HL-4070CDW FAQs & Troubleshooting HL-4070CDW Not your product? Sort by: Updated Date Popularity 3 Results 1. 01/27/2014 How do I install the Optional Tray Unit? 2. 05/09/2013 How do I install additional memory? 3. 07/22/2009 What kind of memory can I use? Consumables / Paper / Accessories FAQs & Troubleshooting