Bypassing Peavey Tubefex DSP / turning it analogue

[Enzo]

Ah, yep there they are on the relays.


I can sorta read it, it is after all really just a computer. Your input goes right into an ADC, which results in a serial data stream. The same ADC takes the FX return. That puts it in the digital domain. Now you have the CPU and its RAM and ROM, and those communicate with the DSP chip. A lot of this thing is tied up in interface, the rotary encoders and LEDs, the switches, MIDI, memory card, control, and housekeeping, and of course, the DACs, which turn it all back into analog for your ears.

[MarkusBass]

Markus, did you look at that schematic set closely? I sure as hell don't see it as simple.

Yes, I looked at the schematic. It looks very close to one of the latest TC Electronics bass amps - all digital (which I was fixing). When I said that "this is not so difficult", I was talking about desoldering the 132-pin chip (I was answering to Fragger post). I wasn't talking about fixing the amp in general. You, most probably, understood something else.
Until in the amp there are no vaporized tracks/components, and you have the schematic, fixing it is still possible. Especially, that you can buy this obsolete chip. But it is not easy; it requires having a signal generator, an osciloscope and a lot of knowledge about digital circuits (including DSP). Still, having all this is not impossible.

Mark

[Enzo]

Assuming THAT chip is what it needs, but there are other LSIs in there as well. I have every confidence in the Peavey team, and I suspect the "cannot repair" diagnosis wasn't based on not being able to figure it out, I'd wager on inability to source a part. Just as they no longer have transformers for Classic 20 or pull-switch volume controls for CS800..


Yes, unsoldering and replacing the IC is not dificult. I was thinking that diagnosing the problem would be anything but trivial even for an experienced tech, and certainly over the head of a novice.

[MarkusBass]

Taking into account that OP said:

That should be easy enough.

the whole task may be quite difficult for him. It does not look like he has required tools and knowledge. But who knows?

Mark

[fridolin66]

Hi all,

I have a TubeFex with the typical battery problem. Can someone please send the schematics to ckgreve@gmx.de? I need to be sure that I fixed all the damage that the battery did before I think about switching to no-bat mod. The link above does not work :-(

Thank you very much,
Kai

[Enzo]

Peavey has them and will send them off if you request from customer service. You might try Peavey-Europe first, but if they can't help, contact the main factory.

[Jazz P Bass]

Peavey Tube FX Schematic

Here is a reposted, resized schematic.

[Jessedude]

hi!
is there a possibilty you could repost that schematic? my tubefex stopped working, we think it is part of the power supply becuase it just humms and it seems the whole input section is stopped functioning..

[Jazz P Bass]

The schematic in Post #22 is a valid file.

http://music-electronics-forum.com/a...76-tubefex.pdf

[Jessedude]

The schematic in Post #22 is a valid file.

http://music-electronics-forum.com/a...76-tubefex.pdf

thank you!
It has been awhile and I sent this to 2 techs and one didn't want to touch it and the other one couldn't find the problem with the machine. It powers up but the input stage is bypassed. I reset the memory and all that,I can access the presets, but no sound.It has the battery mod, and is the 1.5 version.

What is also strange is that the pregain and eq lights are all off and when I pass by the global presets I can access the eq stage but not the pre-gain, it says it is BYPASSED.
Something is not working right, I am in Quebec canada, should I send it to Peavey or just ask another tech to to take a try at it.

[Jazz P Bass]

I would send it off to Peavey.

Also, contact then first.