DanEcho really quiet but still getting power. I'm talking whisper quiet.

[tombaker]

Hi,
I have a DanEcho that I bought second hand 4 years ago. It ran fine when I bought it, it hasn't had a tonne of use since then and it's only played one gig with me.
I recently joined a new band, took it to our 4th rehearsal it worked fine, then I packed it up, went home and returned to the gig venue two hours later and the pedal wasn't working properly.

The pedal is getting power as indicated by the red engaged LED. Which shows the switch seems to be functioning fine. The input and output jacks seem to be still intact and I tested continuity from a 1/4" cable into the input jack and onto the circuit board and it was fine.

None of the capacitors seems to be leaking, although I'm only going by what I looked up on google images for leaking electrolytic capacitors.

I couldn't see any lifted traces on the PCBs or any broken components.

My continuity testing only went so far as some of the traces are hard to follow on the double sided board.

When I listen really carefully I can hear the signal which is the dry and delayed signal. All the pots are still working fine.

I can't figure out why the signal isn't being passed at the correct level and why it would happen so suddenly, e.g. within a two hour period of it not being used.

Any help would be appreciated, thanks.

[Jdansti]

This is a long shot because I'd think that Danelectro would have dealt with this, but the PT2399 can "lock up" if the pot connected to pin 6 is set at too low of a resistance when the chip is powered up. There's probably a resistor in series with the pot to prevent this situation, but a quick and easy check would be to disconnect the power supply if you're using one and disconnect the guitar cable from the input jack which would disconnect the battery, turn the delay time pot to somewhere in the middle of its travel, and reconnect the power. If this doesn't help, your problem lies elsewhere. 

[tombaker]

Tried it, but to no avail.
Just curious why the signal would be struggling to get through. It does say that the pedal was manufactured in 1996, it could be a failed capacitor but I lack the proper meter to check them on the board.

[tombaker]

Although now the pedal has a lot of hissssss, either when engaged or bypassed.

[Jdansti]

Unfortunately, Danelectro is pretty tight with its schematics, although I found that the Danecho uses a PT2395 instead of a PT2399. The only other thing I can suggest would be to verify the ground continuity between the rings of the input and output jacks and to verify that you've got a good 9v from your supply or battery.

[tombaker]

You are correct, it is the PT2395.

I can hear the delay working, it's just at an ultra low level, which shows that the PT2395 is still working, at least at some level.

I took out the pcb's last night and cleaned them under the magnifying glass and couldn't turn up any loose traces.

I've continuity tested grounds for both the in and out jacks and they're connected to the pcb fine. The more information I could find on the characteristics the pedal was displaying (hiss, low level volume) the more it points to either the IC's and transistors needing to be replaced or all the capacitors needing to be replaced.
The capacitors wouldn't be too much hassle to replace but the IC's would and I'm tossing up whether it's worth the time to replace these things with the possibility that it still may not work.

As for power, I get the same results out of the pedal when I'm using either 9v battery or a power supply and the ring connection on the input jack traces fine to the battery on the pcb so I don't believe that power is an issue.

[Jdansti]

These things can be frustrating. Before you replace anything, you might want to turn on the soldering iron and re-flow the solder joints on the boards and any off-board components. I would stay away from any surface mount joints, at least on the initial pass.  If you have any "pot cleaner" it might be worth spraying some in the pots and working them back and forth.  Let them dry out before applying power.

[tombaker]

Cheers i'll try resoldering.
Would WD40 suffice as pot cleaner?

[Jdansti]

I would not use WD40. I would only use electronic contact cleaner designed for pots. Your next best bet is to work the pots back and forth a lot while playing to see if you hear any major change in volume or noise. This will usually identify a dirty pot.

[Ben N]

I am reading this thread with interest, because what you describe is exactly what happened to my dear old Dan Echo--which I think I may still have in storage somewhere, and which was my fave delay until it went whispery. I always assumed it was the IO board, or maybe a short to ground somewhere--maybe a toasted cap? It would be a good idea to go through it with a signal probe, but it's hard to know what to expect without a schematic.

[tombaker]

I tried resoldering the main ground points and the pot connections

I used jumper cables to bypass the main board and there was no hiss and the signal was passing fine so it's definitely something on the main board.

[Jdansti]

Dang!  The only other thing I can think of would be to get voltage readings for all of the pins on the ICs and post them with the hope that with the help of data sheets, we can figure out if one of them is bad, or if they are getting the proper voltages and have the proper ground connections.

Well, one more thing: I'm not sure how reliable this is while the caps are on the board, but you can check the continuity across the electrolytics and look for a shorts. I'd discharge the caps with a piece of wire first (low voltage/current, so no danger) and then with your meter set to 10k ohms or greater, place the + meter lead on the + cap lead and the neg meter lead on the neg cap lead. If you show very low resistance, you've got a bad cap.

[tombaker]

Sorry for the belated reply,
I did voltage readings for all 5 ICs

pt2395 - 3.8V
LM311N - 3.8V
RC4558P - 3.8V
TC4013BP - 3.8V
HM50256P - 3.74V

So they're all getting power.
As for the caps, it's hard to know whether some of them aren't showing a reading due to the multimeter leads not being able to make a good connection, but I'm getting readings for some and none for others.
I've just finished a project and am in between projects so it could be worth recapping all the electrolytics, at this point I don't really have anything to lose except time and a small amount of change from my pocket.

[Jdansti]

Good point!

[tombaker]

But much appreciated for your help. Atleast I know more about the pedal I had been using for a while.
I'm going to start building the echo base pedal as a replacement, so that should be fun, while I figure this out.

[fretzburner]

Check coupling caps,might be the problem.

[tombaker]

Can I check them with a DDM?
That is the only piece of proper testing equipment I have.
I want to reiterate that there is still signal present and that the delay chip is still working and all of the pots as well. But it's just quiet with a lot of hiss, not hum, hiss.

Can I test it with an audio signal and measure the AC voltage using the DDM? Just to test whether or not signal is passing through it?