Sorry I had to wait until thread was aproved.
The c511 was damaged and I replaced it (radio shack .1 uf 50v 🙁 ) also noticed the fuses were blown. but replacing them did nothing as they blew again. What and how should I proceed?
Thanks
The c511 was damaged and I replaced it (radio shack .1 uf 50v 🙁 ) also noticed the fuses were blown. but replacing them did nothing as they blew again. What and how should I proceed?
Thanks
Also I'm in need to learn to repair. so I want to to this DIY way!
I measured the most of the diodes, seem ok (620-640ohms one, way none the other)
How do I measure the transistors as they seem to be the problem?
I measured the most of the diodes, seem ok (620-640ohms one, way none the other)
How do I measure the transistors as they seem to be the problem?
That's the PSU you have posted.... maybe it's a bit early in the morning lol... it's a bit odd.
Which fuses are blowing ?
Do they blow with no speakers connected ?
It looks like the amp runs on a high stabilised supply with a lower higher current supply to "take over" if the output increases beyond a certain point.
Most amp faults see the output transistors fail... either as "just" that or with other damage.
You need to put a mains filament bulb of say 100 watts in series with the incoming supply to allow you to work on it non destructively.
Which fuses are blowing ?
Do they blow with no speakers connected ?
It looks like the amp runs on a high stabilised supply with a lower higher current supply to "take over" if the output increases beyond a certain point.
Most amp faults see the output transistors fail... either as "just" that or with other damage.
You need to put a mains filament bulb of say 100 watts in series with the incoming supply to allow you to work on it non destructively.
There is a switch that allows for 4 ohm or 8 ohm operation. All fuses where blown, as I tried changing the position while debuggin.
How ever after reolacing the c501 and fuses, I left the switch on the 8 ohm position and only f503 and 504 blew.
How ever after reolacing the c501 and fuses, I left the switch on the 8 ohm position and only f503 and 504 blew.
I'm trying to add a better shematic view with no luck. also I have to wait for approval on postings. is there a post limit to be able to post inmediatly or something?
Where do I connect the 100 watt bulb ?
the speakers where installed when this happened.
Where do I connect the 100 watt bulb ?
the speakers where installed when this happened.
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Ok here are the ones that are probable cause. Q501- 2sa1015y,
Q503- 2sa905y, Q505 -2sb363
If I where to replace them, and want to improve quality of sound.
Where and what brand to buy?
Thanks
Q503- 2sa905y, Q505 -2sb363
If I where to replace them, and want to improve quality of sound.
Where and what brand to buy?
Thanks
About 6 posts I think 🙂
If it's blowing fuses it's 99% certain to be one or more of the output transistors that are short circuit. Measure them ! That's Q415/6/7 and 8
None of the transistors in the PSU would cause it to blow fuses.
The 100 watt bulb goes in series with the mains to the amp to limit current. Instaead of fuses blowing the bulb lights.
Don't have any load connected to the speaker outputs during testing.
Check those output transistors first, middle leg to the emmiter and see if they read short circuit.
If it's blowing fuses it's 99% certain to be one or more of the output transistors that are short circuit. Measure them ! That's Q415/6/7 and 8
None of the transistors in the PSU would cause it to blow fuses.
The 100 watt bulb goes in series with the mains to the amp to limit current. Instaead of fuses blowing the bulb lights.
Don't have any load connected to the speaker outputs during testing.
Check those output transistors first, middle leg to the emmiter and see if they read short circuit.
I gave up on this project and will be replacing the amp with a Class D audio (brand) amplifier.
Thanks for your help though. I was a bit limited in time with this project and tried to use it as a learning tool. Still need to learn to repair equipment (mostly audio) Any input on how I can start to learn to repair will be welcomed.
I also started to enjoy the hobbies of listening to audio and modifying the equipment for better performance, and thats what Im doing for now.
Thanks for your help though. I was a bit limited in time with this project and tried to use it as a learning tool. Still need to learn to repair equipment (mostly audio) Any input on how I can start to learn to repair will be welcomed.
I also started to enjoy the hobbies of listening to audio and modifying the equipment for better performance, and thats what Im doing for now.
Reading up on theory about how things are supposed to work will help, but the only real way to teach yourself is to do it.
And blow things up again.
And burn your fingers.
And curse.
Cliff
By reading mostly and trying things out, and building things.
You must understand semiconductor theory, and how that translates into practical measurements on equipment.
There's no quick way... if it's a subject you are interested in, you will learn the basics quickly... and thereafter you never stop learning.
LOL yeah it burns hot like !@#$
Thanks for the advice.
My next project is building a Class D Audio amplifier (ClassDAudio brand)
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