Help with 1776 Multiplex Echo Machine

[THOMMO]

G'day folks, I'm having trouble with my 1776 MPEM build. I've had this on hand for a long time and have only now had the time to tackle it. It's probably the first build that I've actually taken the time to measure ALL of the components to get as close as possible to the correct values. Also paused for a month or so while waiting to get some parts that I lacked.

Firstly, I only had four PT2399's. One of which came out of the foam with pin 1 completely missing, lol! So down to only three from the start.

I have the 3pos rotary soldered to the back of the board, as per build doc. I made sure that the 'A, B, C and D pins of the switch matched up correctly. And have temporarily soldered in all other controls for testing. This morning I re-flowed all solder joints.

On to the problem! Placing each 2399 in turn into IC2 pos, with rotary on the EP-3 mode I get no delay, only dry signal. With the PCB fully loaded I get one single repeat only, in the centre position of the switch.

Here are my voltages with PT2399's OUT of the circuit.

Battery- 9.2v
All readings are in volts.

Reg
8.93
0.023
5.02

Q1
C 0.027
B 0.55
E 6.24

IC1
1. 4.47
2. 4.47
3. 4.47
4. .023
5. 4.47
6. 4.47
7. 4.47
8. 8.9

IC2
1. 0.014
2. 0.013
3. 0.013
4. 0.131 dropping
5. 0.181      "
6. 0.111      "
7. 3.0          "
8. 5.02
9. 0.217
10. 0.020
11. 0.020
12. 0.010
13. 0.020
14. 0.020
15. 0.010
16. 0.008

IC3
1. 5.02
2. 0.072
3. 0.020
4. 0.020
5. 0.012
6. 0.020
7. 0.184
8. 0.008
9. 0.010
10. 0.020
11. 0.160
12. 0.090
13. 0.050 dropping
14. 0.046      "
15. 0.060      "
16. 0.045      "

I haven't audio probed yet but I will when I have more time. Is there a point on IC2 I can go straight to to see if there is any signal coming out?

If there's more info needed, let me know.

Cheers Thommo.

[anotherjim]

You either have IC2 fitted backwards or have numbered the results backwards. Pin 1 of a PT2399 should have the +5v supply. Pins 3&4 should be 0v and then pin 2 should be an output from the chip of 2.5v. The rest are 2.5v also or something lower.

You IC3 has 5v on pin1 but is failing to produce its 2.5v reference on pin2. That means either a bad chip or a short circuit somewhere connecting to pin2.

[THOMMO]

Well anotherjim, you hit the nail on the head. That was the uppercut I needed 
I got home from work(12:10am here in Australia) and looked at the board thinking I had even put in my sockets the way I was loading IC2 but.......no! I was just being dopey, to the limit of my own frustration lol!

Two out of my three chips worked perfectly.

All is awesome now in delay land!

Thank you very much, kind Sir!

Cheers, Thommo.