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Bargain Bin USB-ODB Interface

ODB Adaptor
ODB Adaptor

This is a little bit of kit I got to talk to the Webasto TT-V I salvaged from a scrap Jaguar S-Type, and converts USB-RS232 to the standard car diagnostic ODB connector. (These are a much cheaper option at £4 than the official Webasto diagnostic adaptor & loom which is over £90.

PCB Top
PCB Top

There’s really not much to this adaptor, the only signals that are routed to the ODB connector seem to be the +12v on pin 16, K-Line on Pin 7 & L-Line on pin 15. The main IC here is a CH340 USB-Serial interface, with some glue logic in the form of an LM339 quad comparator.

PCB Reverse
PCB Reverse

The reverse side of the PCB only has the power indicator LED.

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Jaguar S-Type Aux Heater / Webasto Thermo Top V Part 1 – Teardown & Cleaning

Jag Label
Jag Label

Here’s another Diesel-fired heater related project – these Webasto heaters are fitted to Jaguar S-Type cars as auxiliary heaters, since (according to the Jag manual), the modern fuel-efficient diesels produce so little waste heat that extra help is required to run the car’s climate control system. (Although this seems to nullify any fuel efficiency boost, as the fuel saved by not producing so much waste heat in the engine itself is burned in an aux heater to provide heat anyway). The unfortunate part is these units don’t respond to applying +12v to Pin 1 of the ECU to get them to start – they are programmed to respond to CAN Bus & K-Line Bus only, so they require a bit more effort to get going. They also don’t have a built-in water circulation pump unlike the Webasto Thermo Top C heaters – they expect the water flow to be taken care of by the engine’s coolant pump.

Webasto Label
Webasto Label
Water Side
Water Side

The water ports are on the side of this heater instead of the end, the heat exhanger is on the left. These hearers are fitted to the car under the left front wing, behind a splash guard. Pretty easy to get to but they get exposed to all the road dirt, water & salt so corrosion is a little problem. The fuel dosing pump is in a much more difficult spot to get at – it’s under the car next to the fuel tank on the right hand side. Access to the underside with stands is required to get at this.

ECU Side
ECU Side

The ECU side has all the other connections – Combustion air, exhaust, fuel, power & control.

External Connectors
External Connectors

Only two of the external connectors are used on these heaters, the large two pin one is for main power – heavy cable required here as the current draw can climb to ~30A on startup while the glow plug fires. The 8-pin connector on the left is the control connector, where the CAN / K-Line / W-Bus buses live. The fuel dosing pump is also supplied from a pin on this connector. The small 3-pin under that is a blank for a circulation pump where fitted. Pinouts are here:

PinSignal
1Battery Positive
2Battery Negative
Pin NumberSignalNotes
1Telestart / Heater EnableWould usually start the heater with a simple +12v ON signal, but is disabled in these heaters.
2W-Bus / K-LineDiagnostic Serial Bus Or Webasto Type 1533 Programmer / Clock
3External Temp Sensor
4CAN-CAN Bus Low
5Fuel Dosing PumpFuel Pump output. Connect pump to this pin & ground. Polarity unimportant.
6Solenoid ValveFuel cutoff solenoid optionally fitted here.
7CAN+CAN Bus High
8Cabin Heater Fan ControlThis output switches on when heater reaches +50°C to control car heater blower
PinSignalNotes
1??
2Circulation Pump +
3Circulation Pump -
ECU Cover Removed
ECU Cover Removed

Removing the clipped-on plastic cover reveals the other ECU connectors. The large white one feeds the glow plug, & the large multi-pin below brings in the temp & overheat sensor signals.

MC9S12DT128B Microcontroller
MC9S12DT128B Microcontroller

The heart of the ECU is a massive microcontroller, a Freescale MC9S12DT128B, attached to a daughterboard hooked into the ECU power board.

Power Section
Power Section

The high power section is on the board just under the connectors, here all the large semiconductors live for switching the fan motor, glow plug, external loads, etc.

LIN & CAN Bus Transceivers
LIN & CAN Bus Transceivers

The bus transceivers are separate ICs on the control board, a TJA1041 takes care of the CAN bus. There’s also a TJA1020 LIN bus transceiver here, which is confusing since none of the Webasto documentation mentions LIN bus control.

