Antminer S19 Series — Common Issues Across All Variants

Overview

The Antminer S19 series encompasses multiple models spanning three years of production. While each variant has model-specific characteristics, many failure modes are shared across the entire family. Understanding these common issues helps technicians diagnose problems faster regardless of the specific model.

This guide covers the most frequently encountered problems across all S19 variants and their solutions.

S19 Family Model Comparison

Common Issue 1: Hashboard Connector Failures

Affects: All S19 variants

The 18-pin hashboard connector is the most common single point of failure across the entire S19 family. High current (up to 90A per hashboard) flowing through small connector pins causes overheating over time.

Symptoms:

• Intermittent hashboard detection ("chain find 0 ASIC" that comes and goes)
• Hashboard works in one slot but not another
• Burnt smell near the connector area
• Visible discoloration on connector pins

Diagnosis:

1. Inspect both ends of the connector (control board side and hashboard side)
2. Look for darkened, oxidized, or melted pins
3. Check for loose fit — the connector should click firmly
4. Measure voltage at the hashboard side vs the PSU side — a drop >0.3V indicates high resistance in the connector

Fix:

1. Clean oxidized pins with a contact cleaner (DeoxIT D5)
2. Replace badly damaged connectors (requires soldering)
3. Apply dielectric grease to clean pins as prevention
4. Ensure connectors are fully seated

Common Issue 2: PIC Communication Errors

Affects: S19, S19 Pro, S19j Pro (PIC variant), S19 Hydro

The PIC16F1704 microcontroller manages hashboard identification and I2C sensor communication. PIC failures are one of the most common S19-family issues.

Symptoms:

• "PIC communication error" in kernel log
• "EEPROM read error" at boot
• Hashboard detected but temperature readings show -1 or 999
• Hashboard intermittently disappears

Diagnosis:

1. Check I2C bus voltages: SDA and SCL should read 3.3V when idle
2. If either line is at 0V, the bus is shorted — could be PIC, sensor, or pull-up resistor
3. Check PIC VDD pin: should be 3.3V
4. Disconnect all I2C devices (desolder one leg of pull-up resistors) and recheck bus

Fix:

1. Reprogram the PIC: Connect PICkit 3/4 to ICSP pads, flash correct hex file
2. Replace the PIC: If reprogram fails, desolder and replace with new PIC16F1704
3. I2C bus repair: Replace shorted pull-up resistors or sensors that are pulling the bus low

Common Issue 3: Temperature Sensor Failures

Affects: All S19 variants

LM75A (or compatible) temperature sensors report chip temperatures to the control board. Failed sensors cause incorrect temperature readings, leading to unnecessary thermal throttling or shutdowns.

Symptoms:

• Temperature reads -1, 0, or 999 in web dashboard
• "Temp too high" error when the board is physically cool
• Fans running at 100% despite normal temperatures
• Thermal shutdown at low ambient temperatures

Diagnosis:

1. SSH in and check raw temperature data: cat /tmp/temp.txt
2. For PIC variants: the sensor data passes through the PIC I2C bridge — check PIC first
3. For noPIC variants: check the I2C bus directly at the sensor
4. Measure I2C pull-up resistors (4.7kΩ to 3.3V typical)

Fix:

1. Replace the failed LM75A sensor (SOT-23-5 package, straightforward soldering)
2. If the I2C bus is shorted, isolate and replace the offending component
3. As a temporary workaround, some custom firmware allows disabling individual sensor inputs

Common Issue 4: EEPROM Corruption

Affects: All S19 variants

The AT24C02D EEPROM stores hashboard serial number, calibration data, chip frequency map, and hardware revision information. Corruption causes identification failures.

Symptoms:

• "EEPROM read error" or "EEPROM checksum error"
• Board detected as wrong model
• Hashrate significantly below expected (wrong frequency map loaded)
• Board not detected at all

Diagnosis:

1. Check I2C bus integrity (EEPROM at address 0x50)
2. Attempt to read EEPROM using an I2C tool or programmer
3. If data reads as all 0xFF or all 0x00, the EEPROM is erased or failed

Fix:

1. Reprogram the EEPROM with correct data for the board model and revision
2. If the EEPROM chip has physically failed, replace it (8-pin SOIC package)
3. EEPROM data can sometimes be recovered from a working board of the same model and copied

Common Issue 5: Voltage Regulator Failures

Affects: All S19 variants (especially S19 and S19 Pro with 38 regulators each)

Each voltage domain has a dedicated buck converter. With 38 regulators on S19/S19 Pro boards, the probability of at least one failing over the miner's lifetime is high.

