Hello,
I am going to throw this out on the forum for any assistance would be greatly appreciated. I have a Mark Levinson 23.5 amp. Recently my left channel has become fuzzy /distorted at low and higher volume. It's more noticeable at lower volume or passages tho. I checked all of the obvious including swapping speaker cables and inputs etc. The problem is definitely in the amp. I also noticed after playing the amp for a while, the heatsinks on the right side of the amp feel warm, normal warm while the heatsinks on the left side is cooler. Don't get me wrong, they're warm but not as warm as the right side and as they usually feel. The output on both channels seems ok. Don't think I've lost any power. Can anyone give me some information where to start. I am pretty handy but am not a technician. I have done some electronic repairs in the past. I know how to use multimeters and also still have a Simpson 260 if I need to break it out. PLEASE, any help would be greatly appreciated. Lastly, once I get his thing working, would it be wise to recap the amp? Thank you in advance for any help you guys can offer.
I am going to throw this out on the forum for any assistance would be greatly appreciated. I have a Mark Levinson 23.5 amp. Recently my left channel has become fuzzy /distorted at low and higher volume. It's more noticeable at lower volume or passages tho. I checked all of the obvious including swapping speaker cables and inputs etc. The problem is definitely in the amp. I also noticed after playing the amp for a while, the heatsinks on the right side of the amp feel warm, normal warm while the heatsinks on the left side is cooler. Don't get me wrong, they're warm but not as warm as the right side and as they usually feel. The output on both channels seems ok. Don't think I've lost any power. Can anyone give me some information where to start. I am pretty handy but am not a technician. I have done some electronic repairs in the past. I know how to use multimeters and also still have a Simpson 260 if I need to break it out. PLEASE, any help would be greatly appreciated. Lastly, once I get his thing working, would it be wise to recap the amp? Thank you in advance for any help you guys can offer.
Mark Levinson 23.5 amp
Hi; I own two 23.5 amps. My suggestion is to find an authorized Mark Levinson Service center near you and take it to them. Not dissing your electronic skills, but the 23.5 is a serious pain in the behind to work on. I imagine without looking at it, that some pre-drivers and output drivers may be bad. However, you just don't know.
There is a 23.5 schematic on line you can download.
Also, regarding the power supply caps and other electrolytic caps, visually inspect the caps for leakage, bulging, etc. Normal signs they are failing. If you don't see anything, I wouldn't replace them at this time.
Again, the authorized service center can do that for you also.
The one near me in Los Angeles, is George Meyer audio. They do pretty good work and they repaired one of my 23.5's, and upgraded both with Mark Levinson recommended upgrades and they recapped them also.
If you have the service manual with the schematic showing the proper voltages at certain points, you can diagnose the problem fairly well.
But, the 23.5 is pain. It has two large circuit boards that are connected via long solid leads. You have to unsolder these to get to the driver transistors.
Make sure you properly discharge the capacitors before you move the heat sinks out of the way. It is so closely packed, that it is very easy to short these, and you would cause some major problems if you do.
enjoy
Hi; I own two 23.5 amps. My suggestion is to find an authorized Mark Levinson Service center near you and take it to them. Not dissing your electronic skills, but the 23.5 is a serious pain in the behind to work on. I imagine without looking at it, that some pre-drivers and output drivers may be bad. However, you just don't know.
There is a 23.5 schematic on line you can download.
Also, regarding the power supply caps and other electrolytic caps, visually inspect the caps for leakage, bulging, etc. Normal signs they are failing. If you don't see anything, I wouldn't replace them at this time.
Again, the authorized service center can do that for you also.
The one near me in Los Angeles, is George Meyer audio. They do pretty good work and they repaired one of my 23.5's, and upgraded both with Mark Levinson recommended upgrades and they recapped them also.
If you have the service manual with the schematic showing the proper voltages at certain points, you can diagnose the problem fairly well.
But, the 23.5 is pain. It has two large circuit boards that are connected via long solid leads. You have to unsolder these to get to the driver transistors.
Make sure you properly discharge the capacitors before you move the heat sinks out of the way. It is so closely packed, that it is very easy to short these, and you would cause some major problems if you do.
enjoy
Thank every one of you for your suggestions and cautions. I really don't want to ship the amp if I don't have to. That was why I was attempting to poke around in it myself. I think I will open it up on the weekend and nosey around a bit. maybe then what you guys are referring to will probably make more sense. Does anybody have the service manual you'd be willing to share?
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