Combustion Fan Motor
Combustion Fan Motor

The combustion fan motor is in the ECU compartment, nicely sealed away from the elements. There is no speed sensor on these blowers, unlike the Eberspacher ones.

Motor Details
Motor Details

The motor is a Buhler, rated at 10.5v.

Water Ports & Combustion Fan Cover
Water Ports & Combustion Fan Cover

Unclipping the cover from the other end reveals the combustion fan, it’s under the black cover. (These are side-channel blowers, to provide the relatively high static pressure required to run the burner).

Sensor Clip
Sensor Clip

The overheat & temperature sensors are on the end of the heat exchanger, retained by a stainless clip.

Temp & Overheat Sensors
Temp & Overheat Sensors

With the clip removed, the sensors can be seen better. There’s some pretty bad corrosion of the aluminium alloy on the end sensor, it’s seized in place.

Burner
Burner

The heater splits in half to reveal the evaporative burner itself. I’ve already cleaned the black crud off with a wire brush here, doesn’t look like this heater has seen much use as it’s pretty clean inside.

Burner Chamber
Burner Chamber

Inside the burner the fuel evaporates & is ignited. There is a brass mesh behind the backplate of the burner to assist with vaporisation.

Glow Plug
Glow Plug

The glow plug is fitted into the side of the burner ceramic here. This is probably a Silicon Carbide device. It also acts as a flame sensor when the heater has fired up. The fuel inlet line is to the left under the clamp.

Heat Exhanger
Heat Exhanger

The hot gases from the burner flow into the heat exchanger here, with many fins to increase the surface area. There’s only a couple of mm coating of carbon here, after 10 years on the car I would have expected it to be much more clogged.

I’m currently waiting on some components to build an interface so I can get the Webasto Thermo Test software to talk to the heater. Once this is done I can see if there are any faults logged that need sorting before I can get this heater running, but from the current state it seems to be pretty good visually. More to come once parts arrive!

The full service manual for these heaters can be grabbed from here, along with the wiring details for the Jaguar implementation & the Thermo Test software for talking to them:

[download id=”5618″]

[download id=”5620″]

[download id=”5622″]

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Honda GX35 Clone – Are They Any Good?

In a word, no they aren’t any good. As usual, cheap doesn’t equal good, and in this case the cheapo clones are a total waste of money. Read on for the details!

I’ve been looking into using a cheap Chinese clone Honda GX35 engine to drive an automotive alternator as a portable battery charging & power unit. These engines are available very cheaply on eBay, aimed at the mini-bike/go-kart market.
For those not in the know, the Honda GX25/35 4-strokes are strimmer-type engines that traditionally were always of 2-stroke construction. Honda worked out how to have a wet-sump engine without the need to keep the engine always in the “upright” position. They do not require mixing of oil into the fuel for lubrication as 2-strokes do, so should be much cleaner running.

So far I’ve had two of these cheap engines, as the first one died after only 4 hours run time, having entirely lost compression. At the time the engine was idling, no load, having been started from cold only a few minutes before. Having checked the valve clearances to make sure a valve wasn’t being held partially open, I deduced that the cause was broken piston rings. This engine was replaced by the seller, so I didn’t get a chance to pull it to bits to find out, but I decided to do a full teardown on the replacement to see where the cloners have cut corners.

Oil Return Hose
Oil Return Hose

I’ve already stripped off the ancillary components: exhaust, carburettor, fuel tank, cowlings, as these parts are standard to any strimmer engine. The large black hose here is the oil return feed back to the rocker cover from the crankcase. The oiling system in these engines is rather clever. The main engine block is made of light alloy, probably some permutation of Aluminium. There is much flashing left behind between the cylinder fins from the die-casting process, and not a single engine manufacturer’s logo anywhere. (From what I’ve read, the genuine Honda ones have their logo on the side of the crankcase).

Rocker Box
Rocker Box

Here’s the top of the engine with valves, rockers & camshaft. All the valve gear up here, minus the valves themselves & springs, are manufactured from sintered steel, there are no proper “bearings”, the steel shafts just run in the aluminium castings. The cam gear is of plastic, with the sintered steel cam pressed into place. The cam also has the bearing surface for the pin that the whole assembly rotates on. The timing belt runs in the oil & is supposed to last the life of the engine, and while I’d believe that in the original Honda, I certainly wouldn’t in this engine. The black grommet is the opening of the oil return gallery.

