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Author Topic: TOA M-243 Line Mixer Circuit Diagram?  (Read 3496 times)

Mike Karseboom

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TOA M-243 Line Mixer Circuit Diagram?
« on: December 13, 2013, 03:36:21 PM »

I am trying to locate a service manual or circuit diagram for the TOA M-243 Line Mixer.  This mixer has an ducking feature that works well but the background music ramps back up faster than  I would like.  So if you pause even slightly during an announcement the BGM cuts back in before you get a chance to continue with the announcement.   The is no adjustment for this externally or internally. 


I want to explore the feasibility of lengthening the time it takes  the background music to ramp back up by possibly changing some component on the PCB.  It is mostly discreet components but there are a few IC's.


Any help would  be appreciated.
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John Roberts {JR}

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Re: TOA M-243 Line Mixer Circuit Diagram?
« Reply #1 on: December 13, 2013, 04:25:40 PM »

Just making a WAG there is probably a capacitor involved that sets the duck time. Simply add a capacitor in parallel to make the capacitance larger should linearly increase the duck recovery delay proportionately.

JR
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Mike Karseboom

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Re: TOA M-243 Line Mixer Circuit Diagram?
« Reply #2 on: December 13, 2013, 05:16:41 PM »

Just making a WAG there is probably a capacitor involved that sets the duck time. Simply add a capacitor in parallel to make the capacitance larger should linearly increase the duck recovery delay proportionately.

JR


That is sort of what I was speculating.  Not that I would be able to figure out the correct item(s) to replace or the correct values.    But if I can get a schematic then at least I could  get some one to make the change or perhaps tell me and I could do it.  The PCB's actually look pretty easy to work on.  Components on one side and traces on the other.


I am in a remote area and just sending the thing out for someone to investigate and possibly find a solution would probably be more costly than it is worth to me.  It is possible that the "mute block" is part of an IC  which would make it a tough fix.  At least with the circuit diagram I could assess the feasibility.


Any idea where I might find this?  My web searching so far yields only block diagrams. 
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--Mike
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John Roberts {JR}

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Re: TOA M-243 Line Mixer Circuit Diagram?
« Reply #3 on: December 13, 2013, 06:18:37 PM »

It is not likely that the delay cap would ever be inside an IC. So relatively straightforward DIY self help.  While I do not know for a fact how they do it. TOA (all) instal products are pretty low tech.

Have you considered asking TOA?

JR
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Mike Karseboom

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Re: TOA M-243 Line Mixer Circuit Diagram?
« Reply #4 on: December 13, 2013, 06:49:33 PM »



Have you considered asking TOA?

JR


Duhh... I just called them and have a PDF schematic in hand.  I guess I am so used to dealing with the MI oriented vendors like Mackie, QSC, etc. where it is very time consuming to get anything like this.  Now to try and figure it out.


Thanks for the suggestion.
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levent demir

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Re: TOA M-243 Line Mixer Circuit Diagram?
« Reply #5 on: August 01, 2014, 05:30:48 PM »

I tried to find the service manual but I found this: http://www.toaelectronics.com/products/mixers/brochures/m-243.pdf.
As you are looking for the circuit diagram and it is available in this pdf. Hopefully it will be beneficial for you.

Mac Kerr

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« Reply #6 on: August 01, 2014, 09:04:43 PM »

Hopefully it will be beneficial for you.

Please go to your profile and change the "Name" field to your real first and last name as required by the posting rules displayed in the header at the top of the section, and in the Site Rules and Suggestions in the Forum Announcements section, and on the registration page when you registered.

Mac
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« Reply #6 on: August 01, 2014, 09:04:43 PM »


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