[sdiy] DX7 Memory Problem

[gregory zifcak]

Thanks for the tips!

________________________________
> Date: Mon, 20 Aug 2012 16:55:53 +0100 
> Subject: Re: [sdiy] DX7 Memory Problem 
> From: jason at tribbeck.com 
> To: neil.johnson97 at ntlworld.com 
> CC: zifcak at hotmail.com; synth-diy at dropmix.xs4all.nl 
>  
> Hi, 
>  
> Turned pin sockets :) 
>  
> On 20 August 2012 14:56, Neil Johnson  
> <neil.johnson97 at ntlworld.com<mailto:neil.johnson97 at ntlworld.com>>  
> wrote: 
> Hi, 
>  
> The CY7C185-20PXC looks compatible.  Available from Farnell too: 
>  
> http://uk.farnell.com/cypress-semiconductor/cy7c185-20pxc/ic-sram-64k-8kx8-20ns-dip28/dp/1688740 
>  
> The address lines are in a different order, but that won't matter. 
>  
> If the chips truly are toast, cut them off the board first, then 
> desolder the remaining bits of pin.  Much easier than trying to remove 
> a 28-pin DIP - you want to keep the PCB intact. 
>  
> And then fit sockets :) 
>  
> Cheers 
> Neil 
>  
> On 20 August 2012 14:15, gregory zifcak  
> <zifcak at hotmail.com<mailto:zifcak at hotmail.com>> wrote: 
> > 
> > Thanks for the tip, unfortunately they are not socketed. 
> > 
> > ---------------------------------------- 
> >> Date: Sun, 19 Aug 2012 00:20:39 -0700 
> >> From: dmarv at dop.com<mailto:dmarv at dop.com> 
> >> To: synth-diy at dropmix.xs4all.nl<mailto:synth-diy at dropmix.xs4all.nl> 
> >> Subject: Re: [sdiy] DX7 Memory Problem 
> >> 
> >> On 8/18/2012 11:39 PM, gregory zifcak wrote: 
> >>> Cool, thanks for the info. Yeah I have memory protect off. I found  
> the self-test procedure and it fails at the RAM check. I will check the  
> chip enable lines as you said; I'm guessing one or both of the RAM  
> chips died. The chips are 8k, part number TC5564PL-15. That would be  
> great if you have some spares. 
> >>> Greg 
> >>> 
> >>> 
> >> Greg, 
> >> If the RAM is in a socket, try reseating it before replacement. I'm in 
> >> Southern California and have seen lots of problems from corrosion on 
> >> sockets. 
> >> 
> >> Dale 
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