Marantz 2215B Repair Part 2 - Bulbs Replacement & Bias Issue
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- Опубликовано: 16 сен 2024
- There were some pre-existing damages inside this unit. So even after I completed the initial repair, I still can't adjust the bias on the right channel. In this video I am sharing the repair process and hope it will be useful to other DIY fans if they have the same problem in their units. I welcome your suggestions and comments regarding this repair video.
Really helpful video, i really appreciate the details given here.
I am working on a 2215B and getting high distortion in left channel at volume at 15-25%. Am getting zero bias on left channel as well.
This distorted audio persists even while using a headphone as well on the left channel.
All voltages match to right channel with right channel bias at 9mv. Right channel sounds perfect.
Thanks for the comments. Sorry to hear that you have a distortion issue on your 2215B. I suggest to check the power and driver transistors if you have distortion and can't adjust the bias. Please send your inquiries to my email if further help is needed.
@@VintageAudioFan Thanks for the quick reply, I sent you an email.
Well done! Thanks for showing, these videos are very helpful
Great job, great final jazz music test. Could you tell me where to find bulb led like yours please ?
Thank you for your comments. You can buy LED lamps at eBay website. Just type in "Marantz LED lamps", there are many vendors available.
Great Repair
Hello! Do you know what can happen if I turn the receiver on without having speaker set turned off beforehand? I mean, can this damage the speakers? I think that the volume was a little bit turned on, but not much.
The circuit of Marantz 2215B is an OTL design. Usually OTL amplifiers use an output capacitor to eliminate DC output which will help protecting the speakers. So it should be fine with the speaker connected to the unit when turning on the receiver. It is always a good practice starting with low volume to power on the amplifier.
@@VintageAudioFan I accidentally turned it on without realizing speakers were switched on, but volume was fortunately relatively low. But I figure it wasn't critical because the unit outputs 15W/ch and my speakers are able to withstand 40W. I don't think that blast was anywhere near 15W.
How do you know if the Reciever needs to be re-bias?
When unit has been used for a long period of time, the compartments (i.e. transistors and capacitors) may be aged or degraded. They can cause problems in the amplifier circuitry. The value of DC balance/bias of amplifier may become off based on the OEM's specifications. In that case, it may kick on the speaker protection mode or cause the distortion for the sound outputs. So it is good idea to check Dc balance and bias to ensure amplifier is in proper working condition.