Any ideas on repairing a (slightly!) blown motor board ?

[jafonseca]

Hi I have a AZ GOTO mount and i think the PCB board broke , is a 'Synta MC001 Rev. C' the synscan can conect with motors , says this message  ´'Both axes ... No response'  It's possible to repair it?

Thansks. Sorry for my english

[malc-c]

I'll drop you a direct message later when I have more time.. but it should be repairable.

[malc-c]

It's not just mount motor boards that I've been asked to see if can repair.  I'm sure the member won't mind me posting this, but somehow his Skywatcher wi-fi dongle produced some of that magic smoke and stopped working.  When the hood was popped it was clear that some component had taking a disliking to whatever the user had done.

A bit of research and it seems that it is a voltage regulator that takes 12v in from the mount and drops it to 3.3v that the wi-fi chip uses.  Anyway, the item was posted to me and I ordered up some 3.3v regulators.

Once the board was received I did a quick test to make sure I could find area's on the board that gave access to 12v, 3.3v and ground so I could solder three short wires to.  I was in luck and so the 3.3v (1 amp) regulator was CA'd  to the board with a small heat sink to the tab

To test the board I connected a short length if an old cat5 cable to the dongle, and the once I had identified the  12v, GND, TX and RX lines hooked it up to my breadboard which has a couple of programmed 16F886's on it and powered it on.

Phone found the access point and the Synscan app was downloaded to my phone and everything all connected.  I was able to run alignment routines etc.

 

the regulator was warm seeing how much voltage it had to deal with, but not excessively, so the case was put back together and a few days later the forum member got their dongle back, which I am told has been working fine ever since 

Around the same time a new member to the forum contacted me as they had used a cable from Amazon to connect the handset to their fairly new EQ6 that they had purchased second hand and now the mount is dead.  Fortunately the handset still worked when he connected it to his EQ5 synsacn unit, but on inspection the EQ6 control board has suffered some damage around the connector for the D9 socket

 

Anyway, with Christmas fast approaching he purchased one of the refurbish boards rather then send his one to me to see if I can repair it, and then send it back if successful.  Two days later the replacement was fitted and the member is now back up und running.  Once all the festivities are over he will be sending me the damaged board for me to have a look at.  If I can't repair it then I have a board that can donate parts if required for future repairs.

I asked what cable he got and he forwarded a link to a product on Amazon.  It turned out to be a serial to RJ11 cable used  to configure router and network switches via their console port. It's a simple enough mistake to make at to the untrained eye it looks like a straight version of the curly handset cable.  Either way I told him to bin the cable and provided links to the correct EQDIR cable.   

So that's another mount that has a new lease of life.  It's strange though that the last three repairs have all be EQ6's 

Anyway, that's two members back up and running.  

[Paul M]

I've followed this thread from the very beginning, Malcolm, and I'm still impressed with your skill and inginuity.

I've done quite a lot of electronics in the past but not digital and not SMD. Well I did a bit of a hack on my brother's game box thing, back in the day for him. I had components floating away in a sea of solder.. 😳

As an increasingly clumsy NEQ6 owner, I suspect I'll be needing your services, eventually

 

[malc-c]

I had better reserve one of the refurbished EQ6 boards then, just in case 

There are guys out there who are far more capable of fixing electronics than I am.  Seeing a guy re-ball the main processor on a 4060 GPU graphics card certainly makes my fixies look crude ! - But then the goal is to get these things working again, and if the fix looks a tad Heath Robinson it doesn't matter - no one other than me and the owner will know its there !!

Thanks for the praise... I've had a few boards that were not fixable, but it wasn't for the sake of trying...

[Trickysystems]

I  thought I'd add my experiences with my SW Flextube 250P Dob with Synscan MC004F mainboards. I decided to add my own WiFi adapter and used the wrong pin data and blew both boards. Used a PICKit 3 to program them but still no joy with the 'Both Axes no response' messages. Changed the motor drivers then, plus the other chips for good measure. I also added the pins to enable on board programming of the PIC. Some measure of success with no error about the AZ motor, just the ALT motor. A good look under the magnifier revealed some not great soldered joints on that board, which was the one I started on. Back into the scope, hand controller says all good, but still no action from either motor. Hmmm, more thinking and reading. I was using the Hex file, MC004Final with config bits 3FFA 0700 set. I then tried code MC004D with config bits 2FA2 0500 set, no code or data protection. Back into the Dob and I heard a slight click from the motors as I powered on. Answered the hand controller startup questions and tried the direction control buttons. You beaut, all working again. Now if the current wet weather will stop for a time and we get clear skies...  I've just recently moved to a rural region about 80 kms South from Sydney (Australia) with great dark skies, so should be good to test all functions.

Thanks to this Forum and especially malc-c, for his and all the others who have contributed information and solutions for these less than robust boards.

