CPC925 GPS mount problems

The_bluester (Paul) · #1 22-09-2012, 10:15 PM

Ok, some folks may have read it already, tonight I had the best chance I have had in ages to get the scope out.

Then as I was running through the alignment process, my 4yo son stuck something metallic in the PC port of the mount and it promptly failed. I now seem to have a multi thousand dollar door stop.

The hand controller gives the "initializing" display then goes blank and stays that way. The board in the base of the mount simply has a couple of ports on it, plus an RS232 chip and a buffer chip. It seems tha it is not talking to the motor control section, any ideas on fault finding?

The_bluester (Paul) · #2 23-09-2012, 09:44 AM

I am about to go and have a try at something, I am gong to desolder the RS232 chip from the board in case it has fried and an output has gone high or low and is stopping everything else from working. if it gets it going then the worst it is likely to mean that I have no PC interface via the mount (Which I have never used anyway)

If that does not work I will have to find a freight forwarding company to buy some bits from Celestron US, after what I hae seen about local costs for parts and knowing that the motor control board is $107 and the interface board $26 USD I would be pretty offended by the costs I have seen mentioned.

The other option would be to just remount it on the likes of an EQ5 and put up with the EP ending up in odd spots. For visual the alt az mount is hard to beat.

GrampianStars (Rob) · #3 23-09-2012, 11:54 AM

Try Here:-
http://tech.groups.yahoo.com/group/Celestron-CPC/

would be your best bet to help out with your problem

Poita (Peter) · #4 23-09-2012, 02:35 PM

I could take a look at the boards if you want.
Solder a socket in place of any chips you remove so that you can easily drop in replacements. Check the schematics for the chips and verify correct voltages at the pins. If no voltage or incorrect voltage, work your way back via the traces until you find the problem parts.

You should be able to look at the interface and look for what pins have power and where it would likely have shorted to, and follow those traces looking for failed parts.

The_bluester (Paul) · #5 23-09-2012, 04:36 PM

Hi Peter, are you able to test them reasonably easily? If so I might pull the MC board and I could send both that and the hand controller to you to check.

Biggest problem I have is time to look into it, I will have to get a chip socket for the RS232 chip and fit that and a new IC. The only other IC on that board looks like a buffer so I might replace that too.

I am considering remounting the OTA on a GEM, preferably a goto that has also got a straight clock drive function as well so i can cheat, or learn the sky properly. I am a bit tempted to stick it on a HEQ5 pro so I can do longer exposure AP with it than 15 second stuff.

The_bluester (Paul) · #6 23-09-2012, 11:21 PM

Well, it lives to fight another day. I removed the buffer/line driver IC from the interface board and it sprung back into life. It just has no PC interface or (probbably) guide port. Neither of which bother me.

The_bluester (Paul) · #7 24-09-2012, 08:00 AM

Wonder if we have any members in the US who might be prepared to buy the new circuit board for me and send it if I sent them the money.