Vintage Synth Repair

Yeh...Scratchpad can use standard 2114. NV ram = Non
volatile IE User patch memory..which is obviously
battery backed-upped and so uses 5114/6514 CMOS ram
due to it's low current drain. 

Therefore the 2114 will probably drain the memory
battery very quickly due to the higher current drain
of  NMOS technology.

2114 is not compatible with 5114 in this situation,
sure it will get it to work in the short term..I've
done it myself popped in a 2114 to check
circuits...5114 5514 6514 D444C are all crosses of
each other. They are all hard to find too. 2114 is
easy to get.

If anyone knows better you are welcome to correct me
of course!

Phil.



--- Frank Simon <fsimon001@...> wrote:

> I like to hear these details. Off the decoder is
> NV1,NV2, and Scratch RAM. On my schematic my
> scratchpad RAM are two 2114s. The part that failed
> was as you know a D444C and was part of NV1.  All of
> these are 1K x 4bit. The NV memory on my schematic
> say 6514. But at least putting the 2114 in showed me
> the failed part. If you think the 6514 is more
> compatible with 5114 I'll replace it. Do you know
> details of 6514.
> 
>   
>   ----- Original Message ----- 
>   From: Philip 
>   To: vintagesynthrepair@yahoogroups.com 
>   Sent: Friday, June 06, 2008 9:43 PM
>   Subject: Re: [vintagesynthrepair] Re: Prophet 10
> dead
> 
> 
>   Well you should have used a 5114 not a 2114, that
> I'm
>   pretty sure of, will cause you problems.
> 
>   A 2114 is not a cmos device, it is an
> nmos..therefore
>   they use different currents..a D444 is pretty fast
> too
>   12ns or something.
> 
>   For instance patch memory: a 5114 connected to a
> 3v
>   lithium battery will last years..but with 2114 it
> will
>   last a few days.
> 
>   Perhaps others with better knowledge than me on
> this
>   subject can explain further?
> 
>   Phil.
> 
>   --- Frank Simon <fsimon001@...> wrote:
> 
>   > I found an Motorola MCM2114P45 from a ebay
> seller
>   > for $3. I was hesitant because it was their
> slowest
>   > access time part at 450nS. I don't know what the
>   > D444C access time spec is. I figured it was
> around
>   > 200nS but hopefully the 450 is ok.
>   > 
>   > 
>   > ----- Original Message ----- 
>   > From: Philip 
>   > To: vintagesynthrepair@yahoogroups.com 
>   > Sent: Friday, June 06, 2008 8:21 AM
>   > Subject: Re: [vintagesynthrepair] Re: Prophet 10
>   > dead
>   > 
>   > 
>   > Excellent news, well done..so did you use the
> Ram
>   > I
>   > suggested? Or did you find a 444?
>   > 
>   > Thanks, Phil.
>   > 
>   > --- fsimon100 <fsimon001@...> wrote:
>   > 
>   > > I truly had a great day. I replaced a 1Kx4 RAM
>   > and
>   > > resolved my 
>   > > computer problem on my P10. Now all LEDs light
>   > up
>   > > and the unit 
>   > > behaves somewhat functional. Upon turn on the
>   > unit
>   > > goes to tune cycle 
>   > > then all LEDs light up and entire panel is
>   > > functional. Still no sound 
>   > > but this is a great milestone. Two problems I
>   > see
>   > > are sequential 
>   > > board is dead which I think I'm on top of.
> This
>   > is
>   > > PCB9 which I over 
>   > > voltaged when I put the 12V regulator in
> instead
>   > of
>   > > 5V (due to poor 
>   > > documentation this is an option for tape or
>   > wafer
>   > > drive). I think 
>   > > this will be easy to fix but I was hoping to
>   > help on
>   > > one clue. There 
>   > > is a window showing voices 1 thru 5 and below
> 6
>   > thru
>   > > 10. The top 1 
>   > > thru 5 show 1,3, and 4 LEDs on continously
> never
>   > > changing. The bottom 
>   > > 6 thru 10 change as I hit the keys as if it is
>   > > responding however LED 
>   > > 7 never comes on. Can someone offer advice. I
>   > have 4
>   > > CEM3310s out on 
>   > > the top voice board. It is to my understanding
> I
>   > may
>   > > get a noise out 
>   > > if configured right to see functionality
> before
>   > I
>   > > buy expensive chips.
>   > > 
>   > > Sorry long but I am very happy to be at this
>   > status.
>   > > Can sequencer 
>   > > shut down operation. Was curious, should I get
>   > sound
>   > > without 
>   > > sequencer.
>   > > 
>   > > 
>   > > 
>   > > --- In vintagesynthrepair@yahoogroups.com,
>   > "Frank
>   > > Simon" 
>   > > <fsimon001@...> wrote:
>   > > >
>   > > > I did find a chip pulling down DB4 on U311
> it
>   > is a
>   > > 6514 4K CMOS 
>   > > RAM. Thank god for IC sockets. The only
> problem
>   > I'm
>   > > a little confused 
>   > > on a cross for it. It appears obsolete. It is
>   > called
>   > > D444C on the 
>   > > chip and 6514 on schematic. Can anyone offer
>   > advice
>   > > on a cross.
>   > > > ----- Original Message ----- 
>   > > > From: fsimon100 
>   > > > To: vintagesynthrepair@yahoogroups.com 
>   > > > Sent: Friday, May 30, 2008 8:58 AM
>   > > > Subject: [vintagesynthrepair] Prophet 10
> dead
>   > > > 
>   > > > 
>   > > > Was curiouse if anyone can offer help. I
>   > bought
>   > > a dead P10 no 
>   > > lights 
>   > > > or anything. The processor is good. I put
>   > logic
>   > > analyzer on 
>   > > decoder 
>   > > > output and see ROM1 (Y0) and RAM (Y5)(which
> I
>   > > believe is the 
>   > > scratch 
>   > > > pad memory)active at start up. All address
>   > buses
>   > > and Data buses 
>   > > are 
>   > > > active. I am not certain the algorithm. A
> flow
>   > > chart would be 
>   > > nice or 
>   > > > some help with what I should see at some
>   > > critical points. I am 
>   > > > wondering if there is a chance the ROMs lost
>   > > programming and how 
>   > > would 
>   > > > I know. Even if they did shouldn't lights
>   > and/or
>   > > display come on. 
>   > > And 
>   > > > yes the power supplies are good.
>   > > >
>   > > 
>   > > 
>   > > 
>   > 
>   > 
>   >
>  
>
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>   > 
>   > 
> 
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