If it's mounted in a standard BA11-K, no. You should be able to pull it out partially (sufficient to tip up if you have rotating slides) and then there should be locking-buttons on the slides to prevent further extension accidentally. Depressing those buttons will allow you to completely remove the chassis and its attached inner slides; the outer slides will remain in the rack. Be careful with full extraction -- the power supply is heavy and the chassis is unbalanced. It's really a two-person operation, or one best accomplished with some sort of supporting mechanism (even wooden cribbing if you are so inclined). If it's anomalously mounted in a BA11-A (like the 11/44) then there is a finger-tab accessible through the front grill on the upper-right that pulls back a spring-loaded side-tab that engages the rack frame to prevent *any* extension whatsoever. Pull that away from the rack-frame and then pull out the chassis. Of course, it's possible that you simply have rusted slides that are binding, in which case you will simply have to use force. Recommend _pushing_ from the rear if "reasonable yanking" from the front isn't working. Although I've encountered a fair share of rusty slides, all have yielded (slowly) to repeated yanking/pushing, even if only a few centimeters at a time. Penetrating oil applied from the sides will help, but after cleaning and polishing the slides suggest that you use graphite or lithium grease to re-lub when reassembling. Others may have alternative lubrication recommendations. -----Original Message----- From: cctech <cctech-bounces at classiccmp.org> On Behalf Of Marc Howard via cctech Sent: Tuesday, March 1, 2022 7:37 PM To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org> Subject: While on the subject of cabinets... I've got a PDP 11/34 I've never opened up. It's mounted in a H9642 cabinet. I can't get the bloody thing to extend on the chassis track slides. Is there a catch or lock screw on this unit? Thanks, Marc Howard