开云体育

Hi Steve, you can count me in as wanting a production board!


--
Amanda
SynthSights! "it's not about the gear"
Come join us! Info. at: www.synthsights.net
*_
|_) _ _||\/| _ _ ._ www.cikira.com
| \(/_(_|| |(_)(_)| | ~~~~~~ www.redmoon-music.com

My Xpander was working fine (I bought it new in the late 80's).
I decided to put in a new battery (I was in the process of
changing the batteries on a bunch of my gear) and did so.
The operation seemed to be a success since I was able to load the
factory patches and they stay in memory over a power cycle.
The problem is that the VCO tests/tunings all fail (every other test
passes).
All the VCOs are way out of tune or almost silent. Any suggestions
would be greatly appreciated. I have gone through the reset sequence
with no luck.

Thanks,

Hi,

I'm new here, so perhaps I should introduce myself. My name is Steve
Lenham and I run a small design consultancy in south-eastern England,
an increasing part of which involves working on classic synths and
related equipment.

I recently restored an Xpander and, amongst other things, its owner
asked me if anything could be done about the failing vacuum-
fluorescent displays. As a result, I designed and produced a
replacement display board fitted with three Itron DN4015 displays and
wonder whether it might be of interest to others here.

Full details can be found on my website:

www.bendentech.co.uk/sound/obvfd.html

Unfortunately it would appear that Japanese-made synths use a single-
piece display/panel PCB, so aren't compatible with this upgrade. Can
anyone tell me what proportion of units were made in Japan?

Initially I am looking for a small number of technically-competent
beta testers for the upgrade to confirm its reliability. They will
get a nice discount in return for their feedback. UK-based testers
would be preferred for logistical reasons, and I would particularly
welcome Matrix-12 owners since I would like to establish any relevant
differences.

However, do please also let me know if you would be interested in a
production board - I'd like to know whether this is worth pursuing!

Best regards,

Steve Lenham
Benden Sound Technology
bst@...

Karl,

Thank you for the tips, at least I can hear the quantize effect. I
reached my geek quest ;)

Hi,

I had to go through my patches to find some patchs using quatize.
It seems AFAIK the quantize function is most useful when modulating
the frequency of a VCO. As you point out it is hardly noticable on
other modulations.
You can quantize the lag modulations going to the VCOs repete many
times to get a large range. This gives a glisando sound Tomita used
on Planets. " Turn the regular lag off in the main VCO page"
I have also found it useful to quatize square or tri wave LFOs
modulating the VCO frequency. You can get a stepped series of notes
in halfsteps.
If you feel ambitious try several LFOs all set to the same frequency.
Then adjust the re-trigger different for each LFO. This creates a
programmable arpeggio.
I remember using it once on a modulation of an LFO rate to sync
things together. But I can't find this patch.

Hope this helps

Karl









--- In xpantastic@..., "baumont987" <geebeex@...> wrote:

I found the differences between these messages. It's only about how

to

activate/desactivate the quantize:

- action=06h "toggle" simply toggles the actual quantize. If it's

ON,

it will go OFF and vice-versa.
- action=05h is set quantize ON or set OFF. Is that simple :)

My question was more about what it does to the *sound*. I tried many
settings (just a VC0, and set quantize to a mod source for VC0 freq,
VCF freq and so on). I do not hear any difference between quantize

ON

or OFF).

This was my question because I'm currently developping a real-time
control/programming software for the XPander. My program do send the
right SysEx message, but I wondered there where no differences in

the

sound itself.

I looked into my SysEx presets and I did not found any preset with a
quantize modulation. strange.

Looks like this option is never used or does nothing at all (?)

/Greg

--- In xpantastic@..., "Tony Cappellini" <cappy2112@>
wrote:

In the MIDI implementation, it's possible to enable/disable the
quantize thru a "Modulation edit follows" SysEx message (with
action=05h which is "set quantize on/off"). The same message

with

action=06h is "toggle quantize N/A".
Does anybody knows what the difference is between this two

messages ?

As far as I know, it's only possible to enable/disable the

quantize

from the XPander panel.

How about sending one of those messages via midi, save the patches
(before/after the messages), to see which bit(s) are set or

cleared

(if any).
Repeat with the other message.

I found the differences between these messages. It's only about how to
activate/desactivate the quantize:

- action=06h "toggle" simply toggles the actual quantize. If it's ON,
it will go OFF and vice-versa.
- action=05h is set quantize ON or set OFF. Is that simple :)

My question was more about what it does to the *sound*. I tried many
settings (just a VC0, and set quantize to a mod source for VC0 freq,
VCF freq and so on). I do not hear any difference between quantize ON
or OFF).

This was my question because I'm currently developping a real-time
control/programming software for the XPander. My program do send the
right SysEx message, but I wondered there where no differences in the
sound itself.

I looked into my SysEx presets and I did not found any preset with a
quantize modulation. strange.

Looks like this option is never used or does nothing at all (?)

/Greg

--- In xpantastic@..., "Tony Cappellini" <cappy2112@...>
wrote:

In the MIDI implementation, it's possible to enable/disable the
quantize thru a "Modulation edit follows" SysEx message (with
action=05h which is "set quantize on/off"). The same message with
action=06h is "toggle quantize N/A".
Does anybody knows what the difference is between this two messages ?
As far as I know, it's only possible to enable/disable the quantize
from the XPander panel.

