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Quantum LTO2 CL1001 Tape Drive Teardown

Drive Top
Drive Top

I have recently begun to create an archive of all my personal data, and since LTO2 tape drives offer significant capacity (200GB/400GB) per tape, longevity is very high (up to 30 years in archive), & relatively low cost, this is the technology I’ve chosen to use for my long term archiving needs.

Unfortunately, this drive was DOA, due to being dropped in shipping. This drop broke the SCSI LVD connector on the back of the unit, & bent the frame, as can be seen below.

Broken SCSI
Broken SCSI

As this drive is unusable, it made for a good teardown candidate.

Cover Removed
Cover Removed

Here the top cover of the drive has been removed, showing the top of the main logic PCB. The large silver IC in the top corner is the main CPU for the drive. It’s a custom part, but it does have an ARM core.

The two Hitachi ICs are the R/W head interface chipset, while the smaller LSI IC is the SCSI controller.
The tape transport & loading mech can be seen in the lower half of the picture.

Main Logic
Main Logic

Close up of the main logic.

Tape Spool
Tape Spool

Here the main logic PCB has been removed, showing the tape take up spool. The data cartridges have only one spool to make the size smaller. When the tape is loaded, the drive grabs onto the leader pin at the end of the tape & feeds it onto this spool.
The head assembly is just above the spool.

Bottom Plate Removed
Bottom Plate Removed

Bottom of the drive with the cover plate removed. Here the spindle drive motors are visible, both brushless 3-Phase units. Both of these motors are driven by a single controller IC on the other side of the lower logic PCB.

Head Drive Motor
Head Drive Motor

The head is moved up & down the face of the tape by this stepper motor for coarse control, while fine control is provided by a voice coil assembly buried inside the head mount.

Tape Head Assembly
Tape Head Assembly

The face of the tape R/W head. This unit contains 2 sets of 8 heads, one of which writes to the tape, the other then reads the written data back right after to verify integrity.

Cartridge Load Motor
Cartridge Load Motor

The tape cartridge loading motor. I originally thought that this was a standard brushed motor, but it has a ribbon cable emerging, this must be some sort of brushless arrangement.

A replacement drive is on the way, I shall be documenting some more of my archiving efforts & system setup once that unit arrives.

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AD9850 DDS VFO PCB & Schematic Layout

I recently came across a design for an Arduino controlled AD9850 DDS module, created by AD7C, so I figured I would release my Eagle CAD design for the PCB here.

It is a mainly single-sided layout, only a few links on the top side are needed so this is easy to etch with the toner transfer method.

My version uses an Arduino Pro Mini, as the modular format is much easier to work with than a bare ATMega 328.

RF output is via a SMA connector & has a built in amplifier to compensate for the low level generated by the DDS Module.

DDS VFO
DDS VFO

Version 2 Update: Added reverse polarity protection, added power indicator LED, beefed up tracks around the DC Jack.
[download id=”5571″]

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Potentially Lethal Clone Apple Charger

Charger
Charger

I received this USB supply with a laser module from China that I purchased on eBay. I have heard of these nasty copies of Apple chargers going around, but I’d never received one this bad with a piece of Chinese electronics.

Label
Label

Model No. A1265, so definitely an Apple clone. Apparently capable of +5v DC 1A output. Notice the American NEMA pins. This wouldn’t have been any use to me in the first instance since I am resident in the UK & our mains plugs are significantly different, not to mention significantly safer.

Manufacturer is marked as Flextronics.

Top Of Boards
Top Of Boards

Here is the charger disassembled. Inside the case these two boards are folded together, creating an alarmingly small isolation gap between the mains side of the supply & the 5v output. Both the low voltage output & the feedback loop for the supply runs over the 4-core ribbon cable.
The mains wiring from the board is as thin as hair, insulation included, so there is a big possibility of shorts all over the place from this part of the circuit alone.

Bottom Of Boards
Bottom Of Boards

Bottom of the PCB assemblies. Good luck finding any creepage distance here. There simply isn’t any at all. traces on the +350v DC rail on the mains side of the transformer are no more than 1mm away from the supposedly isolated low voltage side.

Plugging one of these devices into anything is just asking for electrocution.

 

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Solar Cable Upgrade & Pseudo-MPPT

New Cable
New Cable

As the cable supplied with the panel is far too short, inflexible & does not even allow the cable gland on the terminal box to form a seal, I have replaced it with some high quality twin core guitar cable, with silicone insulation.

