Vintage Synth Repair

Eproms do not need a battery to hold data..it's
permanent(sort of).

Im not being funny but a lot of your questions are
answerable with a quick google search. for instance:

http://en.wikipedia.org/wiki/EPROM

You should do that before asking on lists as you will
gain a much better understanding reading some good
articles.

Also without some basic understanding of how synths
and basic digital electronics work..IE old CPU's rom ,
ram busses...you are going to be pretty much stabbing
in the dark here unless you are lucky.

I suggest spending some time reading up and
researching properly..I honestly don't mean any of
this in a patronising way. I just think it will help
you to move forward and achieve your goal.

I believe there are some very good books out there on
these subjects.

Phil.

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

> On Brd 3 there are three EPROMs with the Z80 CPU.
> The first says: 0 TEN 5.0, second says: 1 TEN 5.0,
> third says: 2 TEN 5.0 on their stickers. 
> 
> On Brd 9 there is one EPROM with the Z80 CPU. The
> sticker on it is not too legible what I do see is:
> SEQ (that part is clear) below it say C1 or C.1 or I
> was thinking maybe 2.1( if upper half of 2 was
> missing). 
> 
> Both Z80s on pin 6 CLK have 2.5MHz clock at about 4v
> p-p. and 5v dc on pin 11. Does the EPROM lose all
> programming if battery dies? If so how do you
> reload? Will keyboard not boot without EPROM
> program. My friend today is bringing me a Z80 CPU in
> so I can swap out.
> 
> 
> 
>   ----- Original Message ----- 
>   From: thirteentech 
>   To: vintagesynthrepair@yahoogroups.com 
>   Sent: Monday, April 28, 2008 7:47 AM
>   Subject: [vintagesynthrepair] Re: Prophet 10
> repair (was Hi from a new member).
> 
> 
>   What is written on the stickers on the EPROMS?
> 
>   --- In vintagesynthrepair@yahoogroups.com, "Frank
> Simon" <fsimon001@...> wrote:
>   >
>   > I don't know. How do I find this out.
>   > ----- Original Message ----- 
>   > From: Stephen Jones 
>   > To: vintagesynthrepair@yahoogroups.com 
>   > Sent: Monday, April 28, 2008 12:14 AM
>   > Subject: Re: [vintagesynthrepair] Re: Prophet 10
> repair (was Hi from a new member).
>   > 
>   > 
>   > Which Rev. Processor board do you have? All the
> Rev.
>   > 3.1 and 3.2 Prophet 5's have a built in memory
> test,
>   > and latest software versions also have a basic
> CPU
>   > test. Which software version do you have?
>   > 
>   > --- Frank Simon <fsimon001@...> wrote:
>   > 
>   > > Steve,
>   > > The TUNE LED does not come on. Since I am four
>   > > CEM3310s short, should certain slots be
> populated
>   > > just to get boot up? All the supplies are up.
> I am
>   > > suspicious of PCB9 due to the 12v applied and
> you
>   > > mentioned EQ board. There are a couple IC's
> that are
>   > > warm on the EQ board but not so hot I can't
> keep my
>   > > finger on it. Can you offer a couple key
>   > > troubleshooting spots for measurements to help
> me
>   > > isolate this? I'm assuming I have no way to
> bless
>   > > the Processor. All I have is an Oscope,
> function
>   > > generator, and multimeter.
>   > > 
>   > > 
>   > > ----- Original Message ----- 
>   > > From: thirteentech 
>   > > To: vintagesynthrepair@yahoogroups.com 
>   > > Sent: Monday, April 21, 2008 12:21 AM
>   > > Subject: [vintagesynthrepair] Re: Prophet 10
>   > > repair (was Hi from a new member).
>   > > 
>   > > 
>   > > When you turn the machine on the front panel
>   > > should be dark with the exception of the 
>   > > [TUNE] switch. The machine boots into it's
>   > > autotune mode and suppresses all of the front 
>   > > panel lights and controls while it does so. it
>   > > should take 8-10 seconds if the machine is 