How about sending one of those messages via midi, save the patches
(before/after the messages), to see which bit(s) are set or cleared
(if any).
Repeat with the other message.

In the MIDI implementation, it's possible to enable/disable the
quantize thru a "Modulation edit follows" SysEx message (with
action=05h which is "set quantize on/off"). The same message with
action=06h is "toggle quantize N/A".
Does anybody knows what the difference is between this two messages ?
As far as I know, it's only possible to enable/disable the quantize
from the XPander panel.

How about sending one of those messages via midi, save the patches
(before/after the messages), to see which bit(s) are set or cleared
(if any).
Repeat with the other message.

Hi,

In the modulation pages of the Xpander, it's possible to set a
quantize option to themodulation. The manual of the Xpander says,
"Quantizing cause semitone steps instead of a smooth change of an
Enveloppe, LFO, Lever or other modulation".

I did set quantize for some modulations of some patches, but I really
can not hear a difference in my sound.
I understand what a "semitone step" is if the modulation destination
is the VCO freq or detune, but what is the meaning for an enveloppe
attack or LFO speed ?

In the MIDI implementation, it's possible to enable/disable the
quantize thru a "Modulation edit follows" SysEx message (with
action=05h which is "set quantize on/off"). The same message with
action=06h is "toggle quantize N/A".
Does anybody knows what the difference is between this two messages ?
As far as I know, it's only possible to enable/disable the quantize
from the XPander panel.

Is a patch with a modulation quantize demo available somewhere ?

Thanks,
/Greg.

Hi Takis,

My original DAC is an MP7614KN, are these two incompatible and
if so why are they mentioned as both able to do the job?

Looking at the data sheets These two parts( MP7614KN and HS3140C) are
the same, and should be interchangable. If you have an output of 4 V
on PIN 6 of the opamp(U815), then the op-amp could be at fault also.

Karl



--- In xpantastic@..., "Karl" <shire03@...> wrote:

Hi Takis,

Does that mean that the DAC is faulty?

Could Be, What happens if you put the old one back in, And check
it's calibration, from pin 6 of U815?

Karl


--- In xpantastic@..., "takisdamaschis"
<takisdamaschis@> wrote:

Hi Karl,
I did the calibration procedure but unfortunately I can't get the

DAC

trimmed down to 0volts!It keeps showing 4v(pin 6)!
Does that mean that the DAC is faulty?

--- In xpantastic@..., "Karl" <shire03@> wrote:

Hi Takis,
On page 34 of the Xpander service manual there is a DAC

calibrtion

procedure. A different chip would need a calibration.
What about the reference voltage?

Karl





--- In xpantastic@..., "takisdamaschis"
<takisdamaschis@> wrote:

Hi Karl,
I just got the new DAC! It's an HS3140C.I installed it
and.....nothing!Every test fails now instead of only some

VCO's!

My original DAC is an MP7614KN, are these two incompatible

and

if so

why are they mentioned as both able to do the job?
Furtermore is there anything else I should have done when I

replaced

the DAC that is not mentioned in the manual?
Thanks,Takis.


--- In xpantastic@..., "Karl" <shire03@> wrote:

Hi Takis,
I measured the D805 in mine: 6.95 Vdc. I notice it's a

diode

in a

transistor package. This is a very accurate reference

diode.

It

should read at least 6.9 Volts. Pin 1 is not used. I

measured

from

The left side of R856 ( just below it) to the middle leg of

the

diode. My schematics identify this as a 6.9 V Zener. If

the

one

in

yours shows a lower voltage than that, maybe this is

causing

the

tuning errors. The diode may not be bad, something maybe

dragging it

down. I would take U815 out (turn Off first), then measure

it

again.

If you can't get 6.9V out of that ref, I would replace it.
BTW about where is the adjustment trimmer pointing?

Karl




--- In xpantastic@..., "takisdamaschis"
<takisdamaschis@> wrote:

Hi Karl,
the voltmeter reads 6.38v!
Takis.

--- In xpantastic@..., "Karl" <shire03@>

wrote:

Hi Takis,

What does the your voltmeter read when you measure the

zener

(D805)?

I keep thinking it's something to do with this circuit.
I am going to open mine up and see what I get.

Karl



--- In xpantastic@..., "takisdamaschis"
<takisdamaschis@> wrote:

--- In xpantastic@..., "Karl" <shire03@>

wrote:

Hi Karl,
done everything you pointed out,no improvements!
Anything else you can think of before we go for the

DAC?

Thanks,Takis.

Hi Takis,

I also noticed that I get 3.79V at one of the

pins

of

U815

instead

of 4.0V(+/- .05V) as the service manual points

out!

Okay, lets look at D805, A zener diode which

provides

the

reference

for the DAC.Measure this with a good voltmeter, it

should

be

6.9V.

Again, try reflowing the solder around this part

and

the

ref

circuit.

If you have a service
manual, Look at the circuit around U815 and reflow

all

the

solder

around this part and the resistors capacitors etc...
Try this and let me know.