The cable is removable from the panel tail by means of a screwlock two pin connector.

 

On another note, I have noticed a side effect of fitting a switchmode regulator to the panel: it seems to have formed an MPPT-type regulator setup, as even in low light conditions, when the bare panel is outputting 18.5v at 50mA short circuit, with the switching regulator I can get a useable 13.25v at ~170mA.
This effect is increased in full light, where I can obtain 4.5A short circuit current & ~1.8A at 13.25v output.

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Media PC Build Log

Front
Front

This will be the record of building a new Media PC, above you can see the finished system.

It’s Mini-ITX based, with on-board HDMI output, specifically to run XBMC via Fedora for media purposes.

CiC MTX001B Mini-ITX Case
CiC MTX001B Mini-ITX Case

This is the case that is being used, around the size of a Shuttle PC. It has a single 3.5″ & 5 1/4″ bay, for a HDD & ODD, front panel USB, Firewire & Audio.

Intel BLKDH57JG Mini-ITX Motherboard
Intel BLKDH57JG Mini-ITX Motherboard

Motherboard to fit the case. Supports Intel Core i5 series CPUs, with up to 8GB of DDR3 RAM.
Other features are on-board full surround audio, HDMI, eSATA, & a single 16x PCIe slot.

Corsair 4GB DDR3 DIMMs
Corsair 4GB DDR3 DIMMs

Matching memory for the motherboard, a pair of 4GB DDR3 units.

Akasa K25 Low Profile CPU Cooler
Akasa K25 Low Profile CPU Cooler

Having never been impressed by bundled coolers with CPUs, here is an aftermarket low-profile unit, with solid copper core for enhanced cooling. This cooler is specially designed for Mini-ITX uses.

Intel Core i5 650 Dual Core 3.2GHz CPU
Intel Core i5 650 Dual Core 3.2GHz CPU

The brains of the operation, Core i5 650 CPU, should handle HD video well.

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Raspberry Pi GPIO Breakout

Board Built
Board Built

After seeing these on eBay for £8.99 I thought it might be a good deal – interfacing with the RasPi’s GPIO & it has built in power supplies.

As a kit, it was very easy to assemble, the PCB quality is high, and is a fairly good design. It worked first time, the regulators hold the rails at the right voltages.
However there are some issues with this board that bug me.

The documentation for the kit is *AWFUL*. No mention of the regulators on the parts list & which goes where – I had to carefully examine the schematics to find out those details.
The 4x 1N1007 diodes required weren’t even included in the kit! Luckily I had some 1N4148 high speed diodes lying around & even though they’re rated for 200mA continuous rather than the specified part’s 1A rating, the lack of heatsinking on the regulators wouldn’t allow use anywhere near 1A, so this isn’t much of a problem.

Component numbering on the silkscreen isn’t consistent – it jumps from R3 straight to R6! These issues could be slightly confusing for the novice builder, and considering the demographic of the RasPi, could be seen as big issues.

On the far left of the board are the 5v & 3.3v regulators, well placed on the edge of the board in case a heatsink may be required in the future. However the LM317 adjustable regulator is stuck right in the middle of the PCB – no chance of being able to fit a heatsink, & the device itself seems incredibly cheap – the heatsink tab on the back of the TO-220 is the thinnest I have ever seen. Not the usual 2-3mm thick copper of the 5v & 3.3v parts – but barely more than a mm thick, so it’s not going to be able to cope with much power dissipation without overheating quickly.

As the adjustable rail can go between ~2.5v – 10v, at the low end of the range the power dissipation is going to shoot through the roof.

The GPIO connector – this could have been done the other way, at the moment the ribbon cable has to be twisted to get both the Pi & the GPIO board the same way up. Just a slight fail there. See the image below

Plugged In
Plugged In

The power rails are not isolated out of the box – there is no connection between the 5v & 3.3v rails & the Pi’s GPIO, but the GND connections are linked together on the board.

Getting the ribbon cable through the  hole in the ModMyPi case was a bit of a faff – the connector is too big! I had to squeeze the connector through at a 45° angle. The case is also remarkably tight around the connector once it’s fitted to the board – clearly the designers of the case didn’t test the an IDC connector in the case before making them!
Everything does fit though, after a little modification.

All Cased Up
All Cased Up

Here is the unit all built up with the case. The top cover just about fits with the IDC connector on the GPIO header.

More to come once I get some time to do some interfacing!

 

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LED Lighting Part 1

Here I will document progress in replacing standard halogen MR10 lights with LEDs.

