Quite some time ago, I stumbled across a web site of some guys calling themselves the American Society of Reverse Engineering. Unfortunately they seem to have gone away. So, this page chronicles the things that I have reverse engineered, sometimes for fun, sometimes to fix it, and sometimes to redesign it so that it would actually work.
I found a source for brand new BP-7 and BP-8 batteries at a good price. But... the one I received didn't work right. So of course, out came the screwdriver...
The battery pack contains a small relay that reconfigures the cells as two banks of 6 cells to charge them. With the charger disconnected the configuration is one bank of 11 cells. So what happens to the missing cell? Well, one cell is shared by both banks. Why? well, an additional cell would have brought the voltage up to 14.4V and the IC2 was designed for < 13.8V. I would have used two banks of 5 cells each, for 12.0V, but the BP-7 was designed for maximum performance, thence this trick.
I found that the relay centre contact pin was broken, fortunately this type of relay has two pins connected together and I just soldered a wire from the other pin.
I also found that the "C" contact on the top of the battery case was shorting to the positive voltage when the battery is on the radio, so I rewired things so that the "C" contact is connected to the positive output.
I bought the service manual from Dmitri at www.electronicsrepair.net -- best $10 I've spent in a while. The service manual contains the complete schematic diagram and parts list.
Nifty things I have learnt:
I bought this card from Cape Ads for R350. This included the CDROM with the DVD player application, but not the disk with the driver. Drivers are available from creative though.
Eric Smith has hardware information on this card.
As far as I can seem you need the following stuff to make the card work (with Creative Labs Encore 12x PC-DVD drive)
This regulator comes off a small Bosch alternator from a 1600 VW Fox (Golf / Rabbit).
The watercooled VWs (Golf / Fox / etc) use a "TCI" ignition control module, with
a Hall Effect sensor in the distributor body, and a conventional-looking ignition
I received an email from Carlo W, who had managed to make this module work with conventional points on his V8 Land Rover, so I decided to investigate (I have a complete distributor / coil / TCI / loom lying around from a 1600 Fox we stripped).
I broke the top off the TCI module and partially traced the schematic (it's a thick film hybrid module covered in a transparent sticky gel [429k picture]). It basically consists of what looks like a zener based voltage regulator for the Hall Effect sensor, a chip which does all the clever stuff, and a driver transistor for the coil. So yes, feeding a pulse similar to that coming from the Hall Effect sender into pin 6 will work.
Now the question : Is the signal from a standard set of mechanical points close enough to that from the Hall Effect sensor? Carlo W said that his setup was giving too high a voltage (he claims a 5cm (that's 2&) spark), leading to arcing all over the place. He suspects this is because of the dwell time of the mechanical points.
Question-du-jour : does the Hall Effect sender pulse duration vary with engine speed, like points, or is it a fixed-time pulse? If fixed-time, one should be able to build something with a 555 to make everything happy.
This is the same unit as the GT-730F(L), but presumably with different firmware (The Venus chip contains on-chip FLASH program memory that can be user programmed. The serial FLASH is for data logging).
|Serial to USB bridge||PL-2303Hx|
|16Mbit CMOS serial FLASH||MX25L1605DM2I|
|GPS Chipset: Baseband Processor||Skytraq Venus 621dLP|
|GPS Chipset: GPS Receiver||SiGe 4150L|
Go to Control Panel / System (icon) / Hardware (tab) / Device Manager (button) / Ports and find the "Prolific USB-to-Serial Comm Port". Point your terminal program (I use Hercules) at this comm port at 115200 bps. You'll see the NMEA datastream from the unit.
There's obviously a control interface but that's a reverse-engineering job for another day.
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