So I have a TP-LINK TL-MR3020 v1.9 (SoC AR9331-AL3A). It had a Zentel A3S56D40GTP-50 RAM chip (32 MB). I decided to upgrade it to 64 MB RAM and decided to buy a Hynix HY5DU121622DTP-D43 chip after seeing the wiki for the 64MB mod for the TL-WR703N. I'm not an hardware expert but the specs between the 2 RAM chips seemed equal (protocol used, voltage etc) so I decided to go for it and replaced it today.
Needless to say the router seems bricked. The power led stays ON forever (it never blinks) and the reset LED blinks only once at the very start.
Is the Hynix HY5DU121622DTP-D43 incompatible for the TP-LINK TL-MR3020 v1.9 model? The soldering was done by a professional and was checked under a digital microscope.
Did any of you upgraded the RAM of yours too? If so which chip did you use? Thanks in advance.
Thanks for your help, now I made my tl-mr22u works with OpenWrt!
I also found out what leads to my failure, it is 64MB RAM! I have tried ESMT M13S5121616A and Micron MT46V32M16P. They are 8Megx16bitx4Banks DDR, and works well on tl-mr10u(AR9331), but mr22u won’t start up with them, it only runs when I solder the 32MB 4Megx16bitx4Banks DDR(ESMT M13S2561616A). There is no difference in pin arrangements between 4meg RAM and 8meg one. Maybe you’ll be interested in this phenomenon.
eventually i gave up on my mod attempt
if you got any success with different kind of ram chip please keep us updated
If uboot can't start, most of issue is soldering not good.
I used this ram chip on some router and it work well.
Let check Vdd & Vddq pin ~2.6v, this chip required 2.6v (+0.1/-0.2v) for running 400mhz speed.
Thank you all for your replies. Since the guy who soldered the chip won't be able to do it again (he'll change job soon) I asked him today to solder back the old chip. And he did... And 2 pads popped out during the process...
But unfortunately the router exhibits the same behavior as before, with the power led staying on forever.
Maybe I'll try to do more tests or maybe I'll just give up. I'm starting to think it either got damaged during the upgrading process or I had a defective IC which damaged the router. I don't really know at this point.
If I find something I'll keep you updated. Thank you again.
I have replaced ram for a good amount of routers with that hynix chip. I'm waiting for my 3rd. batch of that chip hy5du121622DTP-D43. It is compatible with tplink 840v2/v3 841v9/10/11, mr3420 for sure, as I did changed their ram with that chip.
I'm gonna do it again(chip not in hand now) with some more 840 v3 routers with same chip and replace exact same zentel as56040gtp-50 or 50L(some winbond), shall see how it goes.
For replacing ram chip with tsop-66,
Always desolder with hot air rework or a hot air gun with proper nozzle.
Need quality Flux, flood it.
U used tape that I always use, otherwise tiny registors/caps will come off very easily.
I hv always took out the pins(UART Riser) before I do any ram or flash chip change. While I was starting I had problems, short out UART pins, as a result no boot!!, as hot air guns produce a lots of heat!!, melt and bridge solder inside the pads(for flash chip of 840 routers).
Always used a fine tipped iron for solder back original or new chip.
Always used pepe2k u-boot for qca/atheros before changing ram!! cfe is more forgiving.
Replace ART after upgrade flash or no wifi or kernel panic.
visual check is insufficient. see my photo: the chip looks like is soldered fine, but there is no connection. multimeter confirms it. after flux+iron rework, connections appeared and the upgrade worked