6 replies to this topic

[mdbradshaw]

I have a customer's CPC1100 in the shop, classic 16/27 errors.  He bought it used, it's never worked.

Various issues later...

 

I'm connecting to the BARE motor control board, it has power and nothing else connected.  I'm using a KNOWN, GOOD PC programming cable, connected to the PC Port.  So, no hand controller, no motors connected, no GPS, nothing.  Just me, a PC Port cable, MCUpdate and the motor board.

 

I was able to see and fix the AZM firmware, which solved the 16 error.  I cannot see or modify the ALT firmware.

    Device: ALT(DEC) Motor
    State: No Response
    Model: Unknown
    Address: 17
    Version: Unknown
    HwRev: Unknown

 

It's the HwRev (Hardware Revision) that is stopping me.  MCUpdate gives the error "[ALT(DEC) Motor] Hardware Revision doesn't match CEL file Hardware Revision"

 

The good working AZM side likes like this, for reference:

    Device: AZM(RA) Motor
    State: Running
    Model: CPC Series
    Address: 16
    Version: 5.23
    HwRev: 2

 

Have any of you guys done any deeper firmware work, or made custom firmware?  I need to force a "HwRev" value of 2 onto the chip, or force MCUpdate to ignore the Hardware Revision number.

 

It's also possible that the chip is fried, of course.

[mlord]

The two MCs are normally identical. So whatever hardware revision one has, will also apply to the other.

The firmware files themselves, with CFM at least, are text format and can be edited if need be.

But first just try using CFM (instead of MCUPDATE), via a Nexstar+ hand-controller. Celestron now intends that to work instead of MCUPDATE for all mounts, including older models.

If it also fails, then perhaps the MC itself has a real issue.

[mlord]

I believe the CPC series now shares the same MC board design as used in many other mounts, including the SE series, just with different firmware. NXW437 or similar? I could be mistaken here.

A T48 chip programmer (Amazon, AliExpress) can attach to the onboard headers for flashing/reflashing the MC PICs.

Edited by mlord, 15 May 2025 - 02:39 PM.

[mdbradshaw]

Connecting through a hand paddle and CFM was worthless, it won't even see the motor board and refuses to move forwards.

 

I examined some of the CEL files, they do have plaintext "Model" and "Hardware Revision" strings.  I made a copy of a CEL file, and tried various permutations of either commenting out those lines, or changing the string value to "Unknown" to match what MCUpdate was showing, to deleting the lines altogether.  MCUpdate warned me that doing this might be messy, but it let me proceed. It did fail upon trying to write the firmware, "MC not responding" or something like that.

 

I think the problem is that the chip is not even talking: "State: No Response" versus "State: Running" or, I think that one time I had "State: Boot Locked".  But at least those are responses.  This makes me think that the chip is dead, or not getting power.

[mlord]

Could you show a photo of the PCB, with the processor chip(s)? Mainly for my own benefit, so I can then perhaps suggest further actions?

[mdbradshaw]

Could you show a photo of the PCB, with the processor chip(s)? Mainly for my own benefit, so I can then perhaps suggest further actions?

I'm pretty sure that the chip is dead.  Under a microscope, there are signs that a previous owner attempted some soldering repairs (broken traces, jumper wire to pins, etc).  I think that someone smoked the board, tried to fix it, then sold the whole unit.  I couldn't even get the unit to power up properly until I swapped out a spare set of power/aux boards and disconnected the GPS. 

 

That being said, I have two dead NXW431 boards (CPC), and lots of spare NXW437 boards (AdvancedGT).  I have at least 2 chips that should be programed for the CPC, I'm going to try grafting them onto the 437 board.   The firmware updating software won't let you put CPC code on an AdvancedGT board, but I think that restriction might only be in the chips themselves.  The other microprocessors on the board seem to reference those chips as locations (16 and 17), the chips have some permanent register that defines their model name model number and hardware revision.  I think that putting CPC chips on any other of the motor control boards might allow CPC firmware to be uploaded. 

[mlord]

The NXW437 boards have a 6-pin programming header (or pads for one). 3-pins for each MC. The popular T48 programmers can attach to those and read/reflash chips at will.