BatteryShark UPS Battery Failures

Posted in Uncategorized on December 29, 2015 by brandon314

Fully charged 48 volt pack in an APC DLA3000RM2U. Individual measurements made on pack with light load. The two cells marked with “X” are failed badly and there is a 3rd weak cell. Weak/failed cells were moved to one series string upon discovery so that the UPS would pass a self-test without shutting completely down and risking system shutdown.

Batteries are <12mo old and have <5min of cumulative draw on them. Float charge voltage shown in last photo. System runs with 9-11% load.

Cell 1 – 12.20V

IMG_20151229_011117

Cell 2 – 12.12V

 

 

 

IMG_20151229_011109

Cell 3 – 12.11V

IMG_20151229_011055

Cell 4 – 12.19V

IMG_20151229_011044

Cell 5 (weak) – 11.88V

IMG_20151229_011006

Cell 6 (failed) – 9.47V

IMG_20151229_010957

Cell 7 – 12.09V

IMG_20151229_010947

Cell 8 (failed) – 9.41V

IMG_20151229_010855

Pack voltage back on-charge (54.5V)

IMG_20151229_011426

Dickbutt .stl 3D Printing Files

Posted in 3D Printing on December 8, 2015 by brandon314

These were harvested from various sources that no longer allow them. Cudos to the rightful owners…may your legacy live on!

Hosted on google-drive.

dickbutt.zip has all the .stl files I have within. Chess Set pieces and a dickbutt 2D -> 3D conversion.

Cheers!

https://drive.google.com/file/d/0Bx_qKzyNetMDRi1lSUNnXzh1RGc/view?usp=sharing

Decoding Chinese RFID Ebay Auctions

Posted in Electronic Projects, Part Research, Reviews with tags , , , , , on March 20, 2014 by brandon314

Some very basic (but very useful) notes regarding RFID products on Chinese ebay auctions for RFID readers. This includes wiegand receivers. This is mainly for the cheap RFID readers/cards/etc. found on e-bay.

  • If it says “ID” anywhere in the ad, 125Khz
  • If it says “IC” anywhere in the ad, 13.56Mhz.

The standards listed (14443A, M1Card, etc.) are used randomly even though the devices may not be compatible. It appears the fall-back is the ID/IC standard for whether your card is LF or HF. The likelihood of a dual-band reader existing on ebay is VERY VERY slim.

 

Ubiquti AirCAM Repair – Link but no GUI

Posted in Electronic Projects with tags , , , on October 25, 2013 by brandon314

Hello all,

Quick note over here from the world of failing AirCAM’s. I recently had a 2nd failure of my exterior mounted AirCAM. Since the RMA process was coming up bunk I decided to attempt a repair myself. I run an electronics engineering lab so have access to equipment (hot-air reflow, metcals, etc.)

The camera under repair is one I had die in operation about about 3mo of continuous use. The camera was exhibiting a condition where it would link up (sometimes at 100BaseT, always at 10BaseT) but I could never reach the GUI or do anything but SOMETIMES ping the unit (192.168.1.20). Flexing the PCB or agitating the camera didn’t seem to make a difference.

I opened up the camera (quite easy) buy removing the sun shield, unscrewing the lens cover, popping off the triangular face ring, and removing the black screws. Once removed, I could slide the camera/PCB board out of the body and engage in repair activities. The PCB/components are coated with what I suspect is an anti-moisture protector so make sure you have adequate airflow when doing any heating of the PCB.

Image

Image

Image

I reflowed the small BGA package (U3) and touched the rest of the board with the hot air JUST in case there was a poor lead-free solder connection. Once reflowed, the camera snapped back to life (able to access the GUI, etc.)

As I’ve had issues with BGA components before (especially when using lead-free solder) I am not terribly surprised to see problems here. I’m happy to see that static electricity didn’t kill this device (apparently that is another common failure). My last camera would transit packets but not receive them (similar issue?)

Interesting side note that the device PCB has a USB connector site that can be populated. Not sure what for, but it’s there.

Hopefully these notes treat someone well. If you don’t have access to the right tools, I can help re-flow your failed AirCAM (if out of warranty) as a last resort. Contact me for details.

Icom W32A Handheld Manual

Posted in Manuals, RF on May 21, 2013 by brandon314

ICOM_W32A_Manual

Basic Battery Isolation Using Solenoid

Posted in Automotive, Electronic Projects, Power on April 29, 2013 by brandon314

Dual Battery Isolater

Glenn Martin MT-1845 Tower Documentation

Posted in Infrastructure, Manuals, RF on April 3, 2013 by brandon314

I had a difficult time finding this documentation so I’ll post it here for anyone whom may need it in the future.

 

This is for a Glen-Martin (G-M) MT-1845 50ft crank-up ground-mount tower. This is the same tower found on their TT-1845 (trailer mounted 50ft tilt over tower), but with a base plate for direct ground mounting.

PDF Document for Base Plate/Concrete Requirements: Chb13-18

PDF Document for Tower Specification Drawings: MT-1845

 

HB-13-18

MT-1845 1

MT-1845 2

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