Karl



--- In xpantastic@..., "takisdamaschis"
<takisdamaschis@> wrote:

Hi Karl,
I have gone and replaced all parts you suggested,

re-

seated

the

dac

and went over all solders!
No improvement, I keep getting the same problem!
I also noticed that I get 3.79V at one of the

pins

of

U815

instead

of

4.0V(+/- .05V) as the service manual points out!
Anyway the good news is that I found a NOS dac

($150)

which

I

will

try

out as soon as it gets in(in a few days I hope).
I'll let you know!
Thanks,Takis.


--- In xpantastic@..., "Karl"

<shire03@>

wrote:

Hi Takis,
The other caps are Cx33 and Cx37 with x being

2,3,4,5,6,7

for

each

voice respectivly. And Yes they are the same

2.2uF

50V

Make

sure

they

are 50V rating. and correct polarity (You

probobly

knew

that)

But before you replace those, try this.You are

saying

you

are

having

problems with all the voices right?
This points to the main DAC/Tuming circuit as

you

have

already

guessed.

I would look closely at:
U811 The DAC
U816,U805 Multiplexer 4051
U812,U815,U813 Op Amps TLO81,TLO84,TLO81
U814 Analog Switch 4053

Any of these parts failing could cause tuning

problems

like

you

describe.
Now, before you replace them carfully pull them

from

the

sockets

and

re-seat them. Sometimes corrosion on the

socket/chip

lead

can

cause

a "not to good" connection. Also before I

replaced

them I

would

reflow the solder on the bottom of the board,

as

bad

solder

joints

could also cause this.
If this does not work replace em. All except

the

DAC

are

readily

available. I would wait till you replaced the

other

chips

before

you

went searching for this DAC to see if any

others

are

the

cause.

If

one of the chips have failed, I would bet on

the

mux

or

analog

switch.

It would not hurt to replace the capacitors I

mentioned

above, as

they are probobly on their way out anyway.

Let Me Know How It Goes

Karl


--- In

xpantastic@..., "takisdamaschis"

<takisdamaschis@> wrote:

Hi Carl,
yes I replaced all six Cx49 capacitors!
What number are the other ones you're

refering

to?

Are

they

also

2.2uF?

Many thanks,Takis.


--- In xpantastic@..., "Karl"

<shire03@>

wrote:

Hello takisdamaschis,

When you say output capacitors, are you

talking

about

the

small

2.2uF

Cx49 at the edge of the voice board? There

is

one

for

each

voice.

There is also one of these at the output of

each

VCO

feeding

the

VCF

If these go you can have tuning problems.

Also,

try

resetting

the

software.( hold sown clear and turn power

On)

Karl


--- In

xpantastic@..., "takisdamaschis"

<takisdamaschis@> wrote:

Hi everyone, my xpander seems to fail the

VCO

tune

test

randomly!some

voices fail during one test and pass on

the

next!

there

is

no

cosistancy on the voices that fail,it can

be

any

one of

them!

Some

times(rarely) the vco test passes! I have

the

same

problem

sometimes

with the Resonance and VCF but not as

often!

I have totally rebuilt the power

supply,changed

the

battery

and

output

bypass capacitors!All currents measure

right so

this is

not

a

voltage

supply problem!
The only other part I can think of is the

DAC

or

maybe

the

Timer?

Any thoughts?
Takis.

Hi Takis,

Does that mean that the DAC is faulty?

Could Be, What happens if you put the old one back in, And check
it's calibration, from pin 6 of U815?

Karl


--- In xpantastic@..., "takisdamaschis"
<takisdamaschis@...> wrote:

Hi Karl,
I did the calibration procedure but unfortunately I can't get the

DAC

trimmed down to 0volts!It keeps showing 4v(pin 6)!
Does that mean that the DAC is faulty?

--- In xpantastic@..., "Karl" <shire03@> wrote:

Hi Takis,
On page 34 of the Xpander service manual there is a DAC

calibrtion

procedure. A different chip would need a calibration.
What about the reference voltage?

Karl





--- In xpantastic@..., "takisdamaschis"
<takisdamaschis@> wrote:

Hi Karl,
I just got the new DAC! It's an HS3140C.I installed it
and.....nothing!Every test fails now instead of only some VCO's!
My original DAC is an MP7614KN, are these two incompatible and

if so

why are they mentioned as both able to do the job?
Furtermore is there anything else I should have done when I

replaced

the DAC that is not mentioned in the manual?
Thanks,Takis.


--- In xpantastic@..., "Karl" <shire03@> wrote:

Hi Takis,
I measured the D805 in mine: 6.95 Vdc. I notice it's a diode

in a

transistor package. This is a very accurate reference diode.

It

should read at least 6.9 Volts. Pin 1 is not used. I measured

from

The left side of R856 ( just below it) to the middle leg of

the

diode. My schematics identify this as a 6.9 V Zener. If the

one

in

yours shows a lower voltage than that, maybe this is causing

the

tuning errors. The diode may not be bad, something maybe

dragging it

down. I would take U815 out (turn Off first), then measure it

again.

If you can't get 6.9V out of that ref, I would replace it.
BTW about where is the adjustment trimmer pointing?

Karl




--- In xpantastic@..., "takisdamaschis"
<takisdamaschis@> wrote:

Hi Karl,
the voltmeter reads 6.38v!
Takis.

