Rebote 2.5 prob

[Auke Haarsma]

Hi, I've read quite a few posts about the 2.5 (tonepad), but couldn't figure out what to do. Here's what happens.
In bypass: good sound.
With Effect on: Small drop in dry signal volume. Wet signal just ticks at the rate of the delay time (tick tick tick tick etc). Pots do work. Delay time affacts rate of the ticks, level can mute the wet signal. Repeats I can't judge. I don't get a delayed sound, just the ticks, so I don't know about the repeats. Delay set to about 200 ms during measuring below.

I got my MM and wrote down the voltages. When measuring the pins by holding the MM to the pins, some pins made the sound act weird, I noted that at the pins below:

PT2399
1: 4.2
2: 6.7 (min delay time when measured -> very fast ticks)
3: 9.1
4: 9.1
5: 4.8
6: 6.7 (doubled delay time between ticks)
7: 4.6
8: 4.6
9: 4.4
10: 8.9 (min delay time when measured -> very fast ticks)
11: 8.9
12: 4.4
13: 6.6 (ticks are gone, no other sound but the dry signal)
14 8.9
15: 4.2
16: 8

IC2 (TL072)
1: 4.6
2: 4.6 (buzzes)
3: 4.6 (humms when measured)
4: 0
5: 3.7 (LOUD buzzing/humming when measured)
6: 4.6 (LOUD buzz)
7: 4.6
8: 0

IC3
1: 4.5
2: 9
3: 0

Any clue based on these numbers where it goes wrong? Could I have fried something? I accidentially switched + and - on my adapter first time I tested the unit. It had been on for like just 10 seconds, but still I noticed some capacitors getting hot.

Any help is greatly appreciated!

[bioroids]

The voltages at the PT2399 are tottaly out of wack!

First you should have 5v at pin 1 (which is the power for the IC)
On most of the other pins you should have 2.5v which is the reference voltage internally generated by the IC

Is IC3 the voltage regulator? It should be closer to 5v at the output in that case.

I think you may well have fried the IC, or maybe placed it backwards?

Luck

Miguel

[Auke Haarsma]

thnx for the reply. The numbres are totally different indeed from reports of others I've read. However, does this always mean a defective/fried PT2399?

[sfr]

In my experience, over-voltaging the PT2399 fries it.  I wouldn't look there as the source of your problem, although you may very well need to replace it after everything else is fixed - I'd look at at the voltage regulator (IC3 - the three pin transistor shaped one)  I don't know which way you counted the pins, but looking at the schematic briefly, I'd think you would see 0 volts in the middle pin, since that's connected to ground.  9 Volts should come in on one of the outside pins (the one connected to pin 8 of the opamp and a 47uF cap) and something around 5v should come out the other one (the pin connected to another 47uF cap and pin one of the PT2399) 

I'm also wondering what's going on, because you should have 9v, not 0 on pin 8 of the TL072?  Could be something wrong with the build there that this is telling us, or the chip could be backwards, or perhaps you're just reading the pins wrong?

I usually socket my ICs and check voltage readings at the pins of the socket before I plug in the chips and power it up for the first time and make sure everything is okay.  Obviously voltage regulators throw a monkey wrench in the process, but it helps me avoid the inevitable.