Denon employed a rigid chassis design to minimize mechanical vibration—a critical factor for a device that reads magnetic tape. Vibration can cause "wow and flutter" (pitch instability), and by reinforcing the base and using heavy shielding, Denon ensured the transport mechanism remained stable even at high volumes.
For further details or troubleshooting, you can check the Denon Product Archive for legacy manuals. If you're looking to buy these, Denon-SC-E727R - www.hifi-guide.com denon sc-e727r