--- In xpantastic@..., "Karl" <shire03@> wrote:

Hi Takis,

What does the your voltmeter read when you measure the

zener

(D805)?

I keep thinking it's something to do with this circuit.
I am going to open mine up and see what I get.

Karl



--- In xpantastic@..., "takisdamaschis"
<takisdamaschis@> wrote:

--- In xpantastic@..., "Karl" <shire03@>

wrote:

Hi Karl,
done everything you pointed out,no improvements!
Anything else you can think of before we go for the DAC?
Thanks,Takis.

Hi Takis,

I also noticed that I get 3.79V at one of the pins

of

U815

instead

of 4.0V(+/- .05V) as the service manual points out!

Okay, lets look at D805, A zener diode which provides

the

reference

for the DAC.Measure this with a good voltmeter, it

should

be

6.9V.

Again, try reflowing the solder around this part and

the

ref

circuit.

If you have a service
manual, Look at the circuit around U815 and reflow

all

the

solder

around this part and the resistors capacitors etc...
Try this and let me know.

Karl



--- In xpantastic@..., "takisdamaschis"
<takisdamaschis@> wrote:

Hi Karl,
I have gone and replaced all parts you suggested,

re-

seated

the

dac

and went over all solders!
No improvement, I keep getting the same problem!
I also noticed that I get 3.79V at one of the pins

of

U815

instead

of

4.0V(+/- .05V) as the service manual points out!
Anyway the good news is that I found a NOS dac

($150)

which

I

will

try

out as soon as it gets in(in a few days I hope).
I'll let you know!
Thanks,Takis.


--- In xpantastic@..., "Karl"

<shire03@>

wrote:

Hi Takis,
The other caps are Cx33 and Cx37 with x being

2,3,4,5,6,7

for

each

voice respectivly. And Yes they are the same

2.2uF

50V

Make

sure

they

are 50V rating. and correct polarity (You

probobly

knew

that)

But before you replace those, try this.You are

saying

you

are

having

problems with all the voices right?
This points to the main DAC/Tuming circuit as you

have

already

guessed.

I would look closely at:
U811 The DAC
U816,U805 Multiplexer 4051
U812,U815,U813 Op Amps TLO81,TLO84,TLO81
U814 Analog Switch 4053

Any of these parts failing could cause tuning

problems

like

you

describe.
Now, before you replace them carfully pull them

from

the

sockets

and

re-seat them. Sometimes corrosion on the

socket/chip

lead

can

cause

a "not to good" connection. Also before I

replaced

them I

would

reflow the solder on the bottom of the board, as

bad

solder

joints

could also cause this.
If this does not work replace em. All except the

DAC

are

readily

available. I would wait till you replaced the

other

chips

before

you

went searching for this DAC to see if any others

are

the

cause.

If

one of the chips have failed, I would bet on the

mux

or

analog

switch.

It would not hurt to replace the capacitors I

mentioned

above, as

they are probobly on their way out anyway.

Let Me Know How It Goes

Karl


--- In

xpantastic@..., "takisdamaschis"

<takisdamaschis@> wrote:

Hi Carl,
yes I replaced all six Cx49 capacitors!
What number are the other ones you're refering

to?

Are

they

also

2.2uF?

Many thanks,Takis.


--- In xpantastic@..., "Karl"

<shire03@>

wrote:

Hello takisdamaschis,

When you say output capacitors, are you

talking

about

the

small

2.2uF

Cx49 at the edge of the voice board? There is

one

for

each

voice.

There is also one of these at the output of

each

VCO

feeding

the

VCF

If these go you can have tuning problems.

Also,

try

resetting

the

software.( hold sown clear and turn power On)

Karl


--- In

xpantastic@..., "takisdamaschis"

<takisdamaschis@> wrote:

Hi everyone, my xpander seems to fail the

VCO

tune

test

randomly!some

voices fail during one test and pass on the

next!

there

is

no

cosistancy on the voices that fail,it can

be

any

one of

them!

Some

times(rarely) the vco test passes! I have

the

same

problem

sometimes

with the Resonance and VCF but not as often!
I have totally rebuilt the power

supply,changed

the

battery

and

output

bypass capacitors!All currents measure

right so

this is

not

a

voltage

supply problem!
The only other part I can think of is the

DAC

or

maybe

the

Timer?

Any thoughts?
Takis.

Hi Karl,
I did the calibration procedure but unfortunately I can't get the DAC
trimmed down to 0volts!It keeps showing 4v(pin 6)!
Does that mean that the DAC is faulty?

Hi Takis,
On page 34 of the Xpander service manual there is a DAC calibrtion
procedure. A different chip would need a calibration.
What about the reference voltage?

Karl





--- In xpantastic@..., "takisdamaschis"
<takisdamaschis@...> wrote:

Hi Karl,
I just got the new DAC! It's an HS3140C.I installed it
and.....nothing!Every test fails now instead of only some VCO's!
My original DAC is an MP7614KN, are these two incompatible and if so
why are they mentioned as both able to do the job?
Furtermore is there anything else I should have done when I replaced
the DAC that is not mentioned in the manual?
Thanks,Takis.


