Repairing A Couple Of Very Costly Registered DDR5 RAM Sticks

It’s undoubtedly an indication of the instances when restore outlets get handed sticks of registered ECC DDR5 RAM by companies to attempt to repair, fairly than simply tossing the faulty ones and slotting in a recent bunch. This is how [northwestrepair] ended up with two of these ECC RDIMMs, with a present market valuation of a fairly good finances automobile.

The 128 GB stick was first on the bench, with the fault being that it will fail DDR5 coaching on boot. This means that a number of of the DRAM BGA packages had developed a cracked solder joint, which is one thing that you may conceivably repair with extra diagnosing and testing for a single IC reballing.

In this case doing a reflow cycle was sufficient to convey the RAM again to life, with the DDR5 coaching now passing with out points in a take a look at system.

For the 256 GB stick issues wouldn’t be really easy, because it appeared fully lifeless. This advised a lifeless PMIC, as that is the element on DDR5 RAM liable for guaranteeing that the DRAM ICs even energy on. The SPD ROM was an alternative choice, in order that bought swapped first, which does require reprogramming the RDIMM. For this the sooner SPD dump picture was reflashed, however swapping this chip made no distinction.

After some further reflowing of some suspect ICs, nonetheless nothing occurred. Following this lots of reballing and different troubleshooting steps adopted, just for the issue to be one shorted MLCC and a damaged PMIC, doubtlessly attributable to whoever dropped mentioned RDIMM onto the server room ground.

Cracked MLCCs do look like a quite common reason behind failures, as they’re typically used as filter capacitors, similar as for this RDIMM. Checking for shorts throughout various such MLCCs could be a good solution to shorten a diagnostic cycle. Since this RDIMM was dropped, reballing each IC most likely was nonetheless a great transfer as this will likely have cracked some solder balls.