[HELP!] - Mad Professor Deep Blue Delay Clone - Kit [ IC pin voltages]

[Pseudub11]

Hi guys,

I assambled a mad professor deep blue delay clone but doesn't want to work properly.

I buyed a kit [http://tagboardeffects.blogspot.co.uk/2012/02/mad-professor-deep-blue-delay.html] and assemble it, got a clear sound without distorse but only the volume pot works [ repeat/mix/delay are dead].

I measured the voltage from the PT2399 and i found out that the voltages are ok except two of them [pin 13 - LPF 2 IN /pin 14 - LPF 2 OUT].

On the left it's the "must be" value and on the right it's the voltage i have in the circuit :

PT2399
1 – 5.00 /4.96
2 – 2.48 / 2.48
3 – 0.00 / 0.00
4 - 0 .00 / 0.00
5 – 3.61 / 3.18
6 – 2.49 / 2.47
7 – 0.57 / 0.63
8 – 0.85 / 0.65
9 – 2.49 / 2.48
10 – 2.49 / 2.48
11 – 2.49 / 2.48
12 – 2.49 / 2.48
13 – 2.49 / 0
14 – 2.49 / 4.88
15 – 2.49 / 2.48
16 – 2.49 / 2.48

OP275
1 – 4.42 / 4.27
2 – 4.34 / 4.33
3 – 4.31 / 4.33
4 – 0.00 / 0
5 – 4.31 / 4.33
6 – 4.33 / 4.33
7 – 4.31 / 4.36
8 – 8.70 / 8.67

78L05 regulator
I – 8.69 / 8.67
G – 0.00 / 0
O – 5.00 / 4.96

Measured de parts [all good], the board [ok], wires&connections [all good].

Based on the schematic and the datails i got you, can you please help me make it work?

[nocentelli]

http://www.hqew.net/files/Images/Article/images/2_4(7).jpg

There's a block diagram of the PT2399 here. I don't have a great deal of understanding of what could cause the odd voltages at pin 13/14, you say the parts values and wiring are all OK, the obvious question is have you swapped the pt for a known good chip, as they can have known issues that differ from supplier to supplier and batch to batch, but the deep blue delay circuit is fairly forgiving.

For reference:

http://3.bp.blogspot.com/-bEMBMvJwA5Y/TwrbbnpmzoI/AAAAAAAAAbw/EQ70PKQOFes/s1600/seaUrchin_Schematic.gif

[PRR]

Welcome!

R11 R12 not really connecting pin 14 back to pin 13.

Pin 13 grounded (solder-hair).

Bad PT chip.

[jimilee]

In my experience with every incarnation of this circuit so far, you have to jumper pin 3 to pin 4, it is prone to locking up.