AutoStar 497 - need help please!

[ChrisM]

Just before I travelled to a large astro-education event (where I was one of half a dozen demonstrators) I somewhat absent mindedly thought that I'd better check the battery in the hand controller of my Meade LX90.

I removed the 4 screws to take off the back cover and found that there was no battery in the hand controller, which is an Autostar 497.

I put the back cover back on and travelled 1.5 hours to the astro-ed session and then found that my scope didn't work anymore. Darn!!! I had to manually track objects by loosening the clutches every couple of minutes...

Symptoms: Switch on and there is the customary 'beep'.
The keypad and the display on the hand controller are fully lit up. This is abnormal. There is no information displayed, or if it is, it's not visible because the display is fully lit up, so masking any alphanumeric characters.

There is nothing obviously out of place or wrong with the circuit board, so now I don't know which way to proceed.

Any help would be most appreciated please.

Thanks, Chris

[PhilTas (Phil)]

Hello Chris,

your photo of the front of the Autostar shows the GO TO button is pushed in.
If this button is engaged it is probably enough to stop the Autostar from booting.

Try disassembly again and re-seat the button membrane .

Also the display ribbon cable is a little crooked in the socket. Release the cable by pushing the black locking slide towards the cable. This will loosen the cable so you can seat it properly. Then push the slide back in. Push it evenly on both sides.

I suggest you try these singularly. Try the button membrane first. Then if it doesn't work then reseat the ribbon cable.

Let us know how you go.

Cheers Phil

[iborg (Philip)]

Hi Chris

All the buttons should protrude above the surface, have a look at the photo.

Also, I've sent you a PM.

Philip

[ChrisM]

Originally Posted by PhilTas

Hello Chris,

your photo of the front of the Autostar shows the GO TO button is pushed in.
If this button is engaged it is probably enough to stop the Autostar from booting.

Try disassembly again and re-seat the button membrane .

Also the display ribbon cable is a little crooked in the socket. Release the cable by pushing the black locking slide towards the cable. This will loosen the cable so you can seat it properly. Then push the slide back in. Push it evenly on both sides.

I suggest you try these singularly. Try the button membrane first. Then if it doesn't work then reseat the ribbon cable.

Let us know how you go.

Cheers Phil

Hello Phil,
Thanks for your suggestions.
For the photo of the keypad, I had not properly reassembled the hand controller so that is why the buttons were sitting low. When assembled correctly, they all sit well proud and used to function reliably.

I tried reseating the ribbon cable in its clamp/header. I suspect it might be the problem because the cable has started to delaminate and I'm not even sure that each track is continuous.

I took it out then reinserted it, reassembled then tested - twice. Neither test was successful, however after one test I could get the scope to respond to the Alt/Az keys and change the speed in the normal way. However there was still no text on the display, so I was operating blind.

Cheers, Chris

[ChrisM]

Originally Posted by iborg

Hi Chris

All the buttons should protrude above the surface, have a look at the photo.

Also, I've sent you a PM.

Philip

Hi Philip,
Thanks for your reply.
As I mentioned to Phil, the buttons were low only because I had not reassembled it properly when I took that photo.

I'm played around with the ribbon cable, which I suspect might be the culprit. I don't know whether I can replace it because it seems integral with the display.

BTW, I didn't receive a PM from you.

Cheers, Chris

[KG8]

Originally Posted by ChrisM

I'm played around with the ribbon cable, which I suspect might be the culprit. I don't know whether I can replace it because it seems integral with the display.

I'd back right off until you have more knowledge on this Chris. Opening the controller was unnecessary, as you found out, and tampering with the ribbon cable is definitely not something you want to do lightly. With lack of clear directions I would be considering shipping it off to an astro shop etc. But have a look at the cable and sockets, perhaps there is a fault there? A look with a magnifying glass or shots with a macro lens, look for bent pins etc (but don't try and tinker!).


Plug and play astronomical gear is one thing but electronic repair is a whole other ball game believe me.

[ChrisM]

Originally Posted by KG8

I'd back right off until you have more knowledge on this Chris. Opening the controller was unnecessary, as you found out, and tampering with the ribbon cable is definitely not something you want to do lightly. With lack of clear directions I would be considering shipping it off to an astro shop etc. But have a look at the cable and sockets, perhaps there is a fault there? A look with a magnifying glass or shots with a macro lens, look for bent pins etc (but don't try and tinker!).


Plug and play astronomical gear is one thing but electronic repair is a whole other ball game believe me.

Thanks for your thoughts and caution. The plastic ribbon cable had a Z-shaped fold in it which I think might have stressed it. I acted on advice received and have good follow-up action in hand. As far as tampering goes, I have been constructing and playing with electronic circuits for over 50 years so it's not just a recent thing!

Cheers!