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--- fuss:hardware [2020/06/26 06:57] – [Building a Better NVME Heatsink] office
+++ fuss:hardware [2025/06/25 13:43] (current) – [(Preventively) Fixing a Bloated Phone or Tablet Lithium Battery] office
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-====== VGA Port Dimensions ======
-{{fuss:fuss_hardware_vga_port.png}}
 ====== Removing Superglue from PCBs ======
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 The design is rather simple and consists of an LCD strip and a step-up converter from $5V$ to $12V$ in order to allow the light to be powered via an USB connector. The design can be improved, perhaps by adding an UV light instead of the LCD strip in order to be able to see damages to the board due to capacitor leaks.
+====== Repairing a Broken PCI Bracket ======
+Using some magic putty and a Dremel, a broken PCI bracket can be repaired and seems to hold up to the torque exerted by the screw holding the PCI card in place.
+{{fuss:fuss_hardware_repairing_pci_bracket_inner_view.png?512}}
+The trick is to combine the two substances found in the magic putty and then wait for approximately 12 hours for the curing.
+{{fuss:fuss_hardware_repairing_pci_bracket_side_view.png?512}}
+After the putty has cured, a Dremel can be used to saw off the excess material and drill a hole for the screw to hold the PCI card in place.
+====== USB Pinout ======
+{{fuss:fuss_hardware_usb_pinout.png}}
+====== Jump Start Dead Batteries =======
+TL;DR:
+  * commercial hardware contains battery chargers that are crap,
+  * batteries after a long while loose all the charge (because they're crap, and commercial hardware is crap as well),
+  * battery chargers might not even recognize a fully drained battery,
+  * apply a shock nominal voltage to the battery terminals for just a few seconds to jump-start the battery,
+  * wear protective glasses
+After storing devices with a battery inside for a longer while, due due to passive and residual current flowing through the circuits, batteries tend to be drained completely to the point that even battery chargers will not be able to recharge the battery. For instance, the popular IMAX multi-battery charger and its clones, when connected to the terminals of the battery will report that the connection is broken and will refuse to charge the battery at all, the error message displayed being "Connection break...".
+Furthermore, commercial hardware, as a combination between regulatory (and safety) standards, low power requirements and cheap electronics often bundle a built-in charger that simply is not powerful enough to charge the battery up to its fullest - this is particularly damaging to batteries without memory retention such as LiIon or LiPo where the battery is best maintained charged. The result is that batteries are left in a weak state all the time, most of the time being undercharged and being constantly discharged even passively by residual standby current.
+Assuming that one has access to a battery charger such as the IMAX, a voltage generator and a battery that will not charge, a technique to get the battery jump-started is to apply the battery's nominal voltage using the voltage generator to its terminals for just a few seconds. For instance, for a completely depleted LiPo battery (one good example, the Sony SP73), rated at $1A$ and $4.7V$, apply a current of $4.7V$ to the positive and negative terminals for a few seconds. If an amperemeter is connected in series, one should observe that the battery will start drawing a lot of current from the voltage generator for the duration that the charge is applied to the terminals (for Sony SP73, about $2A$ was observed) such that one must ensure that the application of the charge is short.
+Hopefully, the effect will be that the battery will be charged just enough for the battery charger to pick up the battery voltage and accept to charge the battery.
+This was carried out on a Sony SP73 LiIon battery powering a Sony MX2 that was completely drained to the point that the IMAX charger reported "Connection break..." and refused to charge the battery. However, the same technique should apply perfectly to other battery types as well. Another example is [[/fuss/roomba#fixing_charging_error_onebattery_not_charging|the case of the battery contained within Roomba robots]] that have a base station that is extremely fussy about charging batteries and consistently refuse to charge batteries that are below a certain charge threshold. In the case of the Roomba, fortunately, the IMAX picks up the battery and it does not need to be jump started as per the case of the Sony SP73 battery.
+====== Fix LED Light Strip Connectors ======
+LED strips are usual plastic coated with an underlying layer of copper such that it might happen that connectors like corner converters might have trouble making proper contact with the LED strip copper pads. Identifiable symptoms include segments of the LED strip not displaying the same color as the other segments connected together.
+{{fuss:fuss_hardware_fixing_led_strip_connectors.png?512}}
+Perhaps the easiest solution is to use a solder iron and gently tin the copper pads such that the pins on connectors rest on the ball of solder instead of making a poor connection with the underlying copper pads.
+====== Digital Temperature Unit ======
+Although somewhat misleading, "Digital Temperature Unit" (DTU) refers to a temperature activated fan assembly that can be placed inside a rack in order to provide extra ventilation.
+{{fuss:fuss_hardware_digital_temperature_unit.png}}
+These units are excessively expensive such that [[/fuss/hardware#creating_an_affordable_tray_rack_fan|creating your own tray-based rack fan]] would be preferable. Even so, the DTUs are sometimes provided without a manual such that it takes some extreme guesswork as to what the settings refer to. Aside the clock, which seems easy to figure out, the DTUs have a bunch of settings for fan activation and alarms.
