sequencer not working

[guest]

excellent
that helps a lot

put your scope on d37
either side is fine
and see if you get a pulse
when you trigger a note

if not
check the voltages on q38

[Mussi81]

excellent
that helps a lot

put your scope on d37
either side is fine
and see if you get a pulse
when you trigger a note

if not
check the voltages on q38

there is no pulse at d37 no movement at all on the scope

i can get 11.78vdc at q38

[guest]

place your scope on each pin of q38
and see what the waveforms look like
when you trigger a note

if the d37 point stays at 11v and doesnt change
then either q38 is bad
or there is short on r148 to ground

[Mussi81]

place your scope on each pin of q38
and see what the waveforms look like
when you trigger a note

if the d37 point stays at 11v and doesnt change
then either q38 is bad
or there is short on r148 to ground

nothing happened at q38 so i replaced it, still nothing happens

how do i sort r148. replace it?

[guest]

measure the resistance to ground
from both sides of r148

what are the voltages
on all pins of q38
both with and without a note being held

[Mussi81]

measure the resistance to ground
from both sides of r148

what are the voltages
on all pins of q38
both with and without a note being held

resistance 12.60k and fluctuates between 22k and 28k

if i clip the ground cable to the middle pin i get 11.80vdc note off and on

grounded to voltage regulator i get 11.80 on and off, - 6.73 on and off, 5.14 on and off

[guest]

is d37 orientated properly
if it is
measure the resistance across it
in both directions

did you mean 6.73 or -6.73v
there are no negative voltages inside the x0x

[guest]

with the ground clipped to the voltage regulator
measure the voltage at the following points

both sides of c54
both sides of r148
both sides of r149
both sides of r150
both sides of r151

it shouldnt matter with note on or note off
as it seems to be doing the same thing either way

[Mussi81]

is d37 orientated properly
if it is
measure the resistance across it
in both directions

did you mean 6.73 or -6.73v
there are no negative voltages inside the x0x

D37 is in correct way.

Resistance 27.8 and 254.5

Yes I did mean -6.73v

[guest]

the diode might be bad
it should have a higher resistance
in the backward direction

but check those voltages i mentioned
there shouldnt be any negative voltages

[Mussi81]

the diode might be bad
it should have a higher resistance
in the backward direction

but check those voltages i mentioned
there shouldnt be any negative voltages

Because I have been moving the two boards about too much some of the cables have broken at the connection. I will have tO get some new cables before I continue as this has already happened those ribbon cables in the bom are to thin

Maybe that is why there is a negative voltage?

[Mussi81]

This project is becoming painful

[guest]

the ribbon cables definitely arent good
for multiple opening and closings of the case

it will be worth it when its done