CGX motherboard

[seanpius2020]

Hi,was wondering if anyone on SGL would know anything about motherboards.My CGX has stopped working and when I checked the motherboard there was a bit of smell the board was hot on one part which I have arrowed in picture, would anyone know where I could purchase  a replacement board, searched the internet with no luck.

[newbie alert]

Sorry for your misfortune, if its under 2 years old then send it back as its under warrenty , if not I'd unscrew it and see if you can see where it's burnt out..should be quite obvious 

Are you in the UK? Your local celestron dealer should be able to get one, but prepare yourself for quite a shock, David hinds were quite willing to sell me a handset for my cgem  but when it was apparent that it was the board, they wanted the whole mount back, posted via their retailer, but wasn't receiving anything at the time because of covid.. they couldn't/ wouldn't give me a rough price until they had seen the mount and assessed  it, but wouldn't take it in.. I offered to drop it off, they wasn't interested so I put a wanted add out for a board,  found one pretty cheap, and popped it in and it works fine..Totally lost my patients with celestron as I've had other issues with their products so I bought a ioptron.. the cgem now just sits in the corner.. Faith lost.. stuff them

[seanpius2020]

Hi,thanks for reply' i have the mount open and checked both sides of the board but there is no sign of burning but the board gets very hot where I have arrowed in picture also the led light on power button flashes on and off, i have the mount about 5 years, might just scrap it.What do you think about the ioptron I was thinking of getting the CEM70.

 

[malc-c]

I've managed to repair half a dozen Skywatcher motor boards, but they use easily programmed PICs and readily available firmware.  The part indicated is the main processor, and in a package that is not easily programmed by the hobbyist (assuming you can get the firmware

The part isn't listed on the Celestron website, so may well no longer be in production.  

[seanpius2020]

thanks Malcolm,i also searched Celestron and couldn't find anything,dosnt say much for the CGX if they have stopped producing them.

[newbie alert]

On 11/02/2021 at 23:27, seanpius2020 said:

Hi,thanks for reply' i have the mount open and checked both sides of the board but there is no sign of burning but the board gets very hot where I have arrowed in picture also the led light on power button flashes on and off, i have the mount about 5 years, might just scrap it.What do you think about the ioptron I was thinking of getting the CEM70.

 

I have a cem60, the cem 70 was about to be released but I be honest I thought it was way over priced( still do) at the time a cem 60 was £1699, the basic 70 was £2350 And the guider version £2550..  so for 10lb more payload I failed to see where the extra £650 was

But, the 60 has been awesome, streets ahead of the cgem, so much that I wouldn't consider celestron again

In your case, I'd look into getting your board repaired, replacement would be probably far too much money,  although a quick search throws up a mother board for a cge pro for £120 on ebay

https://m.ebay.co.uk/itm/Celestron-Motor-Control-Board-for-CGE-Pro-Series-Telescopes/233693802440?ul_ref=https://rover.ebay.com/rover/1/710-53481-19255-0/1?ff3=2&pub=5575376664&toolid=10044&campid=5338268676&customid=CjwKCAiA65iBBhB-EiwAW253W9FdmzVnsCBgASA50wgZkbRpCblCq3oUMTR6YQrHcAo8aWj_ic3WzhoCC8UQAvD_BwE&lgeo=1&item=233693802440&srcrot=710-53481-19255-0&rvr_id=2808755927949&rvr_ts=98ef37961770a9c532a76131ffea4125&_mwBanner=1&_rdt=1&ul_noapp=true&pageci=fcafbf59-760b-4a5d-9743-016fa1add184

[malc-c]

If you look at the two boards, the e-bay listing is not the same as the one in the OP. - The part number on the suspected faulty board refers to a CGX-L range - the listing is for a CGE Pro series.

I would check with the importers as to the availability and price of a replacement board before parting with £120 to a vendor on e-bay for a board that will most probably be totally incompatible, even if the connector blocks fit !

[Carbon Brush]

To start. I have little experience of Celestron mounts. No experience of this particular mount.
However, a potentially useful generic contribution on electronics problems.

If you can get a close up picture of the hot micro, with the part numbering legible, it will remove some of the speculation from replies.

But to the generic information.