Cam
Cam

Here’s the cam on the back of the plastic pulley. A single cam is used for both intake & exhaust valves for space & simplicity.

Intake Valve Stem Seal
Intake Valve Stem Seal

Just visible under the intake valve spring is a simple stem seal, to hopefully prevent oil being sucked down the valve guide into the cylinder by intake vacuum. Running these cheap engines proves this seal to be ineffective, as they blow about as much blue oil smoke as a 2-stroke when they’re started cold. 😉

Starter Side
Starter Side

The starter side is where the oil sump is located on these engines, along with the dipstick.

Flywheel Side
Flywheel Side

The flywheel end of the engine is the usual fare for small engines. Ignition is provided by a magneto, with a magnet in the flywheel. This is no different from the 2-stroke versions. As these ignitions fire on every revolution of the crankshaft, the spark plug fires both on compression, igniting the fuel for normal operation, and again into the exhaust stroke, where the spark is wasted.
One thing I have noticed about these engines is an almost total lack of cooling air coming through the cowling over the cylinder cooling fins. Plenty was flowing over the exhaust silencer side, I believe bad housing design would be what causes this problem. A lack of cooling certainly wouldn’t help engine longevity!

Engine "Sump"
Engine “Sump”

Separating the bottom of the engine was a little difficult, as there is a significant bead of sealant used instead of a gasket. Inside the sump of the engine are a pair of paddles, which stir up the oil into a mist. As the piston moves in the cylinder, it acts as a pump, creating alternating pulses of pressure & vacuum in the crankcase. Oil mist flows through a drilling in the crank from the sump, into the crankcase where it (hopefully) lubricates the bearings & the cylinder wall. Incidentally, the only main bearings are on the crankcase – the far end of the shaft that carries the oil paddles & timing belt is just flapping in the breeze, the only support being the oil seal in the outer housing. The crank itself isn’t hardened – a file easily removes metal from all parts that I could get at. The big end journal pin might be, but these cranks are pressed together so I can’t access that part.

Lubrication Gallery
Lubrication Gallery

The oil mist feeds into the crankcase through this hollow section of shaft, there’s a drilling next to the timing belt pulley to connect the two spaces together.

Lower Crankcase
Lower Crankcase

The lower crankcase is just a simple die casting, there’s a check valve at the bottom under the crankshaft to transfer oil to the rocker cover, through the rubber tube on the outside of the engine. After the oil reaches the rocker box, it condenses & returns to the sump via the timing belt cavity.

Piston Crown
Piston Crown

Removing the crankshaft from the engine block gives me a look at the piston. The factory couldn’t even be arsed to machine the crown, it’s still got the rough finish from the hot-forging press. This bad finish will pick up much carbon from combustion, and would probably cause detonation once enough had accumulated to become incandescent in the heat of combustion. Only the centre is machined, just enough for them to stamp a number on.

Cylinder Bore
Cylinder Bore

A look up the cylinder bore shows the valves in the cylinder head. These engines, like their 2-stroke cousins have a single casting instead of a separate block & head, so getting at the valves is a little more of a pain. The cylinder bore itself is a cast-in iron liner and it’s totally smooth – like a mirror finish. There’s not a single sign of a crosshatch pattern from honing. If the first engine that died on me was the same – I’d be surprised if it wasn’t, this could easily cause ring breakage. The usual crosshatch pattern the cylinder hone produces holds oil, to better help lubricate the piston & rings. Without sufficient lubrication, the rings will overheat & expand far enough to close the end gap. Once this happens they will break.

Engine Valves
Engine Valves

Finally, here’s the valves with their springs removed from the cylinder. These are the smallest poppet valves I’ve ever seen, a British penny is provided for scale.

In all, these engines share many components with the older 2-stroke versions. The basic crankshaft & connecting rod setup is the same as I’ve seen in many old 2-strokes previous, the addition of the rather ingenious oiling system by Honda is what makes these tiny 4-strokes possible. I definitely won’t be trusting these very cheap copies in any of my projects, reliability is questionable at the least. The apparent lack of cooling air flow over the cylinder from the flywheel fan is concerning, along with the corner-cutting on the cylinder finishing process & piston crown, presumably to reduce factory costs.

