TC not giving timely IP addresses to non-Apple devices

I use a 2nd generation time capsule set up as the primary router with a cable modem connection to the internet and an Extreme as a bridge attached by an ethernet cable. My DHCP range set by the TC is in the 10.0.x.x range. I had problems previously with the extreme getting IP addresses out of range (192.168.x.x) which I couldn't figure out but worked around by assigning a static IP address in range. Everything worked great for over a year.

I have a large-ish network with upto 28 devices, many of them Sonos equipment which handles its own subnetwork with IP's handed out by the TC. Recently the TC has not been timely in handing out IP addresses to non-Apple devices such as my sons' and guests' PC laptops, Kindle Fire and some sonos controllers. The Kindle and controllers power down to save battery, so I thought it might be a leasing issue but increasing the lease to one day still had delayed or no IP assignment on wake up within the lease time.

Even when I reserve the IP addresses for these devices, they don't always connect. The Kindle and the PCs will say they connect to the network (sometimes with a number after the network name, ssid2 for example when the network is ssid) but they can't get to the internet because the IP is in the 192.168.x.x range. I have tried a hard reset. I am thinking of changing the range into the 192.168 range on the TC but that will mean rebooting all these devices. My and guest apple devices don't have any problems getting on the network or getting to the internet.

Anyone have any ideas or had similiar problems? Thanks in advance for any help.

JMD