[malc-c]

Glad to hear this thread helped get your Dob back up and running.  

[Trickysystems]

Hi all,

Just a few thoughts.  While there has been success with repairing failed boards, ( thanks again Malcolm et al) the newer boards use ARM STM32F051 and other chips and the MC006 uses a PIC18F45K20, the old MC004 seems to be no longer available as a spare. The last code available for the earlier boards seems to  be 2.09 as later code versions are too big to fit the PIC16F886 memory, unless I am missing something and the SW firmware loader figures out the processor and loads correct code for it.  Another thought I have is that while my Dob 250 has servo motors, do the latest SW Dobsonians now have steppers or still have DC servo motors?  From pictures on the net of later motherboards, they have DIP switches and ARM processors, plus embedded WiFi, but there is no information if these can be fitted to earlier Dobsonians for any possible upgrade path for earlier scopes with toasted motherboards, hence the stepper or servo question.

While I have a Dob, is there enough information to compile a matrix of what motherboards go with which telescope (EQ, AZ, Bob etc), and the latest code version? This may be of use to the people who have boards that are not repairable, or seeking an upgrade path.

Richard

[malc-c]

Richard, you have basically summed up why this post is now 15 pages long, and why it all started.

The OP found out three / four year ago that his motorboard(s) were basically obsolete as Skywatcher had change the design of their goto Dob mount and there was no upgrade path that didn't involve buttering the existing housings, hence the need to try and repair the original boards.  This upgrade has continued with other motorboards, migrating away from PIC based processors to STM32 based ARM processors.  I have no idea why as there is no real need for more processing power, so can only assume it was down to something else such as product availability, or just a means to make repairing them harder (the reverse engineering of  the PIC based EQ6 board was done quite some time back so it's not a new thing).  The process of repairing the newer board would be much the same, however soldering the 64pin package is not so easy, and then you have to program the chip via ICSP.  I personally haven't seen a new ARM based board in person, so can comment on whether the newer board has more protection against reverse polarity, and shoving 12v up the RX line by using the wrong cable. 

With regards to the stepper / servo question, the output stages of these boards are basically two H bridges, so could be used to drive either through the PWM (or more correctly PPM).

As to the file size, I'm not sure where in the process the file size expands.  It may be that the cause is where empty spaces are padded out with zeros, I don't know.  If you ignore the warning and proceed the code uploads and verifies OK and doesn't seem to affect the performance or functionality of the mount.

For me personally I've looked at what's available to program the newer ARM based boards, but would need to invest in a better solder station and possibly a microscope given how fine the pitch of the pins are.  But I'm guessing there are plenty of PIC based boards still in use that will keep me busy...

[IDM]

I have recently had an issue with the control board from my Skywatcher EQ6R mount and have managed to successfully repair the board by replacing a damaged Q3. I detailed the identification and replacement of Q3 in this thread:

I have ended up with about 50 spare transistors which I am holding in stock and can happily provide these to anyone who has the same issue. If you cannot do the fix and do not or cannot find someone who can do the soldering, I would be happy to assist as long as you understand any work I do is at your risk, I don't of course want any payment. I also know there are others who are probably more competent than me in doing the work, in particular @malc-c.

Hope this is helpful.

Happy New Year

Ian  

[malc-c]

Ian, I've just posted a reply on your main thread, but this is excellent news.  I really do like to hear that people have fixed a damaged board and managed to get their mounts back up and running for little outlay

[MikeAa]

Nice repair work malc-c!

[mimmo]

Good evening, unfortunately my engine card eq6 black upgrade goto neq6

no longer works. it gives me the error BOTH AXIS NO RESPONSE. I would like to point out that when detecting voltage signals from port 232 on the mount I created a short, producing a spark. Unfortunately it doesn't work from here. I tried to redo some soldering, but nothing. I'm wondering if anyone has any tips. From the photos you can see that no components are burnt. Thank you mimmo

 

Edited January 22 by mimmo

[MikeAa]

Not familiar with an EQ6 mount, but what is port 232?

[mimmo]

3 hours ago, MikeAa said:

Non ho familiarità con la montatura EQ6, ma cos'è la porta 232?

Com rs232 

[malc-c]

Just to clarify the port on an EQ6 / NEQ6 that has a D9 port does not run the serial lines at true serial voltages.  The TX and RX lines are TTL level, 0 to 5v.  The problem is that next to the data lines there is +12v and GND so what you have probably done is basically shoved 12v across the data lines and blown the EUART port of both PIC micro controllers.

The only way to fix this is to follow the steps in this thread to program two new 16F886 microcontrollers, desolder the existing ones, being carful not to lift any pads and damage the tracks, and then solder the newly programmed microcontrollers in their place.  Prior to Christmas I could have sold you a mainboard that already had the repair undertaken as I had several spares due to other members kindly donating blown boards to me after they had already gone out and purchased a new replacement control board.  However I no longer have any as they have all gone.

