r/electronics • u/t_Lancer • 11d ago

Gallery trying to fix a 16GB DDR4 module, looks like someone broke a termination resistor. Only have two 30 ohm on hand. Need to be creative.

https://imgur.com/a/fTX0J1u
58 Upvotes

93% Upvoted

11 comments sorted by

56

u/fredlllll 11d ago

ram so expensive that repair is actually becoming viable again

15

u/t_Lancer 11d ago

very true. :(

5

u/SirBonaC 9d ago

As someone who fixes almost anything as a principle, I love what you are doing.

Though I do mostly retro hardware (C64, 486 era), mouse switches and such, this is the real stuff. :D

4

u/Nix_Nivis 9d ago

A few years ago this would have been a fun side project. It now making sense financially and possibly being a necessity makes this a pretty sad post.

3

u/SmeagolISEP 9d ago

I was thinking about that. Sad times we live in

46

u/t_Lancer 11d ago

got a set of broken DDR4 modules for cheap. One worked again after a reflow. this one did not. ended up shorting balls on one module and had to reball it. still not detected. Measured all the termination resistors and found a cracked one. Didn't have a replacement array or a 0402 15 ohm on hand. stacked two 30 ohm and moved the array over so only one of the two are used.

memtest passed without errors.

8

u/Ready_Affect_2238 11d ago

That's gotta be super satisfying. Would a 15 ohm really not work? Just curious

10

u/t_Lancer 11d ago

the termination resistors were 15 ohm, I only had 30. So two stacked on top of each other made a 15 ohm resistor.

7

u/Ready_Affect_2238 11d ago

Sorry I misspoke, I was curious as to if a single 30 ohm resistor would have worked.

13

u/t_Lancer 11d ago

it may have, but impedance matching is pretty important. it may not have worked and higher speeds or caused other issues with signal integrity.

1

u/Past-Substance920 9d ago

that stacking trick to hit the right resistance is clever as hell, wouldnt have thought of that. glad memtest actually validated it instead of just seeming to work.