Category Archives: Bitcoin News

Bitmain S4 : Have a Fire Extinguisher Near By !

Original Story happen here :
Hashtalk S4 Burnout Power Supply

Bitmain S4


* Chip Operating Voltage: 0.72V

* Chip Quantity per unit: 160

* Hash Rate: 2,000GH/s guaranteed

* Power Efficiency: 0.69Watt/GH/s at the wall

* Over clocking: About 10%, but not guaranteed

* 3U Rack 432mm*442mm*133mm

* PSU inside: 1400W, 80PLUS gold, C14 input socket. Power line not included. You may look for one line with no less than 16A in your local market

* Temperature: 40-50 degree Celsius tested in the mining farm

* Fan Speed: 3900RPM

* Stable but a little bit noisy

* Ethernet connection, Stand alone

* Certificate Compliance: FCC/CE

My Quick Power Calculation

First the supply specs

* PSU inside: 1400W, 80PLUS gold, C14 input socket. Power line not included. You may look for one line with no less than 16A in your local market

How much power is needed?

* Power Efficiency: 0.69Watt/GH/s at the wall

0.69W/GH/S * 2000 = 1380W of Juice at 0.72V.
1380W/1400W * 100 = 98.5% Load

Overclocking without popping out the breaker or P/S don’t surprise me.

0.80V is 10% more juice in OC
1380W * 10% = 1518W

Overload …

This one must be understand carefully :

Power line not included

Have you a big enough AC plug cable ?

You may look for one line with no less than 16A

Cheap AC plug max amps around 10A


Watts = Voltage * Amps
Amps = Watts / Voltage

You need :
On 120V circuit, 1518W/120V = 12.65A.

If your overload AC cables, overheating will happen also voltage drop.

Breaker in Canada are rated 15A on 120V circuits.

Startup current is huge on those machines too.
Lot’s of capacitor and inductance to filter power line noises.
Mean, need juice at startup or current- inrush can be 10-20% more for few milsec

Think about it

Going 220V could be safer, reduce by half amp in wiring
Quality power supplies have universal input.
Rated 120V-220V, 50-60Hz.
Min 2000W Power supply recommended !

Now time to unplug the dryer I guess ; )

Here some pics of his power supply

S4 Under Power Supply

Blow-out S4 power supply

S4 Plan B Power Supply

S4 Burnout Black PCB

S4 Faulty power Supply

This guy manage to safe the day and put a plan B in action, changed power supply and miner up again.
Lucky this time, at least the supply died like a heroes, protect circuits of damage when blowing up.

Update : Bitmaintech answer and fix the problem quickly.

Dear customers,

We are sorry to inform you that we do find a critical defect of power supply in the first batch and the first part of batch 2 Antminer S4 shipment, and have issued an official announcement on bitcointalk community regarding power supply replacement for these miners. Please find details in the following link,

We assume you might have not came across the failure issues like other customers do as we have not yet received any info from you on the power supply problems. But we do suggest you nip it in the bud and keep an eye on your miners which seems to be running well.

we decide to send you new replacement PSUs, which have been optized and improved from the previous ones and will avoid similar issues as stated in the above-mentioned link.

Now please provide us with the Order Confirmation page from of your B1 or first part of B2 S4 miners and confirm with us your full address, to which we will ship out new replacement PSUs.

Please accept our sincere apology for the inconvenience.

Tim Shao


BESt Regards

Reply Post on

Dear loyal customers,
Today we have found out that the batch of power supplies shipped out in batch 1 and the first part of batch 2 Antminer S4s contain a critical defect. The customized power supply produced by AplusPower Co. Ltd is suffering from an unacceptably high failure rate and will be replaced with immediate effect.
We take full responsibility for the problems caused and had not anticipated the unique loading conditions of a miner when selecting and testing the suitability of these power supplies. You can read more about the defect in the post below.
We are now taking steps to ensure that customers are impacted as little as possible. The rest of batch 2 S4s will come with the improved power supply as standard.

The following actions are being taken for miners already delivered:
1) If your PSU has already failed:
• Submit a RMA request with some pictures and proof [ie with your username in the photo] of your PSU’s failure to
• We will then ship a new PSU out as soon as possible.
• We will also issue compensation to the value of 10 days of mining profit calculated starting from shipping date
2) If your PSU has not failed and the miner is running normally:
• We will ship a new PSU to you.
• Please do not contact support yet, you will receive an email asking to confirm your shipping.

Analysis of power supply failures within the first batch of Antminer S4s

We are sorry for the inconvenience you may have experienced regarding power supply failures, or even sporadic events of smoke from our first batch of Antminer S4s. We immediately set out to investigate the reports of failed power supplies from customers, and have made immediate changes to improve the quality of future deliveries. What happened with these power supplies is not acceptable.

The power supplies failed by two different mechanisms:

1) Failed TR1 or TR2 MOSFETs on the power factor correction (PFC) circuitry.

After investigations, it was found that the unusual service conditions a miner puts on its power supply was the cause of the failure. The repeated abrupt, dynamic loading generated significant current through the PFC circuits, eventually leading to the failure of the TR1 or TR2 MOSFETs.

The replacement power supplies have significantly upgraded PFC circuits in order to improve performance and prevent a recurrence of the problem.

2) Failed MOSFET on the output Synchronous rectifier circuit

A MOSFET on the output Synchronous rectification circuit was also found to be failing, due to the repeated and sudden load changes during the miners’ operation.

During normal operation, the output MOSFET is expected to carry a current of approximately 30A and operate at a surface temperature of around 80C. The failing MOSFET was found to be heating up significantly further than this, causing the carbonized black PCBs and smoking thermal pad.

It is worth noting that although a failed output MOSFET at high temperatures may result in some smoke from the PCB and thermal pad, it will not start a fire. All internal components of the PSU meet the requirements of the UL94-V0 flame retardancy standard, which certifies that any ignition will self-extinguish within a maximum of 10 seconds.

In response to this problem, the sample filter in the Synchronous rectifier circuits have been altered to erase the excessive current, and so the MOSFET will not fail again. In addition, several high temperature prevention circuits have been added which will better protect the power supply from overloading and excessive temperatures.

Moving forwards

We always perform significant dynamic testing on chosen power supplies, however in this case we failed to recognize the special conditions and specific loading characteristics the miner would place on the power supply. Our testing has been altered to replicate and include these loading characteristics on any power supplies introduced in the future. Once again, we are sorry.

Latest S4 are running without issues, trusted and serious manufacturer. I purchase and received a pair of batch 11 S3+ miners end of october. Fast shipping and quality product. Running full OC and perform 1TH/s+ ( pair ) on Nicehash pool. S3+ are easier to manage power load. They only require 360W-400W each.