Roland Cube 40Xl

[basher106]

It's a step in the right direction. I couldn't see any electrical connection between the power amp & supplies and the processor so I'm not really surprised that the processor is still dead. So we had fried vias?... That's a worry. I'd expect the fuses to go first. Makes you wonder what went on here.

Anyway, have you tried the factory reset? If that doesn't work you need to take a close look at the processor. That's IC5 on page 20 of the schematic. With a meter and small sharp probes check the power pins for the correct voltages. Don't slip. I see +5, +3.3 and +1.5. (A special thanks here goes to the guy at Roland who chopped the schematic into such small sections you can't see what it going on. Nice one buddy.) Next check the reset line pin goes from low to high on power on with 'scope. Next check the oscillator is running at 16.9MHz on pins 139 & 140. Right after reset you should see activity on pins 79 and 80 ( i.e TP34 /35) as it fetches the code from external memory. If no activity on the data line (pin 80) then the program flash memory IC2 needs checking, but you should check it anyway for power. Also check if anything is running hotter than it should ( I maybe should have said that first).

Hi sorry for late reply, sadly been painting and other nightmare things!
just an update on what i've found from last testing ideas.

On IC5 All +3.3v +1.5v were present, but i couldn't find the +5v on schematic anywhere near IC5.

I managed to read the x1 crystal at a steady 16.9364mhz the schematic says value is 16.9344.

IC2 program flash memory chip has +3.3v on Pin 8 and pin 4 gnd


I'm not sure what I'm looking for on this next part!.. "Next check the reset line pin goes from low to high
on power on with 'scope". (So i grounded scope black clip to center 0v of psu on mainboard as in one of the pics.

So then i measured as best i could and took some photos of scope output on pin 79 it gives good signal (not sure if correct signal though!) but pin 80 looks very bad fuzzy distorted signal no matter how i set scope i took photos of scope from both pin 79 and 80 outputs.

[g1]

On IC5 All +3.3v +1.5v were present, but i couldn't find the +5v on schematic anywhere near IC5.

I don't see any either. I think he may have meant one of the 1.5V supplies.

The reset line is pin 81 (IC5). It may be easier to get your probe on to appropriate side of C48 or R14. You are looking for DC to go from 0 to 3V at power on.

[nickb]

I think I misread D+1.5V as 5V. No matter.

The signals on the program flash look reasonable. The point is there is something happening so the processor running.

Yes, confirm the reset is working. If that is OK take a look to see if the processor is sending commands to the LEDS on pins 5 & 6 of the panel connector CN201. While you are there look at the operation of the switch signals by pressing a switch and watching the signal to see if it changes. My thinking here is that stuck switches might stop the processor from running normally.

You can also look to see if there is activity on digital signals to the ADC/DAC IC7 i.e DA0, LRCLK, MCLK, BCLK, PDN_CODEC.

Frankly it's all a long shot in the dark as there is no other route available to us. Roland would just replace the entire board.

[basher106]

I don't see any either. I think he may have meant one of the 1.5V supplies.

The reset line is pin 81 (IC5). It may be easier to get your probe on to the appropriate side of C48 or R14. You are looking for DC to go from 0 to 3V at power on.

Ok thanks for that I've just checked and have a good 0v to 3v at power at pin 81 ic5 stays a 3v till i power off

[basher106]

I think I misread D+1.5V as 5V. No matter.

The signals on the program flash look reasonable. The point is there is something happening so the processor running.

Yes, confirm the reset is working. If that is OK take a look to see if the processor is sending commands to the LEDS on pins 5 & 6 of the panel connector CN201. While you are there look at the operation of the switch signals by pressing a switch and watching the signal to see if it changes. My thinking here is that stuck switches might stop the processor from running normally.

You can also look to see if there is activity on digital signals to the ADC/DAC IC7 i.e DA0, LRCLK, MCLK, BCLK, PDN_CODEC.

Frankly it's all a long shot in the dark as there is no other route available to us. Roland would just replace the entire board.

Hi Nick the reset is working OK it goes to +3v on scope from power on.

Pin 4 and 5 seem to be for led and clock data.
Here's my findings thanks for the help.

Pin 4 is led data 3.3V (no signal DC only)
pin 5 clock data 0.045v (no signal DC only)

Tested switches seem OK readings below.
Pin 6. 3.3v pressed power sq goes to 0v
Pin 7. 3.3v pressed play goes to 0v
Pin 8. 3.3v pressed tap goes to 0v (tap led dead)
Pin 9 3.3v pressed solo. goes to 0v
Pin 10 3.3v pressed CH goes to 0v
Pin 11 3.3v pressed. tuner. goes to 0v

IC7 from power on (All LEDs lit) on controls panel
no signals found on scope only DC

Pin 09 Dao. 3.3V
Pin 10 LRCLK. 3.3V
Pin 11 MCLK. 0V
Pin. 12 BCLK. 0V
Pin. 13 FDN CODEC. 0V


IC7 from power on (All LEDs unlit) control panel
No signals found on scope only DC

Pin 09 Dao. 3.3V no signals on scope
Pin 10 LRCLK. 0V
Pin 11 MCLK. 0V
Pin. 12 BCLK. 0V
Pin. 13 FDN CODEC. 0V

[nickb]

From this I would guess that the processor is getting so far and then getting stuck. Why that happens is anyone's guess. It could be bad flash prom, bad RAM, connections thereto or something else. Frankly, I'd say this is the end of the line. The only thing I have to offer is to check connections on the main board and especially solder joints under a microscope. You can see why this kind of board gets replaced in toto. Just ain't worth it.

PS: One WAG type thought this morning. If the clock and data to the flash program memory never stop I would guess that is where it's getting stuck. I'd expect it to load the code into RAM and then execute it. This might suggest a RAM issue where a counter or flag is corrupted.

[basher106]

Ok Nickb if there's anything else you or anyone can think of please give me a shout.

i've looked for roland spare parts i'm in the UK and I don't think there's much hope of ordering an amp module board from.them possibly through a music shop dealer but it'll probably be cheaper buying another amp.

Thanks anyway really appreciate it.

[nickb]

A Roland Parts dealer in UK. Name is Mark (Marco) 01803 292212