>   > > functional, longer if voices are way out of
>   > > calibration.
>   > > 
>   > > Does the TUNE button LED come on when you
> power
>   > > up?
>   > > 
>   > > --- In vintagesynthrepair@yahoogroups.com,
> "Frank
>   > > Simon" <fsimon001@> wrote:
>   > > >
>   > > > Steve,
>   > > > I have all power supplies in order. There is
>   > > power to all boards. When I turn it on 
>   > > shouldn't it boot up and LED's cycle on or
> blink
>   > > or even be switchable? The panel is dead. 
>   > > Does this sound like processor to you?
>   > > > 
>   > > > ----- Original Message ----- 
>   > > > From: thirteentech 
>   > > > To: vintagesynthrepair@yahoogroups.com 
>   > > > Sent: Saturday, April 19, 2008 1:07 AM
>   > > > Subject: [vintagesynthrepair] Re: Prophet 10
>   > > repair (was Hi from a new member).
>   > > > 
>   > > > 
>   > > > Each of the 5 voices on each voice board has
> two
>   > > CEM3310 envelope generators. One 
>   > > > controls the volume envelope of the voice,
> and
>   > > the other controls the filter cutoff of 
>   > > the 
>   > > > voice if you bring up the filter envelope
>   > > modulation control. If the 3310's in the
> filter 
>   > > > control line are faulty it should only
> manifest
>   > > when you turn on the filter envelope 
>   > > > modulation. If this is off then the voice
> should
>   > > sound if the VCF cutoff pot is set open. 
>   > > If 
>   > > > you have bad 3310's in the VCA envelpoe
>   > > position, the voice won't sound.
>   > > > 
>   > > > I am assuming that your P10 has Rev 3.x
> Prophet
>   > > 5 voice boards in it, because in the 
>   > > > Sequential System Technical manual which
> covers
>   > > all Prophets from Rev 3.0-3.2, the 
>   > > > Prophet 10 and the Poly Sequencer, they all
> use
>   > > the same basic voice board. So for 
>   > > > instance, in Voice 1 of the voice board,
> U412 is
>   > > the amplifier envelope generator, and 
>   > > > U417 is the filter envelope generator.
>   > > > 
>   > > > --- In vintagesynthrepair@yahoogroups.com,
>   > > "Frank Simon" <fsimon001@> wrote:
>   > > > >
>   > > > > Steve,
>   > > > > I am pleased to know there is a technique
> to
>   > > troube this with the bad ICs. I hope to 
>   > > get 
>   > > > to that point soon. If I remember there were
> no
>   > > LEDs on control panel lit when turned 
>   > > on. 
>   > > > Is there a local spot that isolates that
>   > > symptom? I haven't removed the top boards yet.
> 
>   > > > Hopefully I can handle that. 
>   > > > > 
>   > > > > I guess I am confused on VCA and VCF
> envelope
>   > > positions. Can you give me a 
>   > > > explanation of how to determine which state
> the
>   > > IC is in.
>   > > > > Frank
>   > > > > 
>   > > > > 
>   > > > > 
>   > > > > 
>   > > > > ----- Original Message ----- 
>   > > > > From: thirteentech 
>   > > > > To: vintagesynthrepair@yahoogroups.com 
>   > > > > Sent: Friday, April 18, 2008 6:04 PM
>   > > > > Subject: [vintagesynthrepair] Prophet 10
>   > > repair (was Hi from a new member).
>   > > > > 
>   > > > > 
>   > > > > Well, if you have metered all of the power
>   > > supply rails in the machine, and are 
>   > > satisfied 
>   > > > > that they are all in spec, then go ahead
> and
>   > > put the voice boards back in. Remove the 
>   > > > > known bad 3310's, and if any were in VCA
>   > > ENVELOPE positions, replace them with 
>   > > > 3310's 
>   > > > > from VCF ENVELOPE positions. This will
> allow
>   > > you to set up a patch with the VCF 
>   > > > envelopes 
>   > > > > control turned off and still have all of
> the
>   > > voices audible so that you can hear is all 
>   > > the 
> 
=== message truncated ===



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