Symptoms:

• One or more domains reading 0V
• Domain reading abnormally high voltage
• Visible damage (burnt or cracked) on regulator components
• Output inductor open circuit

Diagnosis:

1. Measure each domain's output voltage
2. For 0V domains: check if the issue is a shorted chip pulling voltage down or a dead regulator
3. Isolate by checking domain resistance — low resistance + 0V = shorted chip; normal resistance + 0V = dead regulator

Fix:

1. If shorted chip: replace the chip (see model-specific repair guide)
2. If dead regulator: replace the controller IC, check MOSFETs, check inductor continuity
3. Check input/output capacitors for shorts

Common Issue 6: Thermal Paste Degradation

Affects: All S19 variants (especially units in 24/7 operation for >12 months)

Thermal paste between ASIC chips and heatsinks degrades over time, reducing thermal conductivity and causing elevated temperatures.

Symptoms:

• Gradually increasing chip temperatures over weeks/months
• Thermal throttling (hashrate drops during hot periods)
• Temperature difference >15°C between ambient and chip temp compared to when new
• Intermittent "temp too high" warnings

Fix:

1. Remove heatsinks, clean old paste with IPA
2. Apply fresh thermal paste (Arctic MX-5 or equivalent)
3. Reinstall heatsinks with proper tension
4. See the S21 Thermal Maintenance Guide — procedure is similar for S19 models

Common Issue 7: Fan Controller Issues

Affects: All S19 variants

Symptoms:

• "Fan speed error" in web dashboard
• Fans not adjusting speed (stuck at 100% or not spinning)
• Thermal shutdown due to cooling failure

Diagnosis:

1. Check fan connector pins on control board
2. Test fan independently with 12V power
3. Check tachometer signal (4th wire) with multimeter or oscilloscope
4. Verify fan PWM output from control board

Fix:

1. Replace failed fan with correct model
2. Clean fan connector pins
3. For control board fan controller IC failure — may require control board replacement

Common Issue 8: Firmware Compatibility

Affects: All S19 variants

Using incorrect firmware for the specific S19 variant can cause serious issues:

Symptoms:

• Board not detected after firmware update
• Wrong hashrate target
• Frequency and voltage mismatches
• Boot failure or boot loop

Prevention:

1. Always verify the firmware version matches your exact model (S19 ≠ S19 Pro ≠ S19j Pro)
2. Keep a backup of working firmware on an SD card
3. When using custom firmware, verify S19 variant compatibility before installing

Model-Specific Quirks

Diagnostic Flowchart

Board not detected?
├─ Check connector (reseat, inspect pins) → Still not detected?
├─ Check 12V input voltage → 0V? → PSU or cable issue
├─ Check PIC communication (PIC models) → PIC error? → Reprogram PIC
├─ Check EEPROM (I2C read test) → EEPROM error? → Reprogram EEPROM
└─ Check first chip in signal chain → Dead chip? → Replace chip #0

Board detected but low/no hashrate?
├─ Check domain voltages → Failed domain? → See domain repair
├─ Check chip count → Missing chips? → Signal chain break → Binary search
├─ Check temperatures → Too high? → Thermal maintenance
└─ Check firmware → Wrong version? → Flash correct firmware

Troubleshooting FAQ

Can I swap hashboards between different S19 models?

No. Each S19 variant uses different chips, domain configurations, and firmware expectations. Hashboards are only interchangeable within the same model (e.g., S19 Pro boards can be swapped between S19 Pro units).

Which S19 variant is easiest to repair?

The S19 and S19 Pro are easiest because the BM1398 uses a QFN package (simpler than BGA) and the domain architecture (2 chips per domain) makes fault isolation straightforward. The S19 XP is hardest due to BGA rework requirements.

How do I find replacement chips for S19 models?

BM1398 (for S19/S19 Pro) and BM1362 (for S19j Pro/S19k Pro) chips can be sourced from mining hardware parts suppliers. Alternatively, harvest working chips from scrap boards of the same model.

Should I still repair an S19 given its age?

The S19 Pro at 110 TH/s is still profitable at reasonable electricity costs. Repair is cost-effective if limited to 1–5 chip replacements. For extensive damage (>5 chips or multiple regulator failures), compare repair cost against replacement board pricing.

What is the PIC address scanning issue?

The PIC16F1704 on S19/S19 Pro boards can shift its I2C address between 0x20 and 0x27 across power cycles. Your diagnostic software should scan this entire range rather than hardcoding a single address.

Related Guides

• S19 Pro Hashboard Repair
• S19j Pro Hashboard Repair
• S19 XP Hashboard Repair
• S21 Hashboard Repair
• Multimeter Testing Guide
• ESD Safety Guide