--- In xpantastic@..., "Karl" <shire03@> wrote:

Hi Takis,
I measured the D805 in mine: 6.95 Vdc. I notice it's a diode in a
transistor package. This is a very accurate reference diode. It
should read at least 6.9 Volts. Pin 1 is not used. I measured

from

The left side of R856 ( just below it) to the middle leg of the
diode. My schematics identify this as a 6.9 V Zener. If the one

in

yours shows a lower voltage than that, maybe this is causing the
tuning errors. The diode may not be bad, something maybe

dragging it

down. I would take U815 out (turn Off first), then measure it

again.

If you can't get 6.9V out of that ref, I would replace it.
BTW about where is the adjustment trimmer pointing?

Karl




--- In xpantastic@..., "takisdamaschis"
<takisdamaschis@> wrote:

Hi Karl,
the voltmeter reads 6.38v!
Takis.

--- In xpantastic@..., "Karl" <shire03@> wrote:

Hi Takis,

What does the your voltmeter read when you measure the zener

(D805)?

I keep thinking it's something to do with this circuit.
I am going to open mine up and see what I get.

Karl



--- In xpantastic@..., "takisdamaschis"
<takisdamaschis@> wrote:

--- In xpantastic@..., "Karl" <shire03@> wrote:

Hi Karl,
done everything you pointed out,no improvements!
Anything else you can think of before we go for the DAC?
Thanks,Takis.

Hi Takis,

I also noticed that I get 3.79V at one of the pins of

U815

instead

of 4.0V(+/- .05V) as the service manual points out!

Okay, lets look at D805, A zener diode which provides the

reference

for the DAC.Measure this with a good voltmeter, it should

be

6.9V.

Again, try reflowing the solder around this part and the

ref

circuit.

If you have a service
manual, Look at the circuit around U815 and reflow all

the

solder

around this part and the resistors capacitors etc...
Try this and let me know.

Karl



--- In xpantastic@..., "takisdamaschis"
<takisdamaschis@> wrote:

Hi Karl,
I have gone and replaced all parts you suggested, re-

seated

the

dac

and went over all solders!
No improvement, I keep getting the same problem!
I also noticed that I get 3.79V at one of the pins of

U815

instead

of

4.0V(+/- .05V) as the service manual points out!
Anyway the good news is that I found a NOS dac ($150)

which

I

will

try

out as soon as it gets in(in a few days I hope).
I'll let you know!
Thanks,Takis.


--- In xpantastic@..., "Karl" <shire03@>

wrote:

Hi Takis,
The other caps are Cx33 and Cx37 with x being

2,3,4,5,6,7

for

each

voice respectivly. And Yes they are the same 2.2uF

50V

Make

sure

they

are 50V rating. and correct polarity (You probobly

knew

that)

But before you replace those, try this.You are saying

you

are

having

problems with all the voices right?
This points to the main DAC/Tuming circuit as you

have

already

guessed.

I would look closely at:
U811 The DAC
U816,U805 Multiplexer 4051
U812,U815,U813 Op Amps TLO81,TLO84,TLO81
U814 Analog Switch 4053

Any of these parts failing could cause tuning

problems

like

you

describe.
Now, before you replace them carfully pull them from

the

sockets

and

re-seat them. Sometimes corrosion on the socket/chip

lead

can

cause

a "not to good" connection. Also before I replaced

them I

would

reflow the solder on the bottom of the board, as bad

solder

joints

could also cause this.
If this does not work replace em. All except the DAC

are

readily

available. I would wait till you replaced the other

chips

before

you

went searching for this DAC to see if any others are

the

cause.

If

one of the chips have failed, I would bet on the mux

or

analog

switch.

It would not hurt to replace the capacitors I

mentioned

above, as

they are probobly on their way out anyway.

Let Me Know How It Goes

Karl


--- In xpantastic@..., "takisdamaschis"
<takisdamaschis@> wrote:

Hi Carl,
yes I replaced all six Cx49 capacitors!
What number are the other ones you're refering to?

Are

they

also

2.2uF?

Many thanks,Takis.


--- In xpantastic@..., "Karl"

<shire03@>

wrote:

Hello takisdamaschis,

When you say output capacitors, are you talking

about

the

small

2.2uF

Cx49 at the edge of the voice board? There is one

for

each

voice.

There is also one of these at the output of each

VCO

feeding

the

VCF

If these go you can have tuning problems. Also,

try

resetting

the

software.( hold sown clear and turn power On)

Karl


--- In

xpantastic@..., "takisdamaschis"

<takisdamaschis@> wrote:

Hi everyone, my xpander seems to fail the VCO

tune

test

randomly!some

voices fail during one test and pass on the

next!

there

is

no

cosistancy on the voices that fail,it can be

any

one of

them!

Some

times(rarely) the vco test passes! I have the

same

problem

sometimes

with the Resonance and VCF but not as often!
I have totally rebuilt the power supply,changed

the

battery

and

output

bypass capacitors!All currents measure right so

this is

not

a

voltage

supply problem!
The only other part I can think of is the DAC

or

maybe

the

Timer?

Any thoughts?
Takis.

Hi Karl,
I just got the new DAC! It's an HS3140C.I installed it
and.....nothing!Every test fails now instead of only some VCO's!
My original DAC is an MP7614KN, are these two incompatible and if so
why are they mentioned as both able to do the job?
Furtermore is there anything else I should have done when I replaced
the DAC that is not mentioned in the manual?
Thanks,Takis.

