Zombie chorus with anti tick mod 1590b layout?..

[Scruffie]

Seems to me your 4047 is the culprit, replace it.

[deadastronaut]

okey dokey..i'll give it a whirl..cheers man!.

[Scruffie]

Wait, what am I saying, check for shorts etc. on the 4047, might be fine.

[deadastronaut]

i just changed the 4047, and 3007....no difference!..


ok i'll check the pins pcb side....fingers crossed!..

btw is the layout ok, i couldnt see anything different from the original (apart from the squeeze on size)

[deadastronaut]

hang on...i'm going to have to give myself a kicking, i didn't solder one of the @#$%ing chips pins arhhhhhh what a dumb @#$% i am...

there should be a head slap animation just for me!..

soldering iron on now....back in a bit, after i slap myself and shout at the nervous looking cat....


edit:  nope still the same...

[Scruffie]

hang on...i'm going to have to give myself a kicking, i didn't solder one of the @#$%ing chips pins arhhhhhh what a dumb @#$% i am...

there should be a head slap animation just for me!..

soldering iron on now....back in a bit, after i slap myself and shout at the nervous looking cat....

Haha, I did that when I built my A/DA a while back I remember, thankfully it was a quick 2 minute DMM probe and find, there was a lot of tiny holes to solder!

Right, let's see what happens with that soldered.

Layout I haven't checked over other than the power connections for the 4047, we'll assume it's okay for the moment.

[deadastronaut]

done...nope still the same!..

the cat looks scared now!..

[deadastronaut]

updated voltages, still no proper lfo/fluctuation

4047

1   3.69
2   0.13
3   2.99
4   3.92
5   3.92
6   3.92
7   0.00
8   0.00
9   0.00
10  1.90
11  1.92
12   0.00
13   3.70
14   3.91

3007

1   3.91
2   1.92
3   1.17
4   0.00
5   0.00
6   1.90
7   2.91
8   2.91

top 072

1  1.30
2  7.45
3  3.46
4  0.00
5  1.78/1.81..fluctuation
6  1.90
7  7.98
8  8.60

bottom 072

1  4.30
2  4.29
3  4.16
4  0.00
5  4.29
6  4.30
7  4.30
8  8.60

[Scruffie]

Voltage getting to the 4047 has gone up slightly... sure there's no shorts or anything? Still the case that removing the 3007 keeps the voltage the same?

We'll ignore the LFO for the moment, clock working is most imporant IMO.

But yeah the voltages on that LFO aren't right, i'm not sure if this LFO functions well with the TL072, might be a picky one... got a 1458?

Edit: Your 4047 & 3007 voltages look right to scale I think... just they shouldn't be down that low, is Q3 orientated correctly? i.e. you checked the datasheet vs schematic.

Something in this area is stopping them getting the right voltage, removing the 4047 brought it back up before... I briefly checked the layout and it seems okay around the LFO & Clock area...

[deadastronaut]

swapped top 072 for a 358../  no 1458

check pcb traces, all looks ok.

took out 3007,

3007 socket

1  6.18
2  3.05
3  6.15
4  0.00
5  0.00
6  3.04
7  6.97
8  6.97


getting fluctuation on the 358 now..

1   1.49- 1.62
2   3.59
3   3.45
4   0.00
5   1.96
6   1.90
7   3.15-410
8   8.84

[Scruffie]

And what are the new 4047 & 358 voltages, things are looking better without the 3007 in there.

[Scruffie]

Right, saw your edit, 358 seems to be working now, 4047 & Q3 voltages without the 3007 in?

[deadastronaut]

oops..4047 voltages with 4047 in..3007 out

1  5.11/5.13
2  0.10
3  4.21/4.25
4  5.34/5.35
5  5.34/5.35
6  5.34/5.35
7  0.00
8  0.00
9  0.00
10  2.63/2.64
11  2.65
12  0.00
13  5.11/5.13
14  5.33/5.34


Q3
C  8.84
B  6.40
E  5.33

[Scruffie]

Right... not much difference, the 3007 isn't causing the issue.

Looking back at your old transistor voltages, I notice actually they're all a bit off... Q1s Emitter is low, Q2s Base & Emitter should both be about half supply and Q3 is having its voltage dragged down... they definitley all orientated correctly? Schematic to layout to datasheet checked?

Going Down, Top 5088 should be E,B,C Middle should be C,B,E & Bottom C,B,E Left to Right... keep checking for shorts all round these areas.

[deadastronaut]

yep defo orientaed correctly..according to layout/s

i used 2x 3904's and 1x 3906 for q1...

i'll check em out and post voltages with the 3007 still out...

[deadastronaut]

Q3

C  8.84
B  6.92
E  6.45

Q2

C  8.84
B  8.84
E  0.00

Q1  3906

C  0.00
B  7.36
E  6.22

[Scruffie]

Q1 looks okay now, Q3 is still low (we assume pulled down by either the 4047 or something near by) and Q2 is still wrong, the emitter shouldn't be 0V.

Voltages of the MN3007, Q2 & 3 without the 4047... sorry this must be getting boring going back and forth.

[deadastronaut]

no worries man, i'm really glad of the help..

3007 back in, 4047 out...

3007

1  8.75
2  0.00
3  8.62
4  0.00
5  0.00
6  0.00
7  7.95
8  7.96

q3
c  8.85
b  8.70
e  8.66

q2

c  8.85
b  8.47
e  0.00

ive gone round the pcb with a tiny screwdriver scraping between the traces, especially round the trannies, all looks ok, (comparing to a spare copy of the pcb...)

[Scruffie]

Q2 still has nothing on the emitter... something going on there but I can't see what...

And the 4047 is pulling the voltage down for some reason... there's gotta be something in this area wrong.

Pin 3 of the 3007 is very high, how's your trimmer set, keep it in the mid position... you should see about half supply here...

Tried resoldering the any suspect joints?

[deadastronaut]

set the trim, now 5.5v...so iknow the trimmers ok now..

i'll whip the ic's out and try reflowing the solder and see how it goes....cheers man!..

btw,the cat looks petrified now!..