I got this router but it wont power on. Will try to repair. It seems to have a good support on openwrt but it is from 2014. 1400mhz dual core. Wifi seems good. Only 5ghz problematic on the wiki, but it may have been fixed since then. Anyone still using it? It has AC2350, very nice.
Everything is worth the try. As long as it doesn't take too much time and money.
As a hobby you can also invest more time and money (e.g. for tools which come handy in other repairs :- ) You also learn something and get some practise
r7500v2 should still be a very reasonable router for OpenWrt, a tad short on RAM, but still a nice device.
r7500 (v1) comes with quantenna topaz 5 GHz wlan, which is unsupported (and very unlikely to ever will be supported). So if you want to continue using it, OpenWrt will not be your primary focus (unless you only need a wired+2.4 GHz wlan router), leaving you only with the stock OEM firmware.
Repairing routers is always an economic question (disregarding your personal time, but very much considering the financial expenses for debugging tools, soldering equipment and replacement parts, which quickly surpass the cost of a buying a working (second hand-) device), so you have distinguish different cases of problems here. These devices have very mature push-button tftp recovery mechanisms, so (almost) any software issue (soft-bricked) should be easily recoverable without any expenses within ~15 minutes (just involving running a tftp client on a computer, two ethernet patch cables and an unmanaged switch between them); for this, the device doesn't have to be opened.
If this doesn't succeed after a dozen attempts, chances are worse and you would have to escalate your recovery attempts --> opening the device, attaching a matching 3.3V usb2serial adapter (costs, around 5 EUR for the adapter with local/ fast shipping or ~1.5 EUR by the slow boat from China). As long as you feel confident about this, doing so is still sensible and might help uncovering what's the problem - however, considering that the push-button tftp recovery should have succeeded already, chances to fix it this way aren't that great (but they could be on other devices, without a reliable push-button recovery).
Beyond this, you really need quite a few tools and devices to continue debugging - unless you already own those (soldering equipment in particular) or want to make this your new hobby, it's rarely a sensible approach - and NAND based devices (such as the one in question) don't allow easy external reflashing anyways.
Finding and fixing hardware defects, beyond the easy approach of just trying a different power supply or replacing visibly damaged capacitors requires a much deeper understanding of- and experience with the topic, either you can already do that - or you won't learn it now (multimeter required, scope recommended, logic analyzer helpful - and pretty advanced soldering equipment required; 'common' spare electronic parts (resistors, diodes, capacitors, inductors, voltage regulators) should be at hand). This exceeds the costs of multiple brandnew high-end routers quickly. If you have that, and the knowledge to use it, great - then it'll only cost you your time and a few pennies for the replacement parts you actually need - if not, it's not going to be economically viable.
Seeking the services of a professional company is rarely viable, the up-front costs will already exceed the costs of a new device.
I think I saw that cost of repairing stuff is extremely high in countries like Germany, or USA. Not so much here. It will probably cost around 15$ to repair this.
Even that is (with a bit of luck) already in the price range of a used ASRock g10, which is pretty much the same with actually supported (QCA9980) 5 GHz wlan - or brandnew dap-x1860/ covr-x1860/ wsm20 802.11ax APs.
Asrock is not sold here. Only wifi6 tplink routers with no USB such as AX23, AX53. Good openwrt support, cheap but no USB sucks.