Please Help Me Diagnose My Fly Deluxe

[essgee]

Hello!

I bought a 1999 Fly Deluxe that is in great physical condition, but the electronics are not what I expect.

1. With the stereo/mono switch in mono, and using a mono cable, I get no sounds at all.

2. With the stereo/mono switch in stereo and using a mono cable, I get great magnetic sounds, but no piezo.

3. With the stereo/mono switch in stereo and using a stereo cable, I can get sounds from both the magnetics and piezo, but they have very little volume. The magnetics sound about 20% of the volume for scenario 2 above.

I have done a bunch of other testing, but the results haven't been repeatable. The above is the current state of affairs.

Generally speaking, the electronics look fine (no obvious damage or corrosion). The master volume has just a tiny bit of scratchy sounds at the top of its range, the battery tests fine, and the switch for magnetic pickups seems to be functioning as designed.

Thank you for any help!

[vjmanzo]

Hi @essgee—these sorts of issues are best approached by isolating the variables (of course), so let’s consider the following points—this is my assessment only:

-the cable you’re using; is it a quality brand with a US-made jack at the end?
-flex Flex PCB; if it’s torn anywhere then things will not work properly
-the Fishman Powerchip; less likely to break, but possible for it to be damaged or underpowered, so check the battery connector and use a Duracell or Energizer battery
-the output jack; less likely to be broken, but it happens
-the switches and toggles; likely to break and need replacing
-the red switch; not likely to break

Can you start by trying to make things work with a high-quality cable plugged directly into your amp? And the proceed by examining the two Flex PCBs on the interior of the instrument for any tears?

[essgee]

I replaced the battery with a new Duracell (9.55 VDC), and tested the voltage in the control cavity and it measured the same - ruling out some possible battery connection issues.

My cables are of good quality and all have been tested via multimeter.

The flex PCB looks new to my eyes.

The piezo balance control is fully CW.

With the new battery, there is now signal when using a mono cable in mono mode, but it's not great news:

Code: Select all

| Pickup System Switch | Magnetics Response        | Piezo Response                                   | 
| Magnetics            | Magnetics at 50% output   | Some response when hitting the strings very hard |
| Combination          | Magnetics at 30% output   | Some response when hitting the strings very hard |
| Piezo                | Magnetics at 20% output   | Some response when hitting the strings very hard |

[essgee]

Update after testing with just a good cable and an amp.

With Mono Cable in Mono Mode:

• Magnetic pickups are heard in all three mag/piezo switch combinations. Loudest when the switch is in Mag-only mode, and quietest when in Piezo-only mode, but always present. The mag pickup output is attenuated.
• Piezo pickups are not audible, but signal is present in all three mag/piezo switch combinations. (if I crank my amp to 10 I can barely hear something).
• The very small piezo output is unaffected by the piezo volume control. That is to say, the volume change from Off to full volume is the same, and cannot be turned off. I suspect that this is considered "no output" but some tiny signal is leaking out.

With Stereo Cable in Stereo Mode, Magnetic side:

• Magnetic pickups are heard in the Mag-Only and Blended mag/piezo switch combinations. The pickup output is still attenuated, but not as bad.
• No Piezo output is detected.

With Stereo Cable in Stereo Mode, Piezo side:

• Magnetic pickups are heard in the Combination and Piezo-only mag/piezo switch combinations.
• The piezo pickups are still barely audible in the Combination position, but when cranking the amp to 10 the result is louder than with the mono cable.
• In piezo-only mode, the piezos are at their loudest (I only have to crank the amp to 8 to hear them...), but you only hear them over the magnetic pickups if you turn the magnetic pickups all the way down.

The magnetic pickups sound the best (at full output) when I use a mono cable in stereo mode with the mag/piezo switch set to mag-only.

There is no combination of switches or cables that yields anything close to usable piezo output.

TLDR:
The magnetic pickups are present almost everywhere, but at reduced output.
The piezo pickups are not sending any real output, but some signal leaks out.

[vjmanzo]

Have you checked/adjusted the small trim pot on the Fishman preamp board? This should increase the level of the piezo output.

[essgee]

Have you checked/adjusted the small trim pot on the Fishman preamp board? This should increase the level of the piezo output.

I have. The results I've posted so far are with the trim pot fully CW (maximum).

I did some testing to see what difference it makes in the signal. I was able to measure about 3dB difference between fully CCW and fully CW. Both are essentially inaudible.

Thank you so much for your questions and hints!

[vjmanzo]

Gotcha!

Okay—then let’s keep checking toggles, pots, Flex PCB, and the jack. But before we do that, what strings are you using (brand and gauge)? A very rare scenario, but some strings have ball ends that, when coupled with the bridge, interrupt the signal flow of the piezos.

[essgee]

That is interesting about the strings!

I'm using DR Veritas 9-42. I had the same symptoms with a previous set of strings that were (I'm pretty sure) D'Addario 9-42.

How do I conclusively check the output jack? I'm trying hard not to desolder anything unless I absolutely have to.

I'm having problems with testing switches also. For example, I've tested the mag/piezo switch by measuring the resistance between the connectors on the rear of the switch while changing the switch positions. I really expected to find zero ohm reads across some of the terminals, but never got that.

Thanks again for your help!

[Floydwhammy]

You could test the output jack by attaching wires on the back tabs of the jack before the signal goes through the jack but you may have to clear some of the plastic heat shrink covering the tabs to get to them. Or easier if your confident follow the wires backwards from the output switch to the tabs on the switches they connect to. one should go to the battery one goes to ground and the other 2 are the mono and stereo leads. so you can attach one wire to the ground area and one wire to the mono lead to test the mono signal and then again one wire to ground and one wire to stereo lead to test stereo signal. If you have an old guitar cable around you can cut off one end and just use that end for testing. The center cable inside will be your signa (positive) and the wire mesh around the outside (shielding) will be your ground. Attach this end to the guitar cavity and plug the other end with the 1/4" guitar jack still on it into your amp or headphone practice unit or whatever you play your guitar through, If the guitar comes through like it should with either cable and ground connection setup then you will know your output jack needs to be replaced.