3x1W LED
3x1W LED

These units are from TruOpto, available through Rapid Electronics in the UK. They are 3W total, from 3x 1W emitters on an aluminium back plate.

LED Test Rig
LED Test Rig

Here is the LED attached to a heatsink for testing purposes – these units dissipate nearly 2W in heat at full output.

As the lights are to be run from a 12v battery bank, for simplicity a master regulator is required to provide a stable 11.4v rail for LED supply.

Regulator Module
Regulator Module

I have used a Texas Instruments part – PTN78020WAH. This is a 6A capable adjustable regulator module.

The LED lights are to be fully dimmable – the low voltage PWM dimmers are in progress of being built.

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PSi 150 Power Inverter

Front
Front

This is a small 120W power inverter, intended for small loads such as lights, fans, small TVs & laptop computers.

End Cover
End Cover

End cover of the unit, 12v DC input cord at the top, power switch & indicator LEDs at the bottom.

Mains Output
Mains Output

Opposite end of the unit, with the standard 240v AC 50Hz Mains output socket.

Cover Removed
Cover Removed

Cover removed from the top of the unit. Main power transformer is visible in the centre here, MOSFET bank is under the steel clamp on the left, the aluminium case forms the heatsink.

PWM Controllers
PWM Controllers

On the right is a KA3525 switchmode PWM controller & on the left is a LM324N quad Op-Amp IC. The buzzer on the far left is for the low battery warning.

PCB Removed
PCB Removed

PCB removed from the casing, with the MOSFET bank on the right hand side. Two potentiometers in the centre of the board tweak the frequency of the switcher & the output voltage.

 

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Belling Microwave


Front
Front

Here is a cheap no frills microwave oven, which died after a few weeks of normal use.

Electronics Bay
Electronics Bay

Cover removed, showing the internals. Front of the microwave is on the left.

Timer
Timer

Closeup of the timer unit. Cheap & nasty.

Magnetron
Magnetron

Magnetron removed from the oven. Antenna is on the top,  cooling fins visible in the center. White conector at the bottom is the filament terminals.

Magnetron Chokes
Magnetron Chokes

Chokes on the magnetron’s filament connections. These prevent microwave energy from feeding back into the electronics bay through the connections.

Magnetron Assembly
Magnetron Assembly

Magnetron cooling fins, tube & magnets removed from the frame.

Magnetron Tube
Magnetron Tube

Bare magnetron tube.

Power Input Board
Power Input Board

This PCB does some rudimentary power conditioning, power resistors are in series with the live feed to the power trasformer, to prevent huge power up surge. When the transformer energizes the relay, which is in parallel with the resistors, switches them out a fraction of a second after, providing full power to the transformer.
Standard RFI choke & capacitor at the top of the board, with the input resistor.

Transformer
Transformer

Power transformer to supply the magnetron with high voltage.
Power output is ~2kV at ~0.5A. Pair of spade terminals are the low voltage filament winding.

Capacitor
Capacitor

HV Capacitor. This along with the diode form a voltage doubler, to provide the magnetron with ~4kV DC.

Diode
Diode

HV diode stack.

Fuse Element
Fuse Element

Internals of the HV fuse. Rated for ~0.75A at 5kV. The fuse element is barely visible attached to the end of the spring. Connects between the transformer & the capacitor.

Cooling Fan
Cooling Fan

Cooling fan for the magnetron. Drive is cheap shaded pole motor.

Fan Motor
Fan Motor

Fan motor. Basic 240v shaded pole induction type.

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Hair Dryer

Housing
Housing

This is a 1500W hairdryer, death caused by thermal switch failure.

Switch
Switch

This is the switch unit. Attached are two suppression capacitors & a blocking diode. Cold switch is on right.

Heating Element
Heating Element

Heating element unit removed from housing. Coils of Nichrome wire heat the air passing through the dryer. Fan unit is on right.

Thermal Switch
Thermal Switch

Other side of the heating element unit, here can be seen the thermal switch behind the element winding. (Black square object).

Fan Motor
Fan Motor

The fan motor in this dryer is a low voltage DC unit, powered through a resistor formed by part of the heating element to drop the voltage to around 12-24v. Mounted on the back of the motor here is a rectifier assembly. Guide vanes are visible around the motor, to straighten the airflow from the fan blades.

Fan
Fan

5-blade fan forces air through the element at high speed. Designed to rotate at around 13,000RPM.