chaotic-one

On 08/11/2021 at 16:28, malc-c said:

If that didn't work, take a look at the 1N4148 diodes on the TX lines of the PICs - If replacing those (see previous posts in this thread where I replaced some using through hole parts) you still get the "no response" message on the handset, or a time out using EQMOD and a EQDIR cable then yes I would agree, the UARTs on one or both 16F886's will have been blown, and replacing them with a reprogrammed PIC would be my recommendation.  Hopefully you'll have more luck than I have at sourcing replacements at non inflated prices due to the global shortage.  I had to resort to contacting Microchip in order to get the last pair of controllers, which took 6 weeks to get to me from the UK.

The RJ11 port is a normal standard serial (RS232) port.  The TX/RX pins are given as 

 

Note that you will need a standard RS232 to USB adapter if your computer lacks an old style serial port - If you use a 5v TTL serial to USB adapter it may not work as the handset is expecting +/- 12v rather than 0-5 signals

A little googling found the pinouts for the Skywatcher serial cable that normally gets shipped with the mount

 

More info

Thanks for all the info Malcom

wrong post

On 04/11/2021 at 08:08, chaotic-one said:

Thanks for the input, wifi dongle was in and out when powered up a few times. My donor board has more ferrite beads, so will try your suggestion later.

On 04/11/2021 at 18:50, malc-c said:

Not really advisable to unplug and plug in things whist the mount is powered up to be honest... need to get in to the practice of park and power off when switching handsets and mounts 

lets hope swapping the ferrite beads resolves the problem

Okay replaced the ferrite beads, still no go, looks like I lost the programming on the chip maybe

Thanks for the input, wifi dongle was in and out when powered up a few times. My donor board has more ferrite beads, so will try your suggestion later.

On 18/10/2021 at 09:52, malc-c said:

Excellent.... nice easy fix !

Well Malcolm,

I putting the blame on you with your comment "nice easy fix". All was working fine until we tried to marry Asiair Pro to Synscan wifi adapter. On plugging in the "old" handheld it showed a message that it could not communicate with AR or AZ, making me think I have a new problem.

Any thoughts

If the sky clears tonight, we may try our first photos.

On 13/10/2021 at 16:08, malc-c said:

I'll drop you a PM

Hi Malcolm and everyone else,

So as an WISP, we have plenty of old circuit boards laying around from radios we have built or that failed. On Friday I went painstakingly through the junk and found a board with labels F1, F2, F3, F4 on it. Pulled out the soldering iron yesterday and pulled off one of those "f-ing things" and installed it on my broken motherboard.

LAST NIGHT WE HAD OUR FIRST LIGHT ON OUR NEW-TO-US 16" DOBSONIAN.

Saw fuzzy Andromeda, looked at the moon, Pleiades, etc. It was a long night, cloudy and all.

NOW to spend the real money on eye-pieces. Thanks everyone.

9 hours ago, malc-c said:

MC004 is for a Dob mount. 

L3 an L4  are small surface mount ferrite beads that form a filter with two capacitors, possibly C8 and C9.  They are possibly BLM31PG500SN1L (or equivalent)  with the following spec:,

1206 [3216 Metric], 50 ohm, 3.5 A, EMIFIL BLM31P Series, 0.015 ohm

Available form most online suppliers (but most are affected by shortages due to CV19)

Having repaired several SW motor boards you may find that then two 16F886's have blown as well depending what you did to damage the board.  If you replace L1 / L2 and still get a "no response both axis" then you'll need to replace the PICs and have them programmed. as covered in this thread

EDIT - On HEQ5 / EQ6 boards L3 and L4 are Ferrite Beads - on the MC003 Schematic I have (similar to a MC004 for a Dobsonian) L4 is shown as an inductor....with no component value.  It connects pins 1 and 4 of the link cable connector to ground.  

Thanks Malcolm, was a long read and interesting, most of which I had forgotten when I was re-qualifying myself as a computer tech in Canada. Yes it is an Orion 16in dobsonian which had just bought. Are you still repairing these boards, if I send you our broken one?

8 minutes ago, AbsolutelyN said:

Not much info to go on but suggest you look here:
https://www.firstlightoptics.com/search/for/mother+board/

I've also had good experience from contacting Skywatcher direct but you'll need to give them much more info such as which product... 

http://www.opticalvision.co.uk/contact_ovl.html 

 

Thanks for the quick answer, but they do not have the synta mc004 board in stock (I saw a 4month delivery timeline from Skywatcher. I am looking for the actual component at the L4 location on the motherboard

Hi,

Just "smoked" a component right off the Board (Don't know how). anyone know where I could get a replacement component or what it is Please?