13 replies to this topic

[jamtime]

I recently unpacked my 10" Meade LX200 Classic after being mothballed for 10-12 years. As soon as I got it set up and turned it on, I'm on A/C by the way, I got the infamous puff of smoke  behind the control panel and it was dead. Now I'm going to preface this by saying I'm an extreme novice, not an electrician or an electrical engineer. Soldering speaker wires pushes the limit of my repair capabilities. So, everything I tried as a resolution going forward was by perusing the vast knowledgebase and expertise of this forum, and a few others. So here's how I've proceeded. I found out the initial problem was because of bad caps on the power panel pc board, and finding out ClearLine Tech sold replacements, that's the route I took. When I received the new board, I did the replacement, and after replacing the battery and fuse, I got the unit powered up and it immediately began slewing the R/A, which I was not expecting and because of that, I had a potential cable pinch approaching so I turned the unit off. I was not looking at the handset at that time, so I have no idea what the display said. I adjusted the cable and powered the unit back up and then nothing happened. The ammeter showed 2 bars, the handset displayed Meade, blinked 4 times and then nothing else happened. I then replaced the battery and fuse again, turned the unit back on and nothing changed. Next step, I unplugged and plugged back the power panel pc board, the DEC motor cable, both ends, even reversed the ends, the back side DEC cable to the board, the handset cable, opened the DEC cover and did the same thing to the 6 pin connector on the DEC motor board. I then bought another handset from Clearline. When I plugged that in, new cable by the ay, and powered up the unit, I got nothing different. 2 bars on the ammeter and the Clearline display on the handset. So, I guess it's not likely it's a handset problem? I thought I could try to see if I could get my laptop to control the scope through AutoStar, I have ver 5.53,  but I'm having Com issues and can't get it to connect, so that's not an option right now. In any event, are there any other troubleshooting things for a neophyte like me to try other than going for a new DEC motor encoder board? I realize that replacing that board requires some soldering, but I'm invested now! Thanks in advance.

[RichA]

The LX200 electronics were sensitive to electro-static discharge.  More than a few people cooked their motherboards for the Meade ED refractors when they tried to put them into the mounts, just by touching them.  The R.A. slew issue was a known problem back then.  I had a 16 inch LX200 do it on me.  Also, wall plug power supplies can bite dust with age too, losing amperage without displaying any voltage loss.  Electrolytic caps in the motherboard and control panel can both go bad, it's one of the main problems with all electronics of age, not just Meade scopes.  You could get it tested by an electronics repair person, you can buy component testers and test everything (resistors, caps, inductors, etc) systematically. 

 

A good in-circuit unit (Huntron, Heathkit, Data vu) will run $300 or a lot more, but this one is cheap:

 

https://www.ebay.com...:Bk9SR_j95cTIYg

[Skywatchr]

I recently unpacked my 10" Meade LX200 Classic after being mothballed for 10-12 years. As soon as I got it set up and turned it on, I'm on A/C by the way, I got the infamous puff of smoke  behind the control panel and it was dead. Now I'm going to preface this by saying I'm an extreme novice, not an electrician or an electrical engineer. Soldering speaker wires pushes the limit of my repair capabilities. So, everything I tried as a resolution going forward was by perusing the vast knowledgebase and expertise of this forum, and a few others. So here's how I've proceeded. I found out the initial problem was because of bad caps on the power panel pc board, and finding out ClearLine Tech sold replacements, that's the route I took. When I received the new board, I did the replacement, and after replacing the battery and fuse, I got the unit powered up and it immediately began slewing the R/A, which I was not expecting and because of that, I had a potential cable pinch approaching so I turned the unit off. I was not looking at the handset at that time, so I have no idea what the display said. I adjusted the cable and powered the unit back up and then nothing happened. The ammeter showed 2 bars, the handset displayed Meade, blinked 4 times and then nothing else happened. I then replaced the battery and fuse again, turned the unit back on and nothing changed. Next step, I unplugged and plugged back the power panel pc board, the DEC motor cable, both ends, even reversed the ends, the back side DEC cable to the board, the handset cable, opened the DEC cover and did the same thing to the 6 pin connector on the DEC motor board. I then bought another handset from Clearline. When I plugged that in, new cable by the ay, and powered up the unit, I got nothing different. 2 bars on the ammeter and the Clearline display on the handset. So, I guess it's not likely it's a handset problem? I thought I could try to see if I could get my laptop to control the scope through AutoStar, I have ver 5.53,  but I'm having Com issues and can't get it to connect, so that's not an option right now. In any event, are there any other troubleshooting things for a neophyte like me to try other than going for a new DEC motor encoder board? I realize that replacing that board requires some soldering, but I'm invested now! Thanks in advance.

Where are you located?  No, it is not the handbox problem.  More than likely it is in the mainboard which is where there is another Tantalum cap in the power circuit that pops.  But it can also damage other components when it pops.  These are not for the faint of heart to diagnose and repair. The runaway on the RA could be several problems, not just one.  It could also be the hall effect sensor on the RA motor causing it not to boot.  It cannot find the "home" position and just keeps running one direction.