Hi Tony,
I'm talking about D805 at the DAC circuit!



--- In xpantastic@..., "Tony Cappellini" <cappy2112@...>
wrote:

Hello Takis

Where did you make the measurement?
This sounds somewhat like the reading I got- when I measured one of the
diodes near the battery. (as directed in the service manual test

procedure)

On Thu, Oct 2, 2008 at 1:12 AM, takisdamaschis

<takisdamaschis@...>wrote:

Hi Karl,
the voltmeter reads 6.38v!

Takis.

--- In xpantastic@... <xpantastic%40yahoogroups.com>,

"Karl"

<shire03@> wrote:

Hi Takis,

What does the your voltmeter read when you measure the zener(D805)?
I keep thinking it's something to do with this circuit.
I am going to open mine up and see what I get.

Karl



--- In xpantastic@... <xpantastic%40yahoogroups.com>,

"takisdamaschis"

<takisdamaschis@> wrote:

--- In xpantastic@... <xpantastic%40yahoogroups.com>,

"Karl" <shire03@> wrote:

Hi Karl,
done everything you pointed out,no improvements!
Anything else you can think of before we go for the DAC?
Thanks,Takis.

Hi Takis,

I also noticed that I get 3.79V at one of the pins of U815

instead

of 4.0V(+/- .05V) as the service manual points out!

Okay, lets look at D805, A zener diode which provides the

reference

for the DAC.Measure this with a good voltmeter, it should be

6.9V.

Again, try reflowing the solder around this part and the ref

circuit.

If you have a service
manual, Look at the circuit around U815 and reflow all the

solder

around this part and the resistors capacitors etc...
Try this and let me know.

Karl



--- In xpantastic@...

<xpantastic%40yahoogroups.com>,

"takisdamaschis"

<takisdamaschis@> wrote:

Hi Karl,
I have gone and replaced all parts you suggested,

re-seated the

dac

and went over all solders!
No improvement, I keep getting the same problem!
I also noticed that I get 3.79V at one of the pins of U815

instead

of

4.0V(+/- .05V) as the service manual points out!
Anyway the good news is that I found a NOS dac ($150) which I

will

try

out as soon as it gets in(in a few days I hope).
I'll let you know!
Thanks,Takis.


--- In xpantastic@...

<xpantastic%40yahoogroups.com>,

"Karl" <shire03@> wrote:

Hi Takis,
The other caps are Cx33 and Cx37 with x being

2,3,4,5,6,7 for

each

voice respectivly. And Yes they are the same 2.2uF 50V Make

sure

they

are 50V rating. and correct polarity (You probobly knew

that)

But before you replace those, try this.You are saying

you are

having

problems with all the voices right?
This points to the main DAC/Tuming circuit as you have

already

guessed.

I would look closely at:
U811 The DAC
U816,U805 Multiplexer 4051
U812,U815,U813 Op Amps TLO81,TLO84,TLO81
U814 Analog Switch 4053

Any of these parts failing could cause tuning problems like

you

describe.
Now, before you replace them carfully pull them from the

sockets

and

re-seat them. Sometimes corrosion on the socket/chip

lead can

cause

a "not to good" connection. Also before I replaced them I

would

reflow the solder on the bottom of the board, as bad solder

joints

could also cause this.
If this does not work replace em. All except the DAC are

readily

available. I would wait till you replaced the other chips

before

you

went searching for this DAC to see if any others are the

cause.

If

one of the chips have failed, I would bet on the mux or

analog

switch.

It would not hurt to replace the capacitors I mentioned

above, as

they are probobly on their way out anyway.

Let Me Know How It Goes

Karl


--- In xpantastic@...

<xpantastic%40yahoogroups.com>,

"takisdamaschis"

<takisdamaschis@> wrote:

Hi Carl,
yes I replaced all six Cx49 capacitors!
What number are the other ones you're refering to?Are they

also

2.2uF?

Many thanks,Takis.


--- In

xpantastic@...<xpantastic%40yahoogroups.com>,

"Karl" <shire03@> wrote:

Hello takisdamaschis,

When you say output capacitors, are you talking

about the

small

2.2uF

Cx49 at the edge of the voice board? There is one for

each

voice.

There is also one of these at the output of each VCO

feeding

the

VCF

If these go you can have tuning problems. Also, try

resetting

the

software.( hold sown clear and turn power On)

Karl


--- In

xpantastic@...<xpantastic%40yahoogroups.com>,

"takisdamaschis"

<takisdamaschis@> wrote:

Hi everyone, my xpander seems to fail the VCO tune

test

randomly!some

voices fail during one test and pass on the next!

there

is

no

cosistancy on the voices that fail,it can be any

one of

them!

Some

times(rarely) the vco test passes! I have the same

problem

sometimes

with the Resonance and VCF but not as often!
I have totally rebuilt the power supply,changed the

battery

and

output

bypass capacitors!All currents measure right so

this is

not

a

voltage

supply problem!
The only other part I can think of is the DAC or maybe

the

Timer?

Any thoughts?
Takis.