The other problem is that as you are in Italy the cost of shipping the faulty board for repair will be expensive as it needs to be insured and tracked.  Due to issues I've had with sending replacement micro controllers  and a control board outside of the UK I can only take in boards for members based in the UK mainland.

Replacing the microcontrollers isn't that difficult, but unless you have or can find someone with a PIC programmer who can program them for you it's pointless to try.   The HEX code for an EQ6 has been attached (assuming the forum software allows that).  

If a repair is not possible then the only alternative is to replace the old board with a new one.  If you do choose that option, then please consider donating the faulty board to the exchange program and send it to me by the cheapest postal service (no need to send it insured or tracked as its faulty anyway, should it get lost in transit).

EQ6-NCP.hex

[MikeAa]

Thanks for explaining malc-c! Totally unrelated but I used to travel to Milan for work sometimes. Love the place!! Good luck with the repair.

[mimmo]

9 hours ago, malc-c said:

Giusto per chiarire che la porta su un EQ6/NEQ6 che ha una porta D9 non fa funzionare le linee seriali a tensioni seriali reali. Le linee TX e RX sono di livello TTL, da 0 a 5v. Il problema è che accanto alle linee dati ci sono +12v e GND, quindi quello che probabilmente hai fatto è stato sostanzialmente inserire 12v attraverso le linee dati e far saltare la porta EUART di entrambi i microcontrollori PIC.

L'unico modo per risolvere questo problema è seguire i passaggi di questo thread per programmare due nuovi microcontrollori 16F886, dissaldare quelli esistenti, facendo attenzione a non sollevare alcun pad e danneggiare le piste, e quindi saldare i microcontrollori appena programmati al loro posto. Prima di Natale avrei potuto venderti una scheda madre che era già stata riparata poiché avevo diversi pezzi di ricambio perché altri membri mi hanno gentilmente donato schede bruciate dopo che erano già usciti e avevano acquistato una nuova scheda di controllo sostitutiva. Comunque non ne ho più perché se ne sono andati tutti.

L'altro problema è che, essendo in Italia, il costo di spedizione della scheda difettosa per la riparazione sarà elevato in quanto deve essere assicurato e tracciato. A causa dei problemi che ho avuto con l'invio di microcontrollori sostitutivi e di una scheda di controllo al di fuori del Regno Unito, posso accogliere solo schede per membri con sede nel Regno Unito continentale.

Sostituire i microcontrollori non è così difficile, ma a meno che tu non abbia o trovi qualcuno con un programmatore PIC che possa programmarli per te è inutile provarci. È stato allegato il codice HEX per un EQ6 (supponendo che il software del forum lo consenta).  

Se la riparazione non è possibile, l'unica alternativa è sostituire la vecchia scheda con una nuova. Se scegli questa opzione, considera la possibilità di donare la scheda difettosa al programma di scambio e inviarmela tramite il servizio postale più economico (non è necessario inviarla assicurata o tracciata poiché è comunque difettosa, nel caso in cui si perdesse durante il trasporto).

EQ6-NCP.hex 46,5KB · 1 scaricamento

Hi, Malc-c thanks for your reply, I downloaded the ex code, I'll give it a try with a repair shop for amateur radio equipment located here in Milan. Let's hope they have the equipment and can do it. if not, I will purchase the mc015 board. very kind, thank you Mimmo

[malc-c]

PIC Programmers are very cheap, the adapter to hold the SOIC packaged PIC is typically $30+ plus shipping.  Ebay would be the best place to look for a PICKit2 or PICKit3 programmer and adapter.  But then you could be spending 40+ euro on something you would probably only use once, and it would be better to put that money towards a new board if the repair shop is unable to help.  Another option is to contact a local school or college to see if they have the hardware and could help you out, either as an electronics club if they teach electronics.

[malc-c]

11 hours ago, MikeAa said:

Thanks for explaining malc-c! Totally unrelated but I used to travel to Milan for work sometimes. Love the place!! Good luck with the repair.

I used to work for Epson around 25 years back and my job involved European travel.  Their Italian office was based in Milan and I agree with you, it's a very nice place, especially if you eat where the locals eat rather than the tourist area's... Fantastic pasta dishes and lovely bars that were open well into the small ours of the morning  :-)

 

[mimmo]

22 hours ago, malc-c said:

I programmatori PIC sono molto economici, l'adattatore per contenere il PIC in package SOIC costa in genere $ 30+ più spese di spedizione. Ebay sarebbe il posto migliore per cercare un programmatore e un adattatore PICKit2 o PICKit3. Ma in questo caso potresti spendere più di 40 euro per qualcosa che probabilmente utilizzeresti solo una volta, e sarebbe meglio investire quei soldi in una nuova scheda se l'officina di riparazione non è in grado di aiutarti. Un'altra opzione è contattare una scuola o un'università locale per vedere se hanno l'hardware e potrebbero aiutarti, sia come club di elettronica se insegnano elettronica.