 

Ignore RichA...  There was only one electrolytic cap in the 10" LX200 Classic scopes. All the rest are film and Tantalum.

[jamtime]

I am in the Dallas, Tx. area.

[E Sully]

You can check out the thread I have on the Classic.  It may help you out.  It shows all the capacitors you should replace. 

I installed the Clearline motor board in my Dec, as well as using the encoder calibration tool to make sure all was in order.  http://clearline-tec...m/products.html

https://www.cloudyni...-classic-lx200/

 

[jamtime]

Thanks for all the responses and helpful suggestions. I eventually took the scope to a company that does industrial electronic repairs, like medical scopes and etc. and in their evaluation they said the microprocessor on the main motherboard was damaged, physically damaged. So I've got a brick. I'll be looking to defork and keep the ota and find a new equatorial mount and sell off the remaining parts.

[Skywatchr]

Thanks for all the responses and helpful suggestions. I eventually took the scope to a company that does industrial electronic repairs, like medical scopes and etc. and in their evaluation they said the microprocessor on the main motherboard was damaged, physically damaged. So I've got a brick. I'll be looking to defork and keep the ota and find a new equatorial mount and sell off the remaining parts.

Bummer.  But you can find mainboards if you look.  I have a couple of spares myself.

[jamtime]

Yeah it's a bummer. I'd probably talk about a replacement motherboard if I knew that was the only issue, but I'm already pretty deep into this reclamation project and with very little electronics expertise or aptitude, I don't know if that's all I'd need to get all the way up and running.

[jamtime]

I have to give a huge shoutout to Skywatchr. While I was debating on how to deal with my dead scope going forward, he approached me about my options on whether I wanted to chase further repair attempts or part it out. He offered to help me either way. The more we chatted the more confidence he had, and I in him, that he might be able to get me up and running again for a nominal charge. He asked me to send him all the electronics and gave very detailed instruction on how to safely disassemble and pack the parts. He replaced bad caps on the control panel board, the R/A and DEC motor boards and one on the handset under the ribbon cable, repaired bad wiring on my handset and most importantly, replaced the main board with a refurbished one he had. When I got everything back and put it all together, everything worked great and my scope has new life. Thanks again dude!

[12BH7]

Wow, that is some story. I'm glad Skywatchr was able to help resurrect this scope.

 

When he does mine, I want him to add speakers and an 8 track. 

[solarity]

Bummer.  But you can find mainboards if you look.  I have a couple of spares myself.

Thanks for helping him out as well as helping me diagnose the issue I was facing a couple months back. This community is greatly aided by people like you as well as the others who have put in the time into collecting/publishing guides!

Edited by solarity, 18 March 2024 - 06:28 PM.

[Skywatchr]

Wow, that is some story. I'm glad Skywatchr was able to help resurrect this scope.

 

When he does mine, I want him to add speakers and an 8 track. 

[happylimpet]

I have to give a huge shoutout to Skywatchr. While I was debating on how to deal with my dead scope going forward, he approached me about my options on whether I wanted to chase further repair attempts or part it out. He offered to help me either way. The more we chatted the more confidence he had, and I in him, that he might be able to get me up and running again for a nominal charge. He asked me to send him all the electronics and gave very detailed instruction on how to safely disassemble and pack the parts. He replaced bad caps on the control panel board, the R/A and DEC motor boards and one on the handset under the ribbon cable, repaired bad wiring on my handset and most importantly, replaced the main board with a refurbished one he had. When I got everything back and put it all together, everything worked great and my scope has new life. Thanks again dude!

What a dude! Nice one skywatchr, and congrats on the working scope! What a heartening tale.

[Skywatchr]

What a dude! Nice one skywatchr, and congrats on the working scope! What a heartening tale.

I just got finished with another one, and it was a head scratcher.  Besides having a "dead spot" in the RA motor, it insisted on running the RA motor at centering speed.  It ended up being the keypad which had several dents and creases in it.  This was an early 12v v2.5 ROM which needs the v3.20 handbox.  I do not have any of those, but bought one in the Classifieds as "unknown version", which has a 3.20 sticker on it's internal ROM chip, but would not boot past the "MEADE".  However the keypad was fine so it wasn't a total loss, and fixed the problem.

Luckily the fella sent me a DEC motor to use parts from, so I converted it into an RA motor assembly because it is impossible to change just a motor because of the pressed-on encoder hub.  But the worm assembly with hall effect sensor can be more easily swapped over.  Unfortunately between the weather, and chemo, I could not get it out under the stars.  So I used the RA setting circle and timed it over 6 hours (in 3 sessions) and the Sidereal speed was spot on each time.  The inherent "growl" of the motor assembly at tracking speed was also "normal" again. The square waves on the O-Scope also finally were "normal".

I used my own 8" to install his "guts" into for the tests.