Rocktron Rampage R80 - No Sound problem

[paolone]

Hy to all of you

My Rocktron Rampage R80 sounds quite well, but sometime if i switch it off and then i switch it on it doesn’t sound anymore my guitar.

I hear the the normal knoch when i switch it on
If i insert the footswitch i heard the speaker noises
If i pump up the  master volume i hear the presence in the speaker

What can be?

I saw the two green capacitors in the pre amp section... can they be the cause?

Do you have the electric schematic of this amp please?

Who can help me please?

Thanks

Paolo

[paolone]

Hy

I send you the photo of the 2 mainboard of the R80 amp

Now, after one hour of sleep the amp is working...
I don’ t know why.

Some more information:
The sound, for an 80watt amp is very low, with the master pot set to half the volume is normal (with my fender mustang 2 - 40watt - with the master pot sert to 1/4, the volume is higher...)
The reverb pot don’t change anything in the sound if i set it to 0 or to 10.
The volume is quite double in the distorsion mode respect than in clear mode. There is too much difference...

Let me know if someone of you have the electric schematic, please

Thanks

Paolo

[dmeek]

Please post photos of the foil side of the 2 boards and another of the power amp board with the ribbon cable moved to the side.

[paolone]

Hy

Thanks for the interesting.

Here is the photos of the 2 sides of the power board
And the photos of the Accutronics reverb

Paolo

[paolone]

Hy

Here is the pre pcb front and rear

Problem are:
- after some hours of use (random), if you switch it off to make a pause and than you switch it on, there is no sound of my guitar.

- if you wait some hours (random), than it works but there are the problem listed below (THIS PROBLEM THERE ARE ALWAYS, Also on the first switch on):
- no reverb even if you turn up or down the reverb pot
- low volume level in clear mode, better volume ievel in distorsion mode

[dmeek]

Plug a cord from Effects Send to Effects Return and see if it works. It could be the Effects Return jack switch.

[phatt]

Plug a cord from Effects Send to Effects Return and see if it works. It could be the Effects Return jack switch.

Dmeek beat me to it,, Yep FX loop is the most likely culprit. they are *Switching sockets* the switch terminals corrode and give the symptoms you are describing. 
Also looks like it may have a Preamp out and Poweramp input,, which is another fail point. link them as well.

As to reverb not working,,pull the RCA plugs and clean the pins.
Also flip the tank and use a DMM to check you have continuity of the little transducers,, there are 2 of them. if no reading look close for broken wires.

As for the big difference in Volume between clean and dirty,, well that is how most of them work,, Normal.
Phil.

[dmeek]

Here is a rough schematic of the preamp output. Another possibility for the reverb is the input and output jacks might be reversed.

[paolone]

Hy

Thanks to all of you.

@dmeek  I've just make a test with a cord between effect send-return, The sound is more noisily.

@Phatt  I have test the reverb box (Accutronics 1EB2C1A) with a multimeter:
IN = 57 ohm
OUT = 196 ohm
Reading the instruction in the pdf i think it's ok...

@dmeek  the cord that starts from the board pin "IN" goes to the reverb box pin "OUT" (cord colour: RED). Impedance misured from cord pin 100 ohm
the cord that starts from the board pin "OUT" goes to the reverb box pin "IN" (cord colour WHITE). Impedance misured from cord pin -LO-


I have cleaned the 2 boards and the terminals with the electronic components cleaning spry.
Do i have to use the sand paper?

Now that i have all the boards unmounted, do i have something other to do before to remount and test them? (check capacitors...)

Thanks
 
Paolo

[dmeek]

The wire from CN2 IN on the preamp board is the reverb send. It plugs into IN on the reverb unit. OUT goes to CN3

[paolone]

Ok,
Thanks for the clarification.

This night i mount all the board and test the amp

Tomorrow i will tell you if it’s OK.

Thanks

Paolo

[paolone]

Thanks to all of you

The amp is still working. Let’s see in the next week...


REVERB IS NOT WORKING.
Is like if the reverb pot is broken, (I have test the impedance of the reverb tank and it was good).

How can i test the board and the pot with a multimeter please?

Thanks

Paolo

[dmeek]

Connect a wire on the board like this. It will bypass the reverb pot.

[paolone]

Hy

I have tested the resistance of the pot with a multimeter (red sonda on the center pin, black sonda on the lateral pin, in both the way)
It shows 0 to 44,8 kohm turning the pot from a side to the other
The pot is ok
There something else to check please?

Wich is the way on the board of the electric current from the reverb pot to the reverb tank and the continue?

Thanks

Paolo

[dmeek]

The reverb pot is after the output of the reverb unit.
If you hit the reverb unit do you hear the springs rattling through the speaker?
Unplug the 2 RCA plugs, set reverb pot and master on 10, touch the tips with your finger. One will cause hum in the speaker. That one goes to the OUT jack
Check the voltage on IC 11 pin 1. Should be 0V
Make sure nothing is plugged in the footswitch jack. If the ring connection is shorted to ground it will cut the reverb.