thread with an argument about caps but at the same time, I don't want a bunch of people who have old amps to start changing caps for no reason, often doing more damage than anything else.
Its not that old school is a bad thing. That's not it at all, FWIW, I still run CRTs as daily drivers. They are built to last, tend to have a bit better build quality than newer stuff as these days its all about minimalistic design and it kills me.
Trouble with old stuff, is old electronics in general. it starts showing its age. Caps leaking, electromigration in the high speed high current semiconductors, etc. Kinda like a vehicle, and its 200K+ miles service. it needs all things rubber replaced at that point usually.
Prime example is I have a very old Phoenix Gold amp that leaked its capacitor guts into the PCB and its causing tons of parasitic issues related to that with keeping the SMPS running or even to start up properly. It seems once that happens, its terminal. Unless you can get all the electrolyte out of the PCB including the inner layers. Not to mention it reeks of dead fish, even after ultrasonic cleaning.
Anyways, I digress... Yes this is a topic for another thread at another time.
Trouble with old stuff, is old electronics in general. it starts showing its age. Caps leaking, electromigration in the high speed high current semiconductors, etc. Kinda like a vehicle, and its 200K+ miles service. it needs all things rubber replaced at that point usually.
Prime example is I have a very old Phoenix Gold amp that leaked its capacitor guts into the PCB and its causing tons of parasitic issues related to that with keeping the SMPS running or even to start up properly. It seems once that happens, its terminal. Unless you can get all the electrolyte out of the PCB including the inner layers. Not to mention it reeks of dead fish, even after ultrasonic cleaning.
Anyways, I digress... Yes this is a topic for another thread at another time.
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