+To program the DTU, long-press the ''Temp'' button and then press the ''Temp'' button in success to scroll through the various DTU settings ''F1'' to ''F6''. The meaning of each setting ''F1'' through ''F6'' is roughly the following:
+^ Program ^ Meaning ^
+| ''F1'' | The fan activation temperature. |
+| ''F2'' | The fan shutdown temperature. |
+| ''F3'' | Temperature sensor calibration (better left at ''0'' unless otherwise determined). |
+| ''F4'' | Unused (set to ''0''). |
+| ''F5'' | Acoustic alarm (buzzer) after exceeding ''F1''. The value ''0'' means no acoustic alarm. |
+| ''F6'' | Alarm delay after exceeding the preset temperature of ''F1''. |
+These settings seem to apply more or less universally to all DTUs out there.
+====== Applying Thermal Paste to CPUs (The Cross Technique) ======
+Thermal paste is meant to make a connection between a CPU and a heatsink by using surface tension to create an air-tight area between the CPU and the heatsink that allows the transfer of heat efficiently.
+One technique for applying thermal paste is to spread two lines of paste in a cross shape across the CPU and then use a flat shim in order to spread the paste both horizontally and vertically till the entire top part of the CPU is coated in thermal paste.
+{{fuss:fuss_hardware_applying_thermal_paste_to_cpus_the_cross_technique.png?512}}
+Thermal paste unfortunately tends to dry up over time even if it is deliberately designed not to such that periodic reapplication of thermal paste is necessary in order to ensure that there is proper heat transfer from the CPU. The image displayed above shows the result of neglecting periodic applications of thermal paste where the upper part of the CPU displays a white mud-like formation that is dried up and solid.
+It is not necessary to apply a large amount of paste and bear in mind that the main purpose of the thermal paste is to create an air-tight contact and that the heatsink itself is the main heat dissipatior but not the paste. That being said, a common mistake is to apply lots of paste rather than just covering the CPU with a thin coat.
+====== Creating a 6pin mini-DIN Gender Changer Dongle ======
+A 6pin mini-DIN gender changer dongle is useful when you have a cable with both genders on either end but need to connect two devices with the same gender. 6pin mini-DIN sockets are very well known due to the socket being identical to the PS/2 mice and keyboards that are universally available in all stores. In fact, in order to create the dongle the cable is cut off two mice.
+In order to create a compact dongle without using extra cabling, the two male sockets are soldered on top of each other, pin-to-pin straight-through and with a single copper wire to connect the external shielding / ground of the sockets together.
+{{fuss:fuss_hardware_6pin_mini_din_gender_changer.png?512}}
+Using a small tip solder, the pins can be soldered together fairly easily and it seems that the sockets form a strong bond.
+To finalize the dongle, both sockets are wrapped in painter tape after soldering in order to create a mold or form, and then hot-melt glue is poured on top to cover up the soldered pins and the external copper wire. After the hot-melt glue cools off, the excess plastic is sawed off using a cutter in order to leave just the bare minimal that hides the pins and the shield wire.
+{{fuss:fuss_hardware_6pin_mini_din_gender_changer_hot-melt_glue.png?512}}
+The 6pin mini-DIN has applications in HAM radio, in particular pertaining to [[fuss/radio/ham/yaesu/ft-891|Yaesu radios]] that typically use mini-DIN sockets for digital modes and data transfer. In particular, the 6pin mini-DIN gender changer has been created in order to supplement the [[/ham_radio/designing_a_vox_sound_input_for_ham_radios#redesign_rebuild_and_remake|remake of the VOX sound injector for the Yaesu HAM radio]].
+====== Creating an Ultra-Compact Charger ======
+If the recharge circuit of a device is to be found within the device, then a device can be charged simply by providing the necessary voltage to the input port of the device. Unfortunately, $220V$ AC to $5V$ DC converters are fairly large and can be somewhat reduced if one removes some of the plastic in order to create a compact charger.
+The first step is to find and remove the pins of a wall socket and that can be a nasty business that does not look very pretty.
+{{fuss:fuss_hardware_creating_an_ultra_compact_charger_salvaging_plug.png?512}}
+With the pins removed however, the pins can be mounted onto a PCB, that will then be filed down to a minimal size.
+{{fuss:fuss_hardware_creating_an_ultra_compact_charger_mounting_pins_on_pcb.png?512}}
+In order to ensure some safety, the PCB is then wrapped in JB weld, by covering the pins and the exposed PCB and then letting the improvised socket pins dry.
+{{fuss:fuss_hardware_creating_an_ultra_compact_charger_isolation.png?512}}
+The final build then just consists in the socket pins mounted onto the PCB, a mini $220V$ AC to $5V$ DC stepdown converter and an USB socket that is salvaged from an USB cable. The result is much more compact and can be tucked into small pockets if need be and it will provide the necessary power to charge the battery within a lithium-powered USB device.
+====== Repurposing a Charger with Wrong Socket Pins ======
+One interesting technique in using hot melt glue is to create a mold using painter's tape in order to isolate or cover something up to the point of obtaining a result that matches the overall blocky allure of the item built upon.
+In this situation, a charger with U.S. pins can be repurposed nicely by connecting mains leads to both pins and then surrounding the result with painter's tape.
+{{fuss_hardware_repurposing_a_mismatched_socket_adaptor_painter_tape.png?512}}
+After that, a stick of hot melt glue (plastic) is heated up using a heat gun and the glue is left to drip into the small mold created by the painter's tape. When the glue fills up all the way to the top, some time is given to the item to cool down, after which the painter tape can be removed.
+{{fuss:fuss_hardware_repurposing_a_mismatched_socket_adaptor_hot_melt_glue.png?512}}
+With the tape removed the result will be something in-line with the overall aspect of the charger that can also incidentally be easily removed without disturbing the soldered wires.