This post will fix the issue where a Bitmain Antminer L3+/L3++ hash board is absent when your miner starts up or where all 72 chips aren’t displayed on the miner status page.
Table of Contents
Check Your Temps.
Check that the temperatures you are reading are accurate; if they aren’t, there may be a problem with the TMP451 temperature sensor or an LDO.
Reflow Those Solder Joints!
Changes in the environment can affect an intermittent connection. Cold solder joints can flex due to heat and cold, which ultimately results in failures. With regard to the temo sensor, buck converter, and PIC, I’ve discovered that reheating and reflowing the joints has solved previous issues I’ve had with missing components.
Check Voltages at the 10v Buck Converter and 14.2v Boost Circuit.
Sometimes, more frequently than it should, the boost circuit on the hash board malfunctions, causing asics to appear as missing or “xxxxxx.” Additionally, make sure the 10V buck converter’s output matches the voltage you set in the firmware for that chain (i.e. common voltages like 9.5V, 9.8V, or stock voltage of 10.11V.)
Check Voltages at Your Ldos.
Each of the 12 voltage domains in the Antminer L3 is managed by a separate voltage regulator. Though SPX5205 and SGM2202 were previously used by Bitmain, the LN1134 was its most recent device. The voltage at each domain should be checked because in the past these domains have failed when the 14.2V circuit has failed. To do this, measure the voltage between pins 2, the LDO’s middle pin, pin 1, which has a 2.4V input, and pin 5, which has an 1.8V output.) At each LDO, make sure to check this. U75, U76, U77…)
Reload the Firmware.
If the issue is with the PIC, sometimes isolating or even fixing it requires reloading the Antminer L3 firmware, especially if it supports autotune.
Cold Restart the Unit.
The unit can occasionally be restarted after a 30-second shutdown to address intermittent issues like this. Although not a long-term solution, it might temporarily restore your device’s functionality.
Lower the Frequency and Increase the Voltage.
Go to the problem hash board’s advanced settings and try reducing the frequency and raising the voltage to at least 9.8V. The hash boards may operate at the limit of their capability if they are configured to operate at low speed and power. Your issue might be resolved by resetting the PIC to a more typical operating condition. Similarly, operating at too high a frequency or power could potentially shorten the lifespan of components or push functionality to the limit.