Hi Takis,
I measured the D805 in mine: 6.95 Vdc. I notice it's a diode in a
transistor package. This is a very accurate reference diode. It
should read at least 6.9 Volts. Pin 1 is not used. I measured from
The left side of R856 ( just below it) to the middle leg of the
diode. My schematics identify this as a 6.9 V Zener. If the one in
yours shows a lower voltage than that, maybe this is causing the
tuning errors. The diode may not be bad, something maybe dragging it
down. I would take U815 out (turn Off first), then measure it again.
If you can't get 6.9V out of that ref, I would replace it.
BTW about where is the adjustment trimmer pointing?

Karl




--- In xpantastic@..., "takisdamaschis"
<takisdamaschis@...> wrote:

Hi Karl,
the voltmeter reads 6.38v!
Takis.

--- In xpantastic@..., "Karl" <shire03@> wrote:

Hi Takis,

What does the your voltmeter read when you measure the zener

(D805)?

I keep thinking it's something to do with this circuit.
I am going to open mine up and see what I get.

Karl



--- In xpantastic@..., "takisdamaschis"
<takisdamaschis@> wrote:

--- In xpantastic@..., "Karl" <shire03@> wrote:

Hi Karl,
done everything you pointed out,no improvements!
Anything else you can think of before we go for the DAC?
Thanks,Takis.

Hi Takis,

I also noticed that I get 3.79V at one of the pins of U815

instead

of 4.0V(+/- .05V) as the service manual points out!

Okay, lets look at D805, A zener diode which provides the

reference

for the DAC.Measure this with a good voltmeter, it should be

6.9V.

Again, try reflowing the solder around this part and the ref

circuit.

If you have a service
manual, Look at the circuit around U815 and reflow all the

solder

around this part and the resistors capacitors etc...
Try this and let me know.

Karl



--- In xpantastic@..., "takisdamaschis"
<takisdamaschis@> wrote:

Hi Karl,
I have gone and replaced all parts you suggested, re-seated

the

dac

and went over all solders!
No improvement, I keep getting the same problem!
I also noticed that I get 3.79V at one of the pins of U815

instead

of

4.0V(+/- .05V) as the service manual points out!
Anyway the good news is that I found a NOS dac ($150) which

I

will

try

out as soon as it gets in(in a few days I hope).
I'll let you know!
Thanks,Takis.


--- In xpantastic@..., "Karl" <shire03@> wrote:

Hi Takis,
The other caps are Cx33 and Cx37 with x being 2,3,4,5,6,7

for

each

voice respectivly. And Yes they are the same 2.2uF 50V

Make

sure

they

are 50V rating. and correct polarity (You probobly knew

that)

But before you replace those, try this.You are saying you

are

having

problems with all the voices right?
This points to the main DAC/Tuming circuit as you have

already

guessed.

I would look closely at:
U811 The DAC
U816,U805 Multiplexer 4051
U812,U815,U813 Op Amps TLO81,TLO84,TLO81
U814 Analog Switch 4053

Any of these parts failing could cause tuning problems

like

you

describe.
Now, before you replace them carfully pull them from the

sockets

and

re-seat them. Sometimes corrosion on the socket/chip lead

can

cause

a "not to good" connection. Also before I replaced them I

would

reflow the solder on the bottom of the board, as bad

solder

joints

could also cause this.
If this does not work replace em. All except the DAC are

readily

available. I would wait till you replaced the other chips

before

you

went searching for this DAC to see if any others are the

cause.

If

one of the chips have failed, I would bet on the mux or

analog

switch.

It would not hurt to replace the capacitors I mentioned

above, as

they are probobly on their way out anyway.

Let Me Know How It Goes

Karl


--- In xpantastic@..., "takisdamaschis"
<takisdamaschis@> wrote:

Hi Carl,
yes I replaced all six Cx49 capacitors!
What number are the other ones you're refering to?Are

they

also

2.2uF?

Many thanks,Takis.


--- In xpantastic@..., "Karl" <shire03@>

wrote:

Hello takisdamaschis,

When you say output capacitors, are you talking about

the

small

2.2uF

Cx49 at the edge of the voice board? There is one for

each

voice.

There is also one of these at the output of each VCO

feeding

the

VCF

If these go you can have tuning problems. Also, try

resetting

the

software.( hold sown clear and turn power On)

Karl


--- In xpantastic@..., "takisdamaschis"
<takisdamaschis@> wrote:

Hi everyone, my xpander seems to fail the VCO tune

test

randomly!some

voices fail during one test and pass on the next!

there

is

no

cosistancy on the voices that fail,it can be any

one of

them!

Some

times(rarely) the vco test passes! I have the same

problem

sometimes

with the Resonance and VCF but not as often!
I have totally rebuilt the power supply,changed the

battery

and

output

bypass capacitors!All currents measure right so

this is

not

a

voltage

supply problem!
The only other part I can think of is the DAC or

maybe

the

Timer?

Any thoughts?
Takis.

Hi,
are you talking about the D805 diode?
If so, mine does not have a capacitor parallel to it!
Did yours have one all along? If so please let me know of it's specs
so that I can add one myself!
Thanks!


--- In xpantastic@..., "bjorn roland" <bjorn.roland@...>
wrote:

Tip...
A zener diode is always "noisy". It generates ripples in the voltage.
Ripples in referance voltage may cause autotune to fail.
To avoid these ripples there is always a capacitor mounted in

paralell to

the zener
to flatten out these ripples. Check ac voltage also, not only dc.
Ac will show ripples. Should be zero, but if not check out this

capacitor.