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Sony Watchman FD-280 Composite Video Hack

Hacked
Hacked

As with the previous Sony Watchman hack, injecting a composite video signal into this one is just as easy. I desoldered both the VIF/SIF IC & the digital tuner control (the tuner controller was still injecting it’s indicator into the video circuitry with the IF IC disconnected).

Composite video is on pin 18 of the Video IF IC, with the audio on Pin 13.

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Sony Watchman FD-20 Composite Video Hack

VIF IC Pads
VIF IC Pads

Hacking the Sony FD-20 to accept a composite input is easy – the tuner receives the RF transmission, produces an IF, this is then fed into IC201, a Mitsubishi M51364P Video IF Processor. The VIF IC then separates out the composite video signal, which is output on Pin 13 (in photo above, left side, 3rd pin from the top). The audio is separated out & sent via Pin 11 to the Audio IF processor.

In the above photo, the VIF IC has been removed from the board with hot air, as it was interfering with the signal if left in place. The RF tuner was also desoldered & removed. Unfortunately I managed to mangle a pad, which is the ground pin for the VIF IC. This isn’t much of an issue though, as an identical signal ground is available, just to the left of the IC.

Audio Input
Audio Input

The audio can be tapped into in a similar way, the circled pad in the centre of the photo marked SIF is the place, this is the output of the Audio IF processor to the audio amplifier. The Audio IF processor didn’t interfere with the injected signal, so it was left in place.

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Sky+ HD Set Top Box

Sky Box
Sky Box

Time for another teardown! I managed to fish this Sky+ box out of a skip, but to protect the guilty, all serial numbers have been removed.
These are pretty smart devices, with DVR capability on board.

Ports 1
Ports 1

There’s a lot of ports on these units, from RS-232 serial, POTS modem, eSATA, HDMI, USB, Ethernet, SCART, Optical, digital outputs & even composite video.

Ports 2
Ports 2
Ports 3
Ports 3
Top Panel
Top Panel

Removing the top plastic cover reveals the operation buttons & the built in WiFi adaptor, which is USB connected to the main logic board.

Front Panel
Front Panel

The PCB on the front of the chassis has all the indicators, and the IR Receiver for the remote.

Cover Removed
Cover Removed

Removing the top shield of the chassis reveals the innards. The PSU is on the top right, 500GB SATA disk drive in the bottom centre. The main logic PCB is top centre.

Logic PCB
Logic PCB

Here’s the main logic PCB. The massive heatsink in the middle is cooling the main SoC, below.

SoC
SoC

The main SoC in this unit is a Broadcom BCM7335 HD PVR Satellite System-On-Chip. It’s surrounded by it’s boot flash, a Spansion GL512P10FFCR1 512Mbit NOR device. It’s also got some DRAM around the left edge.

Smart Card Reader
Smart Card Reader

The smart card reader is on the PSU PCB, the controller here is an NXP TDA8024

PSU PCB
PSU PCB

The PSU itself is a pretty standard SMPS, so I won’t go too far into that particular bit. The logic PCB attaches to the large pin header on the left of the PSU, some of the analogue video outputs are also on this board.
There’s also a Microchip PIC16F726 microcontroller on this PCB, next to the pin header. Judging by the PCB traces, this handles everything on the user control panel.

Power Supplies
Power Supplies

Some local supplies are provided on the logic board for the main SoC, the IC in the centre here is an Allegro A92 DC-DC converter. I didn’t manage to find a datasheet for this one.

LNB Front End
LNB Front End

The RF front end for the satellite input is a Broadcom BCM3445 Low Noise Amplifier & Splitter, again not much info on this one.

RS232 Section
RS232 Section

The standard MAX232 is used for the serial interface. I imagine this is for diagnostics.

Modem
Modem

The POTS modem section is handled by a Si2457 System-Side device & Si3018 Line-Side device pair.

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Quickie Teardown – ShopGuard Anti-Theft Tag

ShopGuard Anti-Theft Tag
ShopGuard Anti-Theft Tag

Everyone at some stage must have seen these EAS security tags in shops, usually attached to clothing with a steel pin. As some of this year’s presents had been left with the tags attached, I had to forcibly remove them before wrapping could commence.