Many thanks

[malc-c]

Another bitter sweet success today.

I received a synscan from an EQ5, along with a handset and cable from a fellow SGL member today.  The handset was displaying the normal "No response both axis" message so it was a case of replacing the PIC with a new one having first programmed it with new firmware.  I downloaded the latest 2.7.02 firmware and converted the binary into a HEX file and uploaded the code to a new 16F886.  It was then that I thought I would document the process of replacing a PIC if all you have is a soldering iron and don't have access to a hot air solder station, as I get asked about this so many times.  So here are a series of images to best help explain the procedure.

The first thing to do is to cut the body of the old PIC away from the legs soldered to the PCB.  You can use a mini drill with a small cutting disk, or use a small file to separate the legs at the point where they enter the package.  Once you have done that the body should drop away, leaving the legs in place

Apply some flux to the pads where the legs are attached. I use Amtech flux, which whilst being expensive is very good at what it does.  Then with the iron set to 350c, you'll find the legs will easily come away when the iron is applied.

Once all the legs are removed a liberal application of Isopropanol Alcohol IPA (99.99%) and a wipe with a piece of kitchen towel cleans the board up and removes the residue flux.

Place the newly programmed PIC on he PCB and when you are happy with the placement, solder pins 1 and 15 (or 28 and 14 - so long as they are diagonally opposed) to hold the PIC in place.  Then apply some more flux to the pins and after tinning the soldering iron start soldering each leg in turn.  The flux will ensure the solder flows well and makes a good joint.

Once all the legs are soldered give the board another spray of Isopropanol Alcohol IPA to remove the residue of flux and and that's it... Job done!

Now it's just  case of testing, and for that I use a specially written application which sends off a load of commands to interrogate the mount and log the response it received back.

This confirmed the repair was a success.

However when the board was tested with the handset I still got the same "no response " message, so further investigation was needed and upon removing the rear casing of the handset I got a whiff of burnt electronics and upon inspection found a hole burnt into the daughterboard, which sadly wasn't repairable.

So there you go... I hope this step by step guide is useful.  However if you do have a faulty board, are based in the UK and still feel this is out of your comfort zone then drop me a PM and we'll sort out getting the board sent to me for repair

Edited January 24 by malc-c
duplicate images

[MikeAa]

Nice job! Now I have to ask: what was burnt on the handset?

[malc-c]

1 hour ago, MikeAa said:

Nice job! Now I have to ask: what was burnt on the handset?

 

A Ferrite bead - Which looking at this thread  seems to be one of the two Achilles heals  

[Trickysystems]

Just a few observations to go with Malcolm's detailed post.

While I do have a hot air rework station, due to the small size of these boards with surface mounted components very close to the ICs, I've found the Dremel method works best for me. Once the body of the IC is removed, a quick wipe with a soldering iron and solder wick cleans the pads nicely. Tin the bottom of the IC legs, and a wipe of a flux pen on the board pads, position the IC and solder away. There is usually enough solder on the legs of the IC and the board to attach the ICs, however use a good magnifier to check and correct where needed.  If the ICSP pins aren't present on the control board, install them. I found them helpful with my two failed MC004 boards to check programming and to also reprogram the PICs. I have a PICKit 3, so just plugged my repaired board in, applied power to it, and placed  the PIC programmer into the correct mode. I had my config bits incorrectly set for the boards, so the ICSP pins made it easy to correct. My motor drive ICs were also toast, so if it is a good blowup, they usually will show discolouring on the surface of the chip. I was fitting my own wifi adapter and applied 12 volts where it shouldn't go. There are discrepancies with the actual pin outs for the various GoTo implementations.  I've just acquired a Saxon 150/75 GoTo which is almost the same as the SW Star Discovery 2i. It had been modified by a 2 year old, so had the controller cable was destroyed, finder scope disassembled and only one eyepiece. Check the hand controller? Simple, just plug the cable from my Dob in, NO! Checked the wiring and it was different. If I'd plugged in the other cable, then I'd be trying to fix a new board, probably ARM based. I'll have to check what it is some day. The wiring gods were with me, so crimped on new connectors to the cable remains and it worked. Upgraded motor controller and handset software to the latest versions.  I now have two operational GoTo scopes, one 6" and one 10", and living in a rural area, with Bortle 2 skies, I'm amazed at what is visible compared to when I lived near a city on the coast.  This thread has been invaluable to get me and others up and running. I wonder how many have plugged in the wrong cables, rather than a genuine component failure? I do like the quality of the board repairs that Malcolm has posted, first class!

Richard