Troubleshooting an Ibanez FL-9

[ClenchedTeeth]

When I turn it on I get a clean signal - no effect at all. I had a look at the service manual (http://www.mojotronics.com/images/FL9.pdf) and it has a troubleshooting guide which mentions what to do if there is no effect (4th page), but it's a weird flow diagram with arrows and I don't understand what it is telling me to do. Am I supposed to look at the voltage on CP9 and make sure there is a clock signal there? And then if there is no signal i replace Q107 and 108 (dashed arrow)? And if there is a signal I go on to check (solid arrow) the "clock divider/driver"?
Anyone got any experience with this sort of thing?

As an aside I should mention that it used to SOMETIMES work about 20 seconds after I turned it on, but even then it sounded sort of sick and not very 'flangey'.

[George Giblet]

Your interpretation is pretty much there.   It assumes you are injecting a sine-wave into the input using an oscillator.

Sometimes if you blindly follow those repair charts you end-up changing a lot of stuff and if it's a costly or hard to get IC you can waste a lot of money and time.

I have a feeling your problem is the depth pot.  The wiper might be dirty/faulty.

[cjlectronics]

The flow diagram is well done.  It is a step by step method in troubleshooting problems. As Mr. Giblet states, the technician is expected to have a function generator and an O-scope when troubleshooting this pedal.   Your description of the Clock Divider Driver is how I would approach it as the troubleshooting guide for that section is misleading.  Basically, if the clock signal is good, then I'd check for a signal into the BBD and a delayed signal out of the BBD( See CP7).

For example, to check the power supply, measure points CP2, CP3, and CP10 for 4.5v, 5v, and 9v using a DVM. If they measure good then move down to the Buffer & Pre Emphasis section and measure CP4... if the signal does not look like the chart then replace IC101.

I would look at the electrolytic capacitors.  For the age of the pedal these are susceptible for leakage.

CJ

[ClenchedTeeth]

Thanks for the responses guys! I left it plugged in overnight and it now appears to be working perfectly, which I am very happy and very sad about. It even works when I switch it in/out and after I remove power for 5 minutes. I'll report back if it plays up again.

[ClenchedTeeth]

Oh, one more thing - what do you mean by the depth pot? This has pots for speed, width, delay time and regeneration, and internal trimpots for clock, bias and regen. I realise it's just a naming convention but it would help me know which knob to wiggle if it plays up again.

[George Giblet]

depth = width

When these go you lose the sweep/flanging effect. The audio signal will stay clean in both effect any bypass.

[ClenchedTeeth]

Ok great - thanks for that. Still seems to be working great, will keep you posted.