Reverse Side
Reverse Side

These are just a plastic disc about 50mm in diameter, with an internal locking mechanism & RF tag inside.

RF Coil
RF Coil

After some careful attack with a saw around the glue seam, the tag comes apart into it’s halves. The RF coil & it’s ceramic capacitor can be seen wrapped around the outside of the tag. The capacitor in this case isn’t even epoxy dipped to save that extra 0.0001p on the manufacturing price. In the top centre is the pin locking mechanism, enclosed in a small plastic pill.

Lock Pill
Lock Pill

Popping off the back cap of the lock shows it’s internals.

Ball Bearing Lock Assembly
Ball Bearing Lock Assembly

The lock itself is very simple. The centre section, held in place by a spring, carries 3 small ball bearings. The outer metal frame of the lock is conical in shape.

When the pin is pushed into the tag, the conical shape of the lock chamber causes the ball bearings to grab onto it, helped by the action of the spring that pushes the ball bearing carrier further into the cone.
This also means that any attempt to force the mechanism causes it to lock tighter onto the pin.
In normal operation, removal is achieved by a strong magnet that pulls the ball bearing carrier back slightly against it’s spring, allowing the pin to disengage & be pulled out.

This design is incredibly simple & cheap to make, and gains it’s locking strength from friction alone.

I would consider the RF coil being around the outer edge of the device a bit of a security risk – a quick chop with a sharp pair of wire cutters would disable the tag’s alarm functionality instantly. Making the coil slightly smaller & keeping it out of reach of the edge of the tag would help in this regard.

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Rigol 12v Power Supply Project Wiring Loom

As the crimp tool for the PSU connector in the Rigol scope is a very expensive piece of hardware, I decided to use pre-crimped terminals, from an ATX power connector. (They’re the same type).

Wiring Loom
Wiring Loom

Here’s the partially completed loom, with the 13 cores for the power rails. The 14th pin is left out as that is for AC triggering, and this won’t be usable on a low voltage supply.
A couple of the pins have two wires, this is for voltage sensing at the connector to compensate for any voltage drop across the cable. The regulators I am using have provision for this feature.

Sleeving
Sleeving

To keep the wiring tidy, I dug a piece of braided loom sleeving out of the parts bin, this will be finished off with the heatshrink once the pins are inserted into the connector shell.
The remaining parts for the loom have been ordered from Farnell & I expect delivery tomorrow.

More to come then!

73s for now 🙂

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nbTanya Louise – New TV Antenna

Here’s the final instalment of the new high gain TV antenna & it’s masthead amplifier.

High Gain Antenna
High Gain Antenna

Here’s the new antenna on it’s removable mast. This apparently will give 13db of gain over the old antenna. The masthead amplifier box is mounted just below.

Amplifier
Amplifier

Here’s the amplifier just below the antenna. I do hope the seals on this hold against the weather! The amplifier inside isn’t protected at all.

Amplifier Module
Amplifier Module

Here’s the module itself. This is powered by +12v injected into the coax with the power supply I previously modified. F-type connectors are used. (I don’t like these connector types, their lack of a true centre pin is poor design in my opinion).

Here’s the power supply, mounted behind the TV where the cable comes through the hull.

PSU
PSU
Amplifier PCB
Amplifier PCB

Here’s the inside of the amplifier module. It’s very simple, with some input filtering to block out 4G mobile signals, and a single amplifier transistor.

 

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Solderless N-Type Connector Fitting

I thought I’d detail the process I use to fit an N-Type connector to a coax cable, as I don’t usually solder these connectors.

Backnut & Seal
Backnut & Seal

Before stripping, fit the backnut, washer & rubber seal onto the cable.

Stripped Coax
Stripped Coax

The cable is first stripped back to reveal the shield. This cable has a foil tape as well as the usual copper braid.

Shield Connection
Shield Connection

Once the inner core has been revealed, the shield washer is fitted. This has a knife edge on the inner diameter, to fit between the outer sheath & the shield, this makes the electrical connection.

Inner Insulation
Inner Insulation

With the shield washer fitted, the inner insulation can be cut back, it should be just about level with the final washer when you’re done, this allows the connector to fit together properly.

Center Core Trimmed
Center Core Trimmed

Trim the center conductor to about double the length required, to allow it to be folded over, as shown. This allows the copper to spring back against the center pin of the connector when it’s fitted, to allow a good connection.

