Example Lids as Circuit Boards (PCB) Part 2

Summary
This short blog follows on from the previous blog listing some drawings for lids/plates that were replaced with circuit boards.

Hammond 1455N1601 with Press Fit Panel

Circuit Boards Lids
While the previous blog used a clearance of at least 0.1 mm per edge, some of the new lids used an interference fit. Board dimensions should be validated to suit each design.

Again for verification, the Altium Designer files were saved as STEP files, converted to STL files then 3D printed before manufactured.

The DXF files below were generated using the Export feature in Altium Designer. The listed DXF files can be imported into an Altium PCB project using measurements in millimetres.

PCB Lid DXF for NUB505017

Datasheet for NUB505017

 

PCB Lid DXF for PJ110706

Datasheet for PJ110706

 

 

PCB Lid DXF for BIM200424

Datasheet for BIM200424
 

PCB Lid DXF for 1455N1601

Datasheet for 1455N1601

PSU Repair JT-DC12C5A

Summary
This blog details the repair of a JT-DC12C5A(II)-A switch-mode power supply.

JT-DC12C5A Power Supply

 
Details
The switch mode power supply displayed above had been operating under high load for an extended period before failure. After failure, the DC 12 V output had reduced to less than DC 2 V.

Disassembly
Note: For repair to any AC 240 V equipment, due care and attention should be taken before undertaking service work or repairs. Unplug equipment before performing repairs!

Four plastic clips are integrated into the housing and one plastic screw hold the two-piece enclosure together.

After prying the case apart, the power supply circuit board was attached to the enclosure base plate.

JT-DC12C5A Circuit Board

Servicing
A quick visual inspection of the board did not identify any burnt or charred sections on the PCB. The mains fuse continuity was good.

A slight bulge was noticed in one of the electrolytic capacitors located on the DC output stage. As shown in the image below, the top portion of the leftmost electrolytic capacitor is bowed upwards.

JT-DC12C5A Bulged Capacitor

The suspect capacitor was unsoldered from the power supply PCB and checked with a capacitance meter. The measured capacitance was 1 nF where the capacity listed on the case was 470 uF.

JT-DC12C5A Replaced Capacitor

A capacitor with a larger capacity of 2200 uF and the same working voltage was fitted to the circuit board.

The unit was powered and a 2 A load was fitted to the output. Measuring the output voltage with the load was approximately DC 12.1 V.

JT-DC12C5A Output Load Test Measurements

The unit was reassembled and another load test was conducted at around 4 A. Operation was verified by measuring the output voltage, approximately DC 12 V.

Summary
As far as power supply circuit boards repairs rate, this was uncomplicated. However, the change to the output capacitor was made to address possible ripple currents in the output that may have damaged the smaller capacitor. As always, the component specifications should be verified before replacing in any repair.

Electronic Component Reel Clip

Summary
This blog provides a solution to tidy partially consumed electronic component reel/spool tape using a 3D-printed clip.

Clip for Electronic Component Reel

On-Reel Clip
For infrequently used component reels, an on-reel clip can be attached as shown above to secure the tape. The 3D-printed clip features a slot through the clip body for securing the tape. This prevents the unnecessary unwinding of a reel when stored.

Loose Component Reels

Reel Types
Component reels come in various diameters and packaging which can result in different spool characteristics. The clip dimensions were adjusted to suit different for suppliers such as Multicomp Pro, Philips, Yageo, Vishay, Wurth and likely more manufacturers.

For this blog, two reel types were used. The more common reel uses a thin or narrow reel frame and others had a thicker frame. Narrow clips use a 1.2 mm gap and Wide use a 1.9 mm gap to clip over the reels as illustrated below.

Closeup of Fitted Clip

Reel Clips
To assist in identifying the type of components on a reel, the first letter of the component was embossed on the outside face of the clip. R for resistor, C for a capacitor and a generic N for no marking.

The printed clips used a 0.16 mm printer resolution, material was PLA+, no raft and no supports.

3D Model of Component Clip

Downloads
These files are free for personal use.

Reel Clip - Narrow - None

Reel Clip - Narrow - Capacitor

 

Reel Clip - Narrow - Resistor

 

Reel Clip - Wide - None

 

Reel Clip - Wide - Capacitor

 

Reel Clip - Wide - Resistor

Salvaging Motorola MBP11

Summary
This blog performs a teardown of the Motorola MBP11 baby monitor, comprised of a transmitter and receiver unit, for the purpose of salvaging electronics.

Original Image Motorola MBP11 (Rights reserved)

Dismantling
The receiver unit of the MBP11 was commonly battery powered by a small NiMH battery. Removing the battery cover allowed access to two plastic screws holding the two-part case together. Whilst the battery could be salvaged, the battery chemistry and capacity may limit use.
For the MBP11 transmitter unit, the two plastic screws holding the case together were accessible from the rear of the unit.
Removing one side of the plastic housing provided access to the circuit boards as shown below.

