⟐ Answer accepted April 21, 2026 at 4:51 MST

I am troubleshooting a professional coffee machine (Melitta C35) control board based on the Freescale ColdFire MCF5232CVM100 (BGA package). The system is currently stuck at the initial "Please wait" screen and does not proceed to the main menu.

Hardware Details & Measurements:

·         MCU: MCF5232CVM100 (ColdFire V2 Core).

·         Flash: cFeon EN29LV160 (TSOP-48).

·         Power Rails:

o    VDD (Core): Measured 1.6V on the micro-capacitors surrounding the MCF5232.

o    VDDIO/Periphery: Stable 3.3V found across the board.

o    Analog/Other: 5V rail is present.

·         RTC Battery: Measured 3.29V (stable).

·         Debug Interfaces: The board provides a standard 26-pin ColdFire BDM header AND a 10-pin (2x5) Mini-BDM connector.

·         Service Port: External 9-pin RS-232 (DCE, Female).

Symptoms:

1.    On power-up, the display initializes and shows "Please wait".

2.    The board has a Reset button that toggles the 3.3V line, but the MCU remains in the same "Please wait" state after reset.

3.    I measured -5.6V on the TX pin of the RS-232 port, which indicates that the line driver is powered and the UART is likely initialized by the bootloader.

Questions for the community:

1.    Given that the display shows "Please wait", is it safe to assume the MCU has successfully initialized the FlexBus and started executing code from the external Flash?

2.    What are the typical reasons for a ColdFire V2 to hang at this stage? Could it be a checksum mismatch in the Flash or a timeout waiting for a peripheral (I2C/SPI)?

3.    Does the presence of both 10-pin and 26-pin BDM headers imply any specific debugging priority? Is one more suitable for a USBDM interface to dump the cFeon Flash?

4.    Are there any known "trap" states or Double Bus Fault indicators I can check via the BDM pins without a full debugger?

Thank you, Alex

⟐ Answered April 20, 2026 at 4:05 MST

edit

I managed to get it working but it’s started again. It grinds, sounds like it producing coffee, but no coffee is produced, water is in the tray and underneath the unit with very wet grounds in the bin. I’ve tried changing the grounds finer and courser. I’ve tried using ready ground coffee it’s doing the same. I’m googled eyed with googling for answers.

⟐ Commented April 16, 2026 at 9:27 MST

⟐ Commented December 28, 2025 at 0:59 MST

I found mentions of the motor not being properly aligned.

The official FAQ states: The motor might not be in the correct position. Check if the water tank is filled and if the drip tray is in place. Turn the appliance OFF and then ON again. Then simultaneously press the button for My-Coffee and the on/off button for more than 2 seconds. The motor will move into the correct position. Insert the brewing unit again and check that it is correctly locked in position.

However, this proposed solution did not reset the motor position in my case.

I found that the locking handle of the brewing unit moves a metal lever.

This metal lever engages a button in the machine.

By carefully pressing this button (i used the handle of a small spoon), the motor reset to the correct position.

Long story short: I don't have a question, and just wanted to post this here for future reference.

⟐ Commented November 04, 2025 at 7:48 MST

Thank you - Rowan

⟐ Commented October 31, 2025 at 7:23 MST

⟐ Commented October 21, 2025 at 4:16 MST

Recently, the machine has been repeatedly indicating that I should refill beans, but this is filled with beans. I changed the beans and wiped out the container, grinder inside of machine but the problem persists.

Or when Refill beans is on the screen and we press the button to do coffee it did it few times

We tried to soak the brewing block just in water for a,few,hours, we can get 1-2 cups of coffee after that and the issue starts again.

What is interesting when we put in a ground coffee it works without any problems.

What could be the cause?

I would be very grateful about tips: what seems to be problem or who can fix it?

⟐ Answered October 02, 2025 at 6:39 MST

Was working perfectly until a few days ago when the 'Air in the system' icon appeared on the display. I checked the manual and pressed the bean button (coffee strength) to purge air from the system.

The pump runs for about a minute and when the process completes, the icon remains illuminated. I followed this same procedure multiple times but the drip tray just fills with clean water.

I read a post somewhere online that said a likely (and common) culprit was a failed drainage valve.

After following the iFixit guide, I thoroughly cleaned the main unit and looked for any failed/ broken parts. Everything looked fine.

I replaced the drainage valve with a new Melitta part, lubricating all of the valve gaskets and the white plastic actuator in the back of the brewing unit area with a light coat of silicone grease. The actuator was installed using the markings on the cover as advised in the guide. No cables were disconnected or damaged.

Upon reassembly and after a factory reset, the same issue persists.

I've also followed the iFixit guide to dismantle and thoroughly clean the brewing unit and see if a gasket had failed or if there was a blockage. There wasn't - everything looked fine.

Can anyone help?

———

ADDITIONAL INFO:

Unit is regularly cleaned with Melitta products and has been descaled with Durgol descaler.

With the brewing module side cover off, the startup/ shutdown procedures seems to still move the parts of the brewing module.

Spoke to the Melitta engineer at Coffee Classics (UK) and he's suggested that I replace the flow meter.

The engineer has speculated that if replacing the flow meter doesn't resolve the issue, it could be the logic board which would make the unit uneconomical to repair.

Success! It was the flow meter. Now drinking my favourite brew again.

⟐ Commented July 30, 2025 at 9:17 MST

Any ideas??

I removed the brewing unit for the weekly cleaning. It went out, but not very easily (it does so more often).

After cleaning and rinsing the unit, I went to reinsert it again. Unfortunately it doesn't slide in anymore .

It feels like it's stuck in the middle part, where the motor pin (with three slots) resides. The outer sides of the brewing unit do have some moving space, the middle hasn't. When I observe it closely, it seems to be in place with the brewing units three pins.

Pushing it by force can slide it a bit more, but I didn't dare to go fully. Removing it after this exercise was only possible by helping it slide by pressing outward from the inside in the tray area.

Anyone a solution for this?

I'll add pictures of the inside and the brewing unit. .

Images added

⟐ Commented July 08, 2025 at 6:45 MST

⟐ Answer accepted May 21, 2025 at 17:09 MST

⟐ Answered April 19, 2025 at 5:02 MST

Thank you - Rowan

⟐ Answered March 16, 2025 at 8:09 MST

⟐ Answered January 14, 2025 at 10:57 MST

⟐ Commented January 05, 2025 at 2:40 MST

How to work around the problem with uninterruptable descaling program? Every time I turn on the machine it restores yourself to the 2nd/3rd phase of the program. Tried several ways already:

• "Reset to default settings" using Power and Steam buttons
• Unplugging the machine and keeping this way for 24 hours

⟐ Edited by author September 18, 2024 at 11:30 MST

Any advice on how to fix this issue would be much appreciated

⟐ Answered August 29, 2024 at 8:53 MST

⟐ Answered June 07, 2024 at 0:42 MST