Crate Flexwave 120/212 combo strange sounds popping sounds

[blindboybenton]

Hello all
we in the uk don't see many of these.. This amp works ok but after 10 seconds from switch on , a popping sound happens every 4-6 seconds or so. When it happens the tuner led display is pulses with it
It happens on all channels

All effects are working
and all channels working too
had a look for a schematic, But in the version i saw there is no info on the effects board,

I'm thinking of changing the SMD electrolytic caps on the effects board.
But i don't have them all and with my eyes not looking forward to it
Have used a heat gun and freezer spray, but makes no change.


Many thanks BBB

[shortcircuit]

have you tried looking for an arch in the dark

[g1]

Does it do it using CD input? I think that is after the DSP board.

[blindboybenton]

When i connect aux in it still hear the popping though the speaker. at switch on its ok for 20-30 secs then starts Tuner works but as soon as the popping sound starts 4 of the leds light up and tuner don't work. and the effects stop working. Im going start to change a few of the electrolytic caps and see . BBB

[J M Fahey]

Please donīt start swapping electrolytics (or anything else) at random.
And SMD capacitors at that

It happens on all channels

What does this mean? How do you know? Have you scoped all channels?

Please at least do some troubleshooting first:

If you hear it through the speaker then you must see it on a scope,so start scoping speaker out ... what do you see?
Then start going backwards, there must be one point where you donīt see the popping any more, then you concentrate there.

Do you have a schematic? Or can get one from Loud?

[Jazz P Bass]

Here are the documents that I have for the 120H.

FlexWave120H.zip

[blindboybenton]

Hi. I have removed the fx board the popping sound goes away. If you remove the tuner display the popping goes away. Once the popping sound starts all effects stop. The amp is functional on all channels without popping sound if the effects board is removed. Im sure the cause is the fx board. I have the schematic. . I'm going to scope the outputs/ inputs of the fx board tomorrow to confirm. Thanks bbb

[J M Fahey]

Ok, if problem affects both DSP effects and tuner , I guess only common link between them is their power supply:
Do they both run out of some 5V supply?

Scope the +5V line ... or whatever feeds them.

I have the schematic.

But we donīt, and you are asking here, so please upload it.

[g1]

I think he was referring to the schematic posted in post #6. None of the available schematics (that I've seen) have the DSP board though.