I spent a great bit of time on the phone this afternoon with Garry Ingle of meademods on the subject of my woes, and decided I'd try here as well to gain a double-forked approach to solving this dilemma I am having. The more minds, experience, and wisdom the merrier, right?
Here's the backstory...
A couple months back, I had been hired to fix an ailing Meade LX200 Classic whose tantalum capacitor on the power panel PCB went and turned into a thermine bomb. Fortunately, it didnt do any damage to any nearby components, so, I'd removed the 6uF 25V capacitor which was the culprit and replaced it with a 10uF 50V electrolytic. I did this to the main PCB and hand controller as well.
To ensure functionality, I'd swapped all of the hardware out of my own 10-inch LX200 with the hardware I had been hired to repair (a local guy hired me through a Facebook group, I don't offer those services here nor do I advertise them anywhere), and after a night of testing all worked out well...
...until it came time for him to reassemble his own scope. He had found that his was not working correctly after I had fixed it (I'd done this many times with great success, and this was the first failure for me), so after a week of discussing the issue I agreed to look at his entire scope instead of just the electronics bits... This was to iron out any issues, and to test it against my own identical scope just to see if there were issues not present at the first try.
On his end, his scope will not post. Upon power-up, the MEADE text appears in the hand controller display then a random string of characters appears, followed by inaction from both the RA and DEC drives. In short, the hand controller freezes at the MEADE display and that's it. Nothing. Nada... Well, except for a lot of heat from the heat sink in the base, but that's about it.
Compounding issues is that with his telescope, in addition to the original Meade controller, also came supplied with the Clearline Tech aftermarket hand controller. When that hand controller is used on his scope, a "COMM ERR" readout happens followed by the same inaction of the drive motors and inability to slew the scope. On a side note, Clearline is sending a replacement hand controller because it literally melted in the heat of an intense heatwave we experienced here in the Pacific Northwest - great customer service on their end!
On my end...
My 10" LX200, which I've had the last seven and a half years, is failing in its own right. It had been a couple months since my scope had last been powered on. The last time it had been powered, it worked perfectly and all functions were present. The only two times I have ever had an electronics failure of this scope was when I had reversed polarity of the power cord at a star party in Goldendale back in 2015, and when I'd popped the power panel fuse in it when I was attempting to fix the blown capacitor from that previous issue.
At issue, is that on my scope, I have immediate DEC motor runaway whenever the power switch is turned on. All connections look to be okay at both RA and DEC motor drive boards, and both drive boards seem to be somewhat pristine. The main PCB in the base looks to be perfectly okay as well. The capacitors on my scope (both hand controller and base) were replaced with 10uF 50V electrolytics years ago).
I cannot recall ever hot-plugging anything and my hand controller is minty inside.
What could be causing these issues?
Mind you, I don't have access to an oscilloscope nor do I have acce$$ (<-- see what I did there?) to fancy calibration equipment.
Edited by SteveRosenow, 29 June 2021 - 09:44 PM.