If a micro gets excessively hot, certainly to the point of being smelly, or making you say ouch if you hold a fingertip on there, it is dead.
Reliability of micros is usually good and on the odd times they do fail (without external cause,) they generally just stop working, rather than become heaters.
It should (given sensible circuit design) be impossible to put a high voltage on a micro pin to destroy it.
This leaves the voltage regulator for the micro (3.3V or 5V usually) under immediate suspicion.
The first step is therefore to check the voltage regulator to avoid toasting a replacement micro.
If there is a voltage regulator failure (much easier to sort) this in turn raises the question of how the mount was powered (mains, battery)  and whether there might be something gone wrong here to damge the regulator.

That type of IC package is 'quad flat pack'. Squareish, flat and leads on all 4 sides. No imagination by the naming dept.
Removing the old device is possible if you have a small soldering iron and very fine wire cutters, or a dremel with cutting disc.
Basically you cut the leads off the package, get that out of the way, then deal with the pins one at a time.
If you don't do it for a living and try to desolder the complete device, you will probably damage the (very thin) PCB traces.
The professional way uses what looks like a thick wall square copper tube on the end of a big soldering iron or hot air source. Very expensive.

If you get a new micro, it has to be programmed. First you need the software that Mr.Celestron puts in there. Next you need a programmer.
Until the micro is identified, you don't know what programmer is needed. Maybe cheap, maybe you know someone who has one, maybe expensive.
Next how to connect? The programming pins may be brought to pads or pins on the board. I can't tell from the photo. If so, you make up a lead.
If not, you need a jig to hold and power the micro for programming. Big money.

Sorry this is not pointing you to a solution. But if you attempt repair, or obtain a replacement board, it may help to avoid another toasted circuit.
Also if you are offered a solution that sounds too good to be true, you are in a better position to assess it.

Having said all of this, you never know. The next post may be from someone who has a garage full of Celestron mounts, or who has repaired dozens and knows them inside out.

[malc-c]

Can't say I have experience with Celestron mounts, but have repaired around half a dozen Skywatcher mainboard for fellow SGL members by reprogramming the PIC micros with the SW firmware, and that was easy compared to this board as SW used 16F chips.  The firmware files that SW use need converting to hex and some additional work done on the configuration bits.  Not tried looking for the binary firmware file for this mount, but if its available then the same process should work to convert the file to HEX.  Removing and replacing the chip is the easy part, as you say, just cut the legs as they enter the package and then desolder the legs from the board.  However for me programming the replacement would be an issue as I don't have a board / adapter that accepts that package.

I agree, if a micro gets hot it tends to be toast.  If nothing has been plugged into the board incorrectly (as in the case of the previous SW board repairs) then it would suggest a failure in another component which lead to the micro failure, and I agree with the above post that voltage regulation, or possibly failed inductor may have caused an overvoltage.

@seanpius2020 can you post up a close up of the processor, or post up the identity / part number and maybe we can see if this board can be repaired 

[malc-c]

OK I had to download the Celestron utility which then downloaded all the firmware packages to the installation folder... but there are two files  CGXL_BOOT_3.1.9120.cfm and CGXL_APP_7.17.0031.cfm   Now I'm wondering if the BOOT file is the bootloader, which if it is then that could be burnt to the micro and then the updater application used to squirt the firmware to the PIC (SW code is one file with the bootloader included in that one single file).  I'll see if the binary can be converted, but then we would need to know the micro used before removing any config bits etc

[malc-c]

Firmware file has been converted  

Just need to ID the chip (zooming in on the image above its just a blurr) and see if my PIC programmer supports the device, and then find a way of programming it !

Edited February 13, 2021 by malc-c
added results of zooming on image

[malc-c]

Damm.... I found an image on a cloudynights forum about changing the RTC battery and could make out it's a MK20DX256 - which is an ARM Cortex processor, which my PICKit2 doesn't support

[malc-c]

Well it looks to be a no go.... Having checked out the J-Link programmer and the QFN64 adaptor board to accept the processor for programming, the cost would be over £120 by the time you add in the cost of the chip.  Regretfully I wouldn't be programming enough of these devices to warrant that investment

[seanpius2020]

Thank you all for your replies.

[Mick J]

Good work @malc-c,  stay with us.