Emax

Did you check continuity on the traces carrying the power to the switches etc?

To: emax@yahoogroups.com
From: nikkinloch@...
Date: Sat, 5 Nov 2011 12:36:07 +0000
Subject: [emax] Re: Most front panel buttons don't work - Emax 1 Rack HD














 



  


    
      
      
      Thanks mate.



Just did a voltage check on the switches, interesting results.



There is no voltage at either side of any of the switches that are not working.



The only switches that have voltage, and therefore are working (albeit not correctly), are:



0, 9, 7

Off / No

Enter

Play

Record

Preset Management



This leads back to no power at Diodes 5 / 6 / 7, but diode 8 has power.



The schematic  (PDF service manual, page 48) shows these coming from IC12, which is a CD4028BE. This chip then goes to the Scanner CPU IC7, which is an IM368-1 BA / R1125-11.



I am not sure how to test from here on. I have the datasheet for CD4028BE, but I'm not 100% sure how to read it to confirm operation of this chip. However, I have made a guess and it seems the inputs to this chip are correct, so at a large guess I suspect this chip to have failed. I hope so anyway, because it is still available. I'm going to try to source one and swap it out.



Any further help, advice, prayers, raindances, or evocations appreciated!



--- In emax@...m, "emax_dx5" <cadena100rb@...> wrote:

>

> Hello.

> When The R1125 fails, usually all the key functions (Both keyboard and buttons/Sliders) stop working. This chip scans all traffic between interface and cpu. It could be damaged but mine (and some other cases I knew) were as described before.

> Best..

> 

> 

> 

> 

> --- In emax@yahoogroups.com, "mcnik_k" <nikkinloch@> wrote:

> >

> > Hi,

> > 

> > It is a rack.

> > 

> > Mobo EMAX CPU PCB PC333 BOARD REV A

> > 

> > Seems like it is possible to get the CMOS chips still http://parts.digikey.com/1/parts/515947-ic-octal-d-type-f-f-hs-20-dip-cd74hct273e.html

> > 

> > Will reply regarding your services off list.

> > 

> > Many thanks!

>






    
     

    
    






  






 		 	   		  

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