Final Washer
Final Washer

Here the final washer is fitted over the shield washer. The center insulation should be at the same level to allow the center pin to fit properly.

Center Terminal
Center Terminal

Finally, the center pin is pushed over the inner conductor of the cable, with it’s insulating spacer. Soldering these usually results in the plastic melting and a ruined connector.

Finished Plug
Finished Plug

Finished plug. Make sure the backnut is tightened fully home, without twisting the connector body itself. After I’m done with the termination, I use self-amalgamating tape to form a strain relief on the cable. This prevents it from breaking at the point where it enters the backnut.

I’ve been terminating these connectors this way for a long time & have not had any issues with SWR or bad connections, dispite the fact that I don’t solder them. This also has the advantage that fewer tools are required for the job & the connectors can easily be reused should the cable wear out.

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Wouxun KG-UV950P Teardown & Analysis

Following on from my review, here are some internal views & detail on the components used in this radio. Below is an overview of the main PCB with the top plate removed from the radio.

Cover Removed
Cover Removed
RF Final Amplifier Stage
RF Final Amplifier Stage

Most visible are these MOSFETs, which are Mitsubishi RD70HVF1 VHF/UHF power devices.  Rated for a maximum of 75W output power at 12.5v (absolute maximum of 150W, these are used well within their power ratings. They are joined to the PCB with heavy soldering, with bypass caps tacked right on to the leads.

RF Pre Drivers
RF Pre Drivers

Here is the RF pre-driver stage, with intermediate transistors hidden under the small brass heatspreader.

Power Section
Power Section

In the top left corner of the radio, near the power input leads, is the power supply & audio amplifier section. Clearly visible are the pair of LA4425A 5W audio power amplifier ICs, these drive the speakers on the top of the radio. Either side of these parts are a 7809 & a 7805 – both linear regulators providing +9v & +5v logic supplies respectively. The large TO220 package device is a KIA378R08PI 3A LDO regulator with ON/OFF control, this one outputs +8v. Just visible in the top right corner are the sockets for the speaker connections.

DTMF Circuits
DTMF Circuits

Here are the two ICs for dealing with DTMF tones, they are HM9170 receivers.

Glue Logic
Glue Logic

In the corner next to the interface jack, there are some CD4066B Quad Bilateral switches. These make sense since the interface jack has more than a single purpose, these will switch signals depending on what is connected.

RF Section
RF Section

Here are visible the RF cans for the oscillators, the crystals visible next to the can at the top. The shields are soldered on, so no opening these unfortunately.
Also visible in this image is a CMX138A Audio Scrambler & Sub-Audio Signalling processor. This IC deals with the Voice Inversion Scrambling feature of the radio, & processes the incoming audio before being sent to the modulator.

Output Filter Network
Output Filter Network

Shown here is the RF output filter network, this radio uses relays for switching instead of PIN diodes, I imagine for cost reasons. The relay closest to the RF output socket has had a slight accident 🙂 This is slated to be replaced soon.

RF Output Jack
RF Output Jack

Finally, the RF output jack.

Audio Speakers
Audio Speakers

Here the speakers are shown, attached to the bottom of the top plate. They are both rated 8Ω 1W.

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Another Viewfinder CRT

Here’s another viewfinder CRT, removed from a 1980’s vintage VHS camera I managed to get cheap from eBay.

This unit is very similar to the last one I posted about, although there are a few small differences in the control circuitry.

Viewfinder Schematic
Viewfinder Schematic – Click to Embiggen

Here’s the schematic, showing all the functional blocks of the viewfinder circuitry. An integrated viewfinder IC is used, which generates all the required scan waveforms for the CRT.
On the left is the input connector, with the power & video signals. Only pins 2 (GND), 3 (Composite video), & 4 (+8v) are needed here. Pin 1 outputs a horizontal sync signal for use elsewhere in the camera, while pin 5 fed the recording indicator LED.

To make connection easier,  I have rearranged the wires in the input connector to a more understandable colour scheme:

Input Connector
Input Connector

Red & Blue for power input, & a coax for the video. For the video GND connection, I have repurposed the Rec. LED input pin, putting a shorting link across where the LED would go to create a link to signal ground. Keeping this separate from the power GND connection reduces noise on the CRT.

