Hello,

I have an existing WiFi setup as shown in the attachment (PNG file)

It works fine.  Before I state my question, I thought I'd reiterare the following:

(1)  the main router has WiFi disabled -- because it keeps dropping and I couldn't fix it with all the help I've got.

(2)  so I bought a new TPLINK A7 and made it Router-3 and -- configured it to AP Mode (a TPLINK built-in feature).

(3)  Router-1 and Router-2 have their own DHCP server enabled.

Statement of the problem:

I have an old DLINK Dir-615 which functions perfectly well.  In fact it was used temporarily (also as AP) in place of Router-3 until I got the new A7.

I wish to configure the the DLINK as another AP and connect it physically (using wired, i.e., Ethernet cable) to Router-3.

Q1 - can this be done?  If so how?  I tried the following and they all failed:

T1 - connect from LAN  port of DLINK   to   LAN port of Router-3  >> this led to "no internet access" on both boxes (the Internet LED on Router-3 turned orange)

T2 - connect from WAN port of DLINK   to   LAN port of Router-3  >> same results/errors.

I note that I had reconfigured the DLINK as follows:   Turn OFF DHCP.   

The DLINK does not have a "AP Mode operation" like the TPLINK A7 (Router-3).

Related DLINK wireless settings:

    Mixed 802.11 bgn

    Auto channel scan = YES

    Channel width = 20 Mhz

    Security mode = WPA Personal

    WPA mode = Auto WPA or WPA2

    Visible SSID

    Assign a SSID different from the one used in Router-3 (I understand I could have used the same SSID but that, I am told requires more changes)

Any tips, suggestions and/or guidance will be highly appreciated.  Thanking you in advance.

Sincerely,