Opened Cases of Motorola MBP11 Units

Receiver Unit
Holding the receiver circuit board in position were additional plastic screws. The speaker connections were disconnected when the half plastic cases were brought apart.

Located on the circuit board were only a handful of salvageable items. The processor was the usual ‘blob’ solution and the RF was all handled in a metal can fitted to a castellated daughter board.

The orange box in the image below shows the 13.842 MHz surface mount crystal used by the unit.

Identified in the yellow box, a serial memory device. The FRAM serial memory part FM24C16B would be worth salvaging especially due to the long data retention of FRAM.

Motorola MBP11 Receiver Circuit Board

Connectors shown by the purple box may come in handy if the battery or external DC 6 V plug pack were used for another purpose.

Out of curiosity the metal can on the castellated RF board was removed.

Under the RF Can on the MBP11 Receiver Circuit Board

Under the metal can was an RF chip, DE 19RF 19CNC, from a chip manufacturer called DSP Group. No immediate datasheet could be located for the chip.

Although the RF chip may not be worth salvaging, the implementation behind the castellated daughterboard is a good example of what can be achieved especially with RF.

There are a few takeaways for new circuit board designers attempting castellated boards including items such as the castellated pad spacing, RF shielding and component placement. As an example, shown by the red box in the image below, the power rail (one side) was decoupled on the main circuit board immediately after the via, then at the RF chip itself.

Decoupled Power Highlighted for Receiver Castellated Circuit Board

There were seven LED's on the rear of the circuit board that could also be salvaged. Five LED's provided visual feedback for the sound level detected and the remaining indicating connectivity and power. Worth salvaging just for prototype boards.

LED's on MBP11 Receiver Circuit Board

Transmitter Unit
Similar to the receiver unit, the transmitter circuit board was held in position were two additional plastic screws.

The same ‘blob’ solution and RF in a metal can was present on the transmitter board with no castellated circuit board.

The orange box showed the same 13.842 MHz surface mount crystal as the receiver and the yellow box shows the same FRAM device.

Identified by the purple box was the power connector jack.

Motorola MBP11 Transmitter Circuit Board

Highlighted by the black box, the solitary surface mount capacitor. Manufacturer unknown.

Additionally, a linear regulator was present on the transmitter. The red box shows the LM1117. This device could be salvaged also.

The metal can was removed to show the same RF chip as the receiver unit, DE 19RF 19CNC.

Under the RF Can on the MBP11 Transmitter Circuit Board

For both boards, the leaded electrolytic capacitors showed no signs of wear and could be salvaged if needed. All manufacturers of these electrolytic capacitors are not well known. However, some devices are rated to 105°C. Similarly, there are dozens of passive components on the board that could be pried off if required.

Additional Salvaged Items

 

There were additional items such as the PCB mount microphone, external speaker, metal clip and springs that could come in useful for a variety of jobs.

Final Thoughts
There were further items to keep in mind regarding the technology used by these circuit boards such as the gratuitous use of test points, the practical use of via stitching in the RF area and associated power traces.

One item of caution however was the lack of Lead-Free marking on the circuit boards. For the intended target market of the Motorola MBP11, Lead-free would be no less than expected. However, as Lead-free was not noted on the circuit boards, for those salvaging from this or any such device, the appropriate preventatives should be taken.

Example Lids as Circuit Boards (PCB)

Summary
This short blog lists a handful of drawings for lids/plates of instrument cases that were replaced with circuit boards.

Example Project using 3D Printed PCB Panel (Multicomp MC002212)

Front Plates as Circuit Boards
The lid or plate on an instrument case is commonly manufactured as a plastic such as ABS, diecast aluminium or steel. These can be readily be replaced with a circuit board. Some of the benefits and drawbacks of using the circuit board are listed below.

1. Customised appearance and colour in a single process (no separate decal or printing),
2. Electronics can be added to the circuit board providing additional real estate,
3. Circuit board may have benefits for EMC compared to standard plastic items (not metal screened),
4. Minimal to no machining or manufacturing work for the circuit board,
5. Iterating circuit board designs may end up faster than updating CAD for metal lids or plates,
6. Plastic or metal lid or plate becomes waste or at best recycled if not used,
7. Reworking a circuit board for mechanical purposes is not always possible,
   
8. Circuit boards usually require more processes to recycle.

Example Lids as Circuit Boards
Shown below is a generic plastic enclosure called a jiffy box with a 3D plastic lids designed in Altium. 

A clearance of at least 0.1 mm per edge was chosen however the clearance should be adjusted as required due to variations in manufacturing.

Jiffy Box with 3D Printed PCB Plate

 
For verification, the Altium Designer files were saved as STEP files, converted to STL files then 3D printed. The files below were generated as DXF files using the Export feature in Altium designer. These DXF files can be imported into an Altium PCB, using a measurement in millimeters with the board shape defined on Mechanical-1.

