monitor arm keeps tilting down

Full Motion Single Monitor Wall Mount with Gas Spring Arm, Fits Monitors Up To 32", Silver

SIIG Dual Stacked Monitor Arm Desk Mount, 17-32", Max Load 19.8lbs Each

Mount-It! Dual Monitor Mount and USB Laptop Tray with Cooling Fan Fits 13 Inch - 27 Inch LCD Screens, Silver

StarTech Monitor Mount for 12" to 30" Screens

Ergotron Desk Mount for Monitor LCD Display Black 45710292

Ergotron Neo-Flex Dual LCD Monitor Lift Stand

Ergotron HX Desk Monitor Arm - 42lb Load Capacity (Polished Aluminum)

Alogic Clarity Fold Stand with 360 Rotation ACFS

Amer HYDRA2 Dual Monitor Mount with Articulating Arms - 15" to 28" Monitors

StarTech Dual Monitor Mount with Full-Motion Arms - Stackable

Mount-It! Full Motion Universal Design Laptop and Tablet Desk Mount Stand Fits 17" Laptops and 11" Tablets | Silver

StarTech ARMDUOSS Up to 24" Adjustable Dual-Monitor Stand

SIIG Dual Monitor Articulating Desk Mount 13" to 27"

Mount-It! Single Articulating, Full Motion, Tilting, Wall Mount For 13 - 32 Inches, Samsung, Sony, Asus, Dell, LG, Sharp, Insignia, ViewSonic - Silver

Mount-It! Dual LCD Monitor Wall Mount for MAX 30 Inch Screen Sizes, Height Adjustable, VESA 75x75mm and 100x100mm, Black

StarTech Desk Mount Monitor Arm Articulating Up to 34" Screen Size ARMPIVOTB2

MSI Mounting Arm for Monitor Matte Black Horizontal/Vertical MAGMT201D

Mount-It! Articulating Computer/TV Monitor Wall Mount for Screens 30 Inches or less, Built-in Quick Release Action for VESA 75x75 & 100x100

Ergotron Mounting Arm for Monitor Dark Gray 45682293

Peerless-AV Paramount Universal Tilt Wall Mount for 37" to 85"+ Displays PT670

Ergotron Mounting Extension Polished Aluminum

Mount-It! Heavy Duty Monitor Desk Mount w/ USB & Multimedia Ports

Mount-It! Single Monitor Desk Mount With Gas Spring Arm | Clamp Base | Modular Design For Future Expansion | Premium Aluminum Cast

Planar AS2 Black Dual Monitor Stand