Simcoe Skies Astronomy

LXD-55 Power Supply

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Meade Battery Pack The Meade LXD-55 SN10 - a fast F4 scope with a computerized mount, a goto library of 30,000 objects, the ability to interface to a personal computer, and...

a flimsy battery holder for 8 'D' cells to supply power?
Gimme a break!
To make things even better, Meade, in their wisdom, provided a straight-on plug to connect to the mount, so it could be easily snagged and damaged by the rotating head!

Way to go guys!

4.5Ah 12V Gell Cell
Phase 1
The first thing to get rid of was the battery pack. I didn't even use the supplied pack once. 8 'D' cells to provide 12VDC to slew around 60lbs worth of OTA and counterweights means I'd need to buy Duracell stock. I replaced the Meade "battery wonder" with a 12V, 4.5Ah gel cell rechargeable battery. I simply recharged this battery after each observing session so I'd have it fully charged for the next. Piece of cake! Oh, and if you do this, be SURE to add a 6A (or so) fuse AT the battery, in case it shorts, and use a polarized connector plug so that you can't hook it up backwards!

90 degree power plug

low profile locking bolt After a near-disaster while slewing, when the OTA saddle plate locking knob almost destroyed the power plug at the mount, I decided that 2 additional changes were in order:

change the power plug (at the mount) to a 90 degree connector

change the OTA saddle plate locking knob to a short bolt to minimize clearance requirements

desktop PC power supply

UPS, power supply, cord
Phase 2
After lots of observing sessions with multiple batteries (I used a separate one for my dew heater), I grew tired of lugging lead-acid batteries indoors and out and the charging cycles, and decided that a permanent AC powered solution was in order. Now where could I find a power supply capable of spitting out a nice reliable 12VDC at 6 Amps or so?

An old PC power supply!
NOTE: this should be an old "AT" type power supply (with 2 motherboard plugs), not the currently available "ATX" ones (with a single motherboard plug). Apparently the new ATX power supplies don't regulate well without a significant 5V load.

This has several great selling points:

it's FREE (when ripped out of a junked obsolete computer)

it's designed for sensitive electronics and microprocessors

it's self-contained in an enclosure and has a switch (also removed from the PC and duct-taped for extra insulation from 120VAC)

it's not going to landfill anymore
After checking in my computer graveyard collection, I found a power supply with 12V@8A and 5V@20A. This would suffice nicely - not only for 12V power for the mount and dew control, but also for any 5V logic stuff that I might want to add! After removing it from the computer, I opened the case, and cut all the wires back, except for a single 4-wire "hard drive power" type cable. The number of wires was reduced to 3 (there was an extra ground), two 7A fuses were added immediately leaving the enclosure (one on each 5V and 12V supply), and the connector was re-attached. Not only is this now my scope power supply, but it makes an excellent electronics workbench supply when needed.
I bought a 50' length of "garden appliance" grounded power cord, cut the ends off, and wired the 3 wires (+12, +5, Gnd) to the same type of connectors that were cut off the PC's power supply, so that I could leave the "power box" in the house. Add to this a 350VA UPS/battery backup, and you've got hearty power that you can really trust!
Note: the PC power supply is NOT weather resistant and can pose a serious shock hazard if used outdoors!.

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Meade Battery Pack			The Meade LXD-55 SN10 - a fast F4 scope with a computerized mount, a goto library of 30,000 objects, the ability to interface to a personal computer, and... a flimsy battery holder for 8 'D' cells to supply power? Gimme a break! To make things even better, Meade, in their wisdom, provided a straight-on plug to connect to the mount, so it could be easily snagged and damaged by the rotating head! Way to go guys!

4.5Ah 12V Gell Cell			Phase 1 The first thing to get rid of was the battery pack. I didn't even use the supplied pack once. 8 'D' cells to provide 12VDC to slew around 60lbs worth of OTA and counterweights means I'd need to buy Duracell stock. I replaced the Meade "battery wonder" with a 12V, 4.5Ah gel cell rechargeable battery. I simply recharged this battery after each observing session so I'd have it fully charged for the next. Piece of cake! Oh, and if you do this, be SURE to add a 6A (or so) fuse AT the battery, in case it shorts, and use a polarized connector plug so that you can't hook it up backwards!

90 degree power plug low profile locking bolt			After a near-disaster while slewing, when the OTA saddle plate locking knob almost destroyed the power plug at the mount, I decided that 2 additional changes were in order: change the power plug (at the mount) to a 90 degree connector change the OTA saddle plate locking knob to a short bolt to minimize clearance requirements

desktop PC power supply UPS, power supply, cord			Phase 2 After lots of observing sessions with multiple batteries (I used a separate one for my dew heater), I grew tired of lugging lead-acid batteries indoors and out and the charging cycles, and decided that a permanent AC powered solution was in order. Now where could I find a power supply capable of spitting out a nice reliable 12VDC at 6 Amps or so? An old PC power supply! NOTE: this should be an old "AT" type power supply (with 2 motherboard plugs), not the currently available "ATX" ones (with a single motherboard plug). Apparently the new ATX power supplies don't regulate well without a significant 5V load. This has several great selling points: it's FREE (when ripped out of a junked obsolete computer) it's designed for sensitive electronics and microprocessors it's self-contained in an enclosure and has a switch (also removed from the PC and duct-taped for extra insulation from 120VAC) it's not going to landfill anymore After checking in my computer graveyard collection, I found a power supply with 12V@8A and 5V@20A. This would suffice nicely - not only for 12V power for the mount and dew control, but also for any 5V logic stuff that I might want to add! After removing it from the computer, I opened the case, and cut all the wires back, except for a single 4-wire "hard drive power" type cable. The number of wires was reduced to 3 (there was an extra ground), two 7A fuses were added immediately leaving the enclosure (one on each 5V and 12V supply), and the connector was re-attached. Not only is this now my scope power supply, but it makes an excellent electronics workbench supply when needed. I bought a 50' length of "garden appliance" grounded power cord, cut the ends off, and wired the 3 wires (+12, +5, Gnd) to the same type of connectors that were cut off the PC's power supply, so that I could leave the "power box" in the house. Add to this a 350VA UPS/battery backup, and you've got hearty power that you can really trust! Note: the PC power supply is NOT weather resistant and can pose a serious shock hazard if used outdoors!.