127 SLT No Response 16 error

[linker33]

I have a 127 SLT Nextstar+ that recently developed a No Response 16 error.  Pressing the Back button allows the Alt to work, however the Azimuth doesn't.  

Version under utilities shows the following:

HC: NXS .31.9200

MC: ?.??    5.18

 

There seems to be only one MC chip, with both motors testing continuity to it.  On MCupdate, it is recognizing the ALT motor, but not the Azimuth.  I have tried updating the MC board to all available options on MCupdate, and all fail connecting.   Updating with CFM goes through with no issue.

 

I reflowed all connections on both boards in the mount, and tested continuity on the cable.

Did factory reset by pressing 0 when starting.

Input voltage is fine

Swapped the ALT and AZ motor connections to eliminate a motor issue.

 

Any other suggestions?

 

 

 

 

 

 

[CCD-Freak]

With the CGE series mounts "No Response error 16" indicated no signal from the encoder.  It was usually a cable issue. 

Don't know if this applies for your mount but it might be something to check.

 

 

[newbie alert]

No response 16 refers to the RA ( azimuth).. celestron say that it's the hand controller has lost communication to the motor control board

Have you checked the board for possible damage? It maybe very slight 

There might be some fuses on the board, on my AVX they were fb1 -4

On my cgem ( which uses nexstar* handset) you can plug the HC into the aux port just incase the hc port has damage... don't plug it into the guide port ( if it has one)thou, this will certainly cause damage

 

[Cosmic Geoff]

I have had this error twice with the same mount - a SLT Nexstar+ - and fixed it by reloading the mount firmware using the Celestron utilities.  Clearly the problem I had was corrupt firmware.  I found a utility that actually tested the firmware, which confirmed that corruption of the memories was present.

[newbie alert]

35 minutes ago, Cosmic Geoff said:

I have had this error twice with the same mount - a SLT Nexstar+ - and fixed it by reloading the mount firmware using the Celestron utilities.  Clearly the problem I had was corrupt firmware.  I found a utility that actually tested the firmware, which confirmed that corruption of the memories was present.

He's suggested that the cfm ( celestron firmware manager) goes through without issue

[malc-c]

Can't really offer much advice as I'm not familiar with Celestrons, but having repaired several blown SW motor boards though I would give my 2p worth.

The no response message on a handset would suggest the issue is with communications between it and the mount.  However, if you can run a firmware manager / uploader which presumably connects form the PC to the mount via the handset, and this reports no errors, then this would suggest that the cabling and indeed the microcontroller are fine.  The confusing factor is that if the same arrangement then has an issue uploading the firmware to the microcontroller then it brings into question exactly how does the firmware manager check the communications. Which one is giving the false positive.

On SW boards (other then the newer ARM processor based ones) two PICs are used, with their UARTs connected via two blocking diodes, and sometimes these have blown and thus the serial comms fails.  Other times, the failure of these diodes have lead to blown UARTs on the PICs and both PICs needed replacing with pre-programmed new ones.  Now not having worked on Celestron boards I can't say if this is the case here, nor what would be the likely cause.  More experienced users have suggested it may be an encoder error.  The fault could be at the decoder itself, or if the microcontroller is blown then it won't be processing or detecting the decoder.

I've never tried hacking a celestron firmware, but as its just a binary file it should be no different to the process outlined in the long thread here  the only issue you may have is the availability of the micro controller.  The 16F886's used in most of the SW goto boards now have a 22 month lead time, or you pay 6x the going rate from some rip of merchant on e-bay