Author Topic: Ibanez mini analog delay / Testing for bad components  (Read 179 times)

munkeyboy

Ibanez mini analog delay / Testing for bad components
« on: January 27, 2020, 10:18:27 PM »
I have this ibanez analog delay with V3208 bbd chips and a V3102 clock chip.   Trying to diagnose why there is no delay'd signal.  There is amplified signal, meaning there is a signal coming out that is a lot louder than going in.  However there is zero delay effect that i can detect.  I'm low-tech testing with my phone as input and headphones as output. 

I've already ruled out the bypass switch, the pots (i think) and made sure there was an additional non-conductive material between sandwiched boards.  The next target seems to be the chips, maybe the clock.  I jumpered my headphones to the each of the v3208 OUT channels.  All OUTs have sound, but there is a squeal overlayed on top. This could be normal and cause by the way I'm tapping in to the signal...idk.  The signal going to the IN channel of what I guess is the first bbd chip ,sounds ok as far as i can tell.   There are no repeats that i can hear coming out of any of those chips.  However they may be an initial delay.

I'm hoping for an easy fix like replacing a v3208 or v3102.  Any clue how a newb can test those chips?  I do okay with building or repairing my own amps and simple pedals, but this SMD stuff is hard to trace out.   I have a new scope, but still haven't worked out how to use it yet.

ElectricDruid

Re: Ibanez mini analog delay / Testing for bad components
« Reply #1 on: January 28, 2020, 09:02:53 AM »
If both the output pins on the V3208 have a signal, that's a good sign. That means the delay must be working, and that means the clock must be running too.
The squeal is normal since each signal is only half the waveform. It's "time sliced" up by the two clock signals, so for half the time one output produces the signal, and for the other half the other one does. When you mix them back together you get the whole thing.

It looks like maybe the delayed signal isn't making it to the output mixer. That could be due to dead FET switching (does this thing use FET switching? I'm guessing it does) not allowing the delayed signal through that path. Or it could be a bad connection to a delay level pot, or the pot itself gone bad (wiper lifted off the track, for example). There's a few possibilities.

The good news is it doesn't look like you need to replace the V3102 or V3208 from what you've said so far.

HTH,
Tom