sequencer not working

[guest]

check your multimeter to see if its measuring right
measure a new 9v or 1.5v battery

what is the part number on ic20
what are the voltages on ic20

[Mussi81]

check your multimeter to see if its measuring right
measure a new 9v or 1.5v battery

what is the part number on ic20
what are the voltages on ic20

checked my meter ok on some batteries

the part number on ic20 is "ts7085"
i cant get the correct voltage on ic20 but i can get the correct voltages at j4!

the middle pad on ic20 might be have a bad connection, can i connect this to another point on the board?

[guest]

that can go to any good ground point
you can tell the ground pins
by the little cross hairs that connect to the groundplane

also
turn the x0x power off
and measure the resistance between
ground on the mainbaoard and ioboard
it sounds like there is something flakey

its a bit strange that the voltage would go up on the mainboard though
although a bad ground on ic20 would do that

[Mussi81]

that can go to any good ground point
you can tell the ground pins
by the little cross hairs that connect to the groundplane

also
turn the x0x power off
and measure the resistance between
ground on the mainbaoard and ioboard
it sounds like there is something flakey

its a bit strange that the voltage would go up on the mainboard though
although a bad ground on ic20 would do that

sorry for my ignorance but how do i check the resistance?

[Mussi81]

also alot of the led's dont light up when the buttons are pressed

[guest]

put your meter on resistance mode
its usually marked with an ohm symbol
turn the x0x off
put one probe on a ground point on the mainboard
put the other probe on a ground point on the ioboard

you can also check from the middle pin of ic20
to the ground on the ioboard
to see if its flakey
this is a likely cause of getting 6v on the mainboard

[Mussi81]

put your meter on resistance mode
its usually marked with an ohm symbol
turn the x0x off
put one probe on a ground point on the mainboard
put the other probe on a ground point on the ioboard

you can also check from the middle pin of ic20
to the ground on the ioboard
to see if its flakey
this is a likely cause of getting 6v on the mainboard

ok, i check from 1 of the switches tact switches to headphone jack and got 109.7k

and from the tack switch to the midde pin on ic 20 and got 15.83k

[guest]

the tact switches arent grounded

use the negative pin of c102 on the mainboard
and the negative pin of c3 on the ioboard
and then check the middle pin of ic20
to the negative pin of c3 on the ioboard

[Mussi81]

the tact switches arent grounded

use the negative pin of c102 on the mainboard
and the negative pin of c3 on the ioboard
and then check the middle pin of ic20
to the negative pin of c3 on the ioboard

c102 to c3 0.2

middle pin ic20 to c3 5.78

[guest]

try clipping the middle pin of ic20
back to ground
and see if you get 5v on the mainboard again

if you are still getting 6v on the mainboard
disconnect the mainboard from the ioboard
until you have a steady 5v
as 6v can damage some of the parts

[Mussi81]

try clipping the middle pin of ic20
back to ground
and see if you get 5v on the mainboard again

if you are still getting 6v on the mainboard
disconnect the mainboard from the ioboard
until you have a steady 5v
as 6v can damage some of the parts

this is all sorted now, i have 5v again.

resoldered ic20 again and i went through the manual checked everything again. everything is good except c3 is giving me 13.42 which is a bit low. i dont know if that is relevant or not?!?

so i still have the same issue, i can hear the sounds when pressing buttons in keyboard mode for a few seconds then the volume fades down, also some of the leds do not work.

along the way i had problems with ic6, is there a way to check if this is all ok?? i have a scope just not sure what to check!

thanks in advance

[guest]

13v on c3 is plenty

in keyboard mode
the note should fade out after a few seconds

does it sound ok when you play a pattern

which leds do not work

[Mussi81]

13v on c3 is plenty

in keyboard mode
the note should fade out after a few seconds

does it sound ok when you play a pattern

which leds do not work

when i turn the unit on lots dont work, from the keyboard top row, c# is the only working led. the bottom row g,b and c' are not working.

when i say the the volume fades, once its gone no sounds can be heard from any of the keys. i have to turn off and on again so i can hear the notes

[guest]

are you using a 9v AC wallwart

plug it in
and let the sound die out
and measure the 12v and 5.333v and 5v rails
make sure they are good

then do the headphone test on the vco and vcf
and see if there is still signal

if there is
put the x0x in keyboard mode
and measure the gate out
when you press a key
make sure it goes to 12v and back down to 0v

[Mussi81]

are you using a 9v AC wallwart

yes

plug it in
and let the sound die out
and measure the 12v and 5.333v and 5v rails
make sure they are good

all good

then do the headphone test on the vco and vcf
and see if there is still signal

went through the manual again and test all ok with a scope

if there is
put the x0x in keyboard mode
and measure the gate out
when you press a key
make sure it goes to 12v and back down to 0v

all the notes go between 0.44v and 11.52v when pressed