Replacement for Meade #1812

I'm a high school astronomy teacher, new to my school, and I've inherited an old LX200 (perhaps "classic" but I'm not sure how to tell) that hasn't been used in many years. I'd like to use it for student stargazing trips, but it seems the #1812 power supply isn't working. I measure 12v going in but I get nothing coming out. As best I can tell, Meade doesn't sell these anymore. I've struck out at Astromart Classified and the only option I found on Ebay seems overpriced. My question is how precisely 18v does the LX200 require? This item interests me:
https://www.amazon.com/uxcell-Converter-Regulator-Waterproof-Transformer/dp/B01H97ETP8/ref=sr_1_3?crid=HZXU253T3C7T&keywords=12v+to+18v+step+up+converter&qid=1647553010&sprefix=12v+to+18v+step+up+converter%2Caps%2C76&sr=8-3
It seems like a great price on a robust piece of electronics, but I'm a little worried that 19v instead of 18v will be a problem.
Thanks,
-Mark

Do not use an 18v or larger power supply. Meade LX200 Classics have underrated capacitors that will finally blow eventually. You want a regulated 12v power supply. The scope will run just fine on 12v, just won't slew as fast.
Here is the replacement power supply I am using. https://www.amazon.com/dp/B07X7HLF6W?psc=1&ref=ppx_yo2_dt_b_product_details

Go here for 1st info to look at. Copy and paste into browser.
https://www.cloudynights.com/topic/441307-replacing-caps-on-an-lx200-classic/?hl=+lx200%20+classic%20+electrical
You can search for more on replacing the caps. Cloudynights.com is really a must if you want info. If you aren't comfortable replacing the caps or know someone you trust to do so, then the George Dudash upgrade is best. See all below links.

Now look at this YouTube video 
https://www.youtube.com/watch?v=Nv2tshAsO8k

Now go to 
https://groups.io/g/LX200Astar/topic/the_autostar_audiostar/71655379?p=,,,20,0,0,0::recentpostdate/sticky,,,20,2,0,71655379,previd=1647533534736302922,nextid=1583084339679734492&revid=1647533534736302922&nextid=1583084339679734492

Go here for more info
https://groups.io/g/LX200Astar/topics

Link to what to do
https://groups.io/g/LX200Astar/attachment/4/0/LX200MotorAssemblyRemoval.pdf

Finally, you can contact George Dudash : [email protected]

Thank you for all this detail! I'll dig in to it.

Here's another link https://www.cloudynights.com/topic/814396-replacement-power-supply-for-lx200-classic/?hl=%2Blx200+%2Bclassic#entry11765053
Cloudy Nights is a great resource.
Don't fire up the scope until you have looked all this over. Those scopes have a nasty habit of burning out the electronics after sitting awhile. It's not a matter of if, but when. Things I would do at a minimum before turning on/powering up are

1. Clean out and replace the grease in the RA and DEC gears.
2. If while cleaning out grease you find plastic gears, go to https://petersonengineering.com/bucks-gears-selection/ and purchase the correct Bucks Gears set for your scope. Those plastic gears are really old and brittle now, you really need to replace before they break and burn up a motor..
3. While on Peterson Engineering site, look over the other upgrades https://petersonengineering.com/meade-upgrades/ They are worth it.
4. Replace the capacitors, but better would be the George Dudash upgrade for electronics.
5. Seek school board approval for upgrades, the cost of these is much less than replacing a scope and the old LX200 Classics are still workhorses, otherwise they wouldn't still be around.
6. Lastly, there is a GPS rollover issue where the GPS info is not good after around 2017. Get and use starpatch (not the Meade updater) to update the software asp. in the handset. Identify your handset and get a correct com port cable for downloading use. They make a cable https://www.amazon.com/dp/B08KRVQLCK?ref=ppx_yo2_dt_b_product_details&th=1

with a CP2102 Chip PC RS232 Serial RJ12 6P6C Upgrade Console Cable that connects a newer PC USB as a serial port. You go to the site the manufacturer gives to download the driver, and when installing the cable to the computer, load the driver from where you saved it to on your computer. Cloudy nights have forums to help for all of this.