On Thu, Oct 2, 2008 at 5:02 PM, Tony Cappellini <cappy2112@...> wrote:

Hello Takis

Where did you make the measurement?
This sounds somewhat like the reading I got- when I measured one

of the

diodes near the battery. (as directed in the service manual test

procedure)

On Thu, Oct 2, 2008 at 1:12 AM, takisdamaschis

<takisdamaschis@...>wrote:

Hi Karl,
the voltmeter reads 6.38v!

Takis.

--- In xpantastic@... <xpantastic%40yahoogroups.com>,

"Karl"

<shire03@> wrote:

Hi Takis,

What does the your voltmeter read when you measure the zener(D805)?
I keep thinking it's something to do with this circuit.
I am going to open mine up and see what I get.

Karl



--- In xpantastic@... <xpantastic%40yahoogroups.com>,

"takisdamaschis"

<takisdamaschis@> wrote:

--- In xpantastic@... <xpantastic%40yahoogroups.com>,

"Karl" <shire03@> wrote:

Hi Karl,
done everything you pointed out,no improvements!
Anything else you can think of before we go for the DAC?
Thanks,Takis.

Hi Takis,

I also noticed that I get 3.79V at one of the pins of U815

instead

of 4.0V(+/- .05V) as the service manual points out!

Okay, lets look at D805, A zener diode which provides the

reference

for the DAC.Measure this with a good voltmeter, it should be

6.9V.

Again, try reflowing the solder around this part and the ref

circuit.

If you have a service
manual, Look at the circuit around U815 and reflow all the

solder

around this part and the resistors capacitors etc...
Try this and let me know.

Karl



--- In xpantastic@...

<xpantastic%40yahoogroups.com>,

"takisdamaschis"

<takisdamaschis@> wrote:

Hi Karl,
I have gone and replaced all parts you suggested,

re-seated the

dac

and went over all solders!
No improvement, I keep getting the same problem!
I also noticed that I get 3.79V at one of the pins of U815

instead

of

4.0V(+/- .05V) as the service manual points out!
Anyway the good news is that I found a NOS dac ($150) which I

will

try

out as soon as it gets in(in a few days I hope).
I'll let you know!
Thanks,Takis.


--- In xpantastic@...

<xpantastic%40yahoogroups.com>,

"Karl" <shire03@> wrote:

Hi Takis,
The other caps are Cx33 and Cx37 with x being

2,3,4,5,6,7 for

each

voice respectivly. And Yes they are the same 2.2uF 50V Make

sure

they

are 50V rating. and correct polarity (You probobly knew

that)

But before you replace those, try this.You are saying

you are

having

problems with all the voices right?
This points to the main DAC/Tuming circuit as you have

already

guessed.

I would look closely at:
U811 The DAC
U816,U805 Multiplexer 4051
U812,U815,U813 Op Amps TLO81,TLO84,TLO81
U814 Analog Switch 4053

Any of these parts failing could cause tuning problems like

you

describe.
Now, before you replace them carfully pull them from the

sockets

and

re-seat them. Sometimes corrosion on the socket/chip

lead can

cause

a "not to good" connection. Also before I replaced them I

would

reflow the solder on the bottom of the board, as bad solder

joints

could also cause this.
If this does not work replace em. All except the DAC are

readily

available. I would wait till you replaced the other chips

before

you

went searching for this DAC to see if any others are the

cause.

If

one of the chips have failed, I would bet on the mux or

analog

switch.

It would not hurt to replace the capacitors I mentioned

above, as

they are probobly on their way out anyway.

Let Me Know How It Goes

Karl


--- In

xpantastic@...<xpantastic%40yahoogroups.com>,

"takisdamaschis"

<takisdamaschis@> wrote:

Hi Carl,
yes I replaced all six Cx49 capacitors!
What number are the other ones you're refering to?Are

they

also

2.2uF?

Many thanks,Takis.


--- In

xpantastic@...<xpantastic%40yahoogroups.com>,

"Karl" <shire03@> wrote:

Hello takisdamaschis,

When you say output capacitors, are you talking

about the

small

2.2uF

Cx49 at the edge of the voice board? There is one for

each

voice.

There is also one of these at the output of each VCO

feeding

the

VCF

If these go you can have tuning problems. Also, try

resetting

the

software.( hold sown clear and turn power On)

Karl


--- In

xpantastic@...<xpantastic%40yahoogroups.com>,

"takisdamaschis"

<takisdamaschis@> wrote:

Hi everyone, my xpander seems to fail the VCO

tune test

randomly!some

voices fail during one test and pass on the next!

there

is

no

cosistancy on the voices that fail,it can be any

one of

them!

Some

times(rarely) the vco test passes! I have the same

problem

sometimes

with the Resonance and VCF but not as often!
I have totally rebuilt the power supply,changed the

battery

and

output

bypass capacitors!All currents measure right so

this is

not

a

voltage

supply problem!
The only other part I can think of is the DAC or

maybe

the

Timer?

Any thoughts?
Takis.

Hi Karl,
the voltmeter reads 6.38v!
Takis.