Viewfinder CRT Assembly
Viewfinder CRT Assembly

Here’s the complete assembly liberated from it’s plastic enclosure.

PCB Closeup
PCB Closeup

Closeup of the control PCB. The 3 potentiometers control the CRT brightness, focus & vertical size.

M01KGG007WB CRT
M01KGG007WB CRT

The tiny CRT. Only ~60mm in length, with an 18mm screen size. This tube runs on +2294v final anode voltage. Much higher than I expected.

Electron Gun Closeup
Electron Gun Closeup

The electron gun assembly, with the cathode, focus & final anode cups.

Phosphor Screen
Phosphor Screen

This screen is just a little bigger than a UK 5p piece! A marvel of precision engineering.

 

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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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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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445nm Laser TTL Interface

TTL Interface
TTL Interface

In preparation for my laser scanner project, I have modified my existing 445nm laser to accept a TTL blanking input. The laser driver is already enabled for this & just required an extra connection to interface with my laser scanner showboard. I have used an 8-pin connection to allow the same cable & interface to be used with an RGB laser system, when it arrives. The signals are as follows, from top centre, anti-clockwise:

Pin 1: +12v Power
Pin 2: Blue TTL
Pin3: GND
Pin 4: Green TTL
Pin 5: GND
Pin 6: Red TTL
Pin 7: GND
Centre: Power GND

 

Custom TTL Cable
Custom TTL Cable

Here is the custom 8 core cable, which connects to the laser scanner show board. This cable allows the laser to be used for projection while still retaining the portable function & the keylock arming switch. When plugged in the cable bypasses the keyswitch & provides 12v DC direct to the laser driver.

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USB-IDE/SATA Adaptor

Front
Front

This is a device to use an IDE or SATA interface drive via a USB connection. Here is the front of the device, IDE interface at the bottom, 2.5″ form factor.

PCB Top
PCB Top

PCB removed from the casing. USB cable exits the top, 12v DC power jack to the left.
SATA interface below the DC Jack.
Molex connector below SATA is the power output for the drive in use. This unit has a built in 5v regulator.

PCB Bottom
PCB Bottom

Bottom of the PCB showing the interface IC.

Drive Adaptor
Drive Adaptor

Adaptor to plug into the 44-pin 2.5″ form factor IDE interface on the adaptor, converts to standard 40-pin 3.5″ IDE.

Power Cable
Power Cable

Power pigtail with standard Molex & SATA power plugs.

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Laser Diode Driver

Connection

Closeup
Closeup

The parts arrived for my adjustable laser diode driver! Components here are an LM317K with heatsink, 100Ω 10-turn precision potentiometer, 15-turn counting dial & a 7-pin matching plug & socket.

Driver Schematic
Driver Schematic

Here is the schematic for the driver circuit. I have used a 7-pin socket for provisions for active cooling of bigger laser diodes. R1 sets the maximum current to the laser diode, while R2 is the power adjustment. This is all fed from the main 12v Ni-Cd pack built into the PSU. The LM317 is set up as a constant current source in this circuit.

Installed
Installed

Here the power adjust dial & the laser head connector have been installed in the front panel. Power is switched to the driver with the toggle switch to the right of the connector.

Regulator
Regulator

The LM317 installed on the rear panel of the PSU with it’s heatsink.

Connection
Connection

Connections to the regulator, the output is fully isolated from the heatsink & rear panel.

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Epson Ink Cartridge Resetter

Interface
Interface

This is a device designed to reset Epson brand ink cartridges that are reportedly out of ink, so they again report full to the printer Here is the front of the unit, with the guide for attaching to a cartridge.

PCB Back
PCB Back

Back of the device removed. 3 button cells provide power to the PCB. Indicator LED sticks out of the top of the device for reset confirmation.
Row of pads on far left edge of the PCB are presumably a programming header for the uC on the other side of the board.

PCB Front
PCB Front

Here is the  front of the PCB, main feature being the grid of pogo pins to connect to the cartridge chip. IC on lower right of that is a MSP430F2131 uController, a Texas Instruments part.
The IC directly to the left of the pogo pin bed is a voltage regulator, to step down the ~4.5v of the batteries down to the ~3.3v that the uC requires.