PCB Lid DXF for Jiffy Box UB3

 

PCB Lid DXF for Jiffy Box UB5

PCB Lid for Hammond (Eddystone) 27969PS

PCB Lid for Multicomp (Element14) MC002212

 

Salvaging Swann DVR SWDVR-81500H

Summary
This blog details the salvaging process of hardware from a Swann DVR, model SWDVR-81500H and an associated dome camera.

Swann DVR

DVR
The Swann DVR unit was factory supplied with an external power supply and several dome cameras. This unit in this post was a superseded model.

Swann DVR Rear Plate

On the backplate of the DVR were inputs for the dome video cameras, audio inputs, video out, power, LAN and USB connections.

Swann DVR Internals

To open the DVR unit, four plastic screws in the base were removed. Upon sliding the metal plate away from the ABS case, the controller card and hard drive were visible.

The white ABS case was relatively sturdy and could be repurposed for another custom project. Similarly, the metal frame could be repurposed.

Hardware
The hard drive was held on with an additional four screws and easily removed. Manufactured by Western Digital, for this model DVR a 500 GB HDD was fitted. The drive could be reused; reformatting and standard SMART hard drive tests would be recommended.

Short Hard Drive Cables

The hard drives short serial ATA cable and power could be salvaged for another Single Board Computer (SBC) project.

To remove the controller board the screws in the metal base and backplate were removed.

Controller Card Components
Depending on the requirements of the salvager, most of the connectors from the controller board could be repurposed. The BNC connectors were sturdy and come with the right angle PCB mounting brackets. Most of the connectors were unbranded so cross-referencing against standard PCB footprints would be recommended for consistency and availability.

DVR Controller Board

 
Other parts such as the Piezo buzzer and CR1220 surface mount battery holder (yellow box in the above image) are readily salvaged.

Some of the electrolytic capacitors close to the DC input power jack were showing early signs failure with bulging at the top of the can.

The crystals, inductors, processor heatsink and LED's can readily be removed for salvage.

The controller was manufactured by HIKVision and the associated DDR3 memory (128M x 16) was from Samsung, part K4B2G1646F-BCK0 (blue box).

Processor Heatsink

The controller was manufactured by HIKVision and the associated DDR3 memory (128M x 16) was from Samsung, part K4B2G1646F-BCK0 (blue box).

HIKVision Processor Cover

These parts were not worth removing unless required to repair another unit or similar DVR; the usual removal method would be via a hot air tool.

For the video decoding, an Intersil (Renesas) TW2968 8-channel video/audio decoder (orange box) was used by the DVR, likely not useable.

Ethernet communications utilised the Realtek 10/100 PHY, RTL8201F (purple box). Similar part here. The Ethernet chip supports the standard communications modes except RGMII. Could be salvaged using the correct tools however Gigabit devices are more common.

For timekeeping, an NXP RTC PCF8563 on the rear of the board was used. The RTC has a standard SOIC footprint which is worth salvaging with the battery holder (yellow box ) for a project requiring an RTC.

Lastly, the DC 12 V 2 A plug packs powering the DVR were in reasonable condition, with a larger style DC jack; worth keeping as spares.

Camera Hardware
The associated DVR dome camera presented as a sealed unit. The body of the camera was produced from diecast aluminium.

Dome Camera

After removing the dome camera from the plastic roof mount, three screws were visible on the rear of the camera. Removing the screws on the rear allowed the cover containing the glass window to be taken off.

Dome Camera Opened

Looking at the internals of the camera, the LED ring is immediately visible. Removing the two retaining screws and the connecting cable allowed the LED ring to be removed.

Dome Camera LED Ring

The twenty-four IR LED’s fitted to the PCB could be salvaged. However, the board is a self-contained circuit, with a light sensor and LED driver which may suit a project requiring IR illumination without modifications.

Dome Camera LED Ring Rear

Holding the camera board to the diecast aluminium base were M2.5 bolts and M2.5 x 13.5 mm Hex metal spacers. The two halves of the dome camera could be repurposed for another camera project.

Dome Camera Board

The camera board contained a day-night switch which was achieved using a mechanical assembly.

Camera Day-Night and Lens Assembly

This assembly also contained the camera lens. Driving the day-night switch solenoid was a Unisonic reversible motor driver BA6208.

Camera Board Front

Removing the camera chip would be possible, however desoldering all four sides of the device usually requires dedicated equipment or patience.

Camera Board Rear

Interfacing to the camera chip and controlling the solenoid for day-night operation was an ST microcontroller, part STM8S003F3P6. With 8k of FLASH memory and a small amount of EEPROM, this could also be salvaged.

The switch-mode power supply manufacturer was not identifiable.

The remaining parts such as the 27 MHz crystal, inductor and surface mount connectors (reasonable quality) could also be salvaged.

Other items such as the BNC adaptors and interconnecting cables between the DVR and dome cameras were not worth salvaging.