Trying to figure out a simple Integrated Circuit...

Need help with a project? Trying to find a component? Post any general technical questions here.
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Kai
Posts: 3
Joined: Thu Oct 09, 2008 11:44 pm

Trying to figure out a simple Integrated Circuit...

Post by Kai » Thu Oct 09, 2008 11:59 pm

Okay, so, it's my first post - hi :)

Now, down to business!

Basically, i'm trying to repair a bulb-failure module in my Toyota - now the module was discontinued by Toyota in 1998 and there are none left anywhere in any stockroom on planet earth, according to them, plus the module was £98. Having looked at the inside of this thing, it's hard to see why they charged so much, other than 'because they can'. Most of the module is composed of standard parts, bar two integrated circuits.

I've found that there are numerous part numbers from different manufacturers, but they all have the same design and function.

Fujitsu call it the MB4210
KEC/Samsung call it the KIA4210SV
Toshiba call it the TC17G005AP-0012

I find its nearly impossible to find these parts from anywhere, although so many dodgy looking IC search engines have said 'sure, we have loads of them', and i've fired off a request/quote, but i'm not overly hopeful.

However, two of the datasheets i've downloaded for the Fujitsu and the KEC parts both give a block diagram of how the IC works internally, so i was thinking about making a circuit that does the same job as the IC if i can't get hold of the original parts.

See the datasheet here: http://keccorp.ru/data/cat_datasheets/KIA4210SV.pdf

Now, theres a Comparator in there, and what looks to be a 3 way OR gate, but because of the 'engrish' transration (ho ho ho), the other functions are somewhat vague and no amount of searching seems to bring up a result.

Could anyone on here possibly point me in the direction of either a) where to buy an obsolete IC (preferably in a the thousands, should i balls up, and for other owners who are at a dead end with finding the module) or b) how to figure out what components are needed to complete the circuit in understandable terms so that i can knock up a PCB that does the same job.

Cheers and TIA! :)

Martingrove
Posts: 15
Joined: Tue Aug 26, 2008 1:13 am

Re: Trying to figure out a simple Integrated Circuit...

Post by Martingrove » Fri Oct 10, 2008 4:30 pm

Hai Kai,
Have you tried a Toyota breaker's yard?
Martin

Kai
Posts: 3
Joined: Thu Oct 09, 2008 11:44 pm

Re: Trying to figure out a simple Integrated Circuit...

Post by Kai » Fri Oct 10, 2008 6:10 pm

Martingrove wrote:Hai Kai,
Have you tried a Toyota breaker's yard?
Martin
None there. Mk3 Supra's are hard to find in the UK, even when they were all running. The 2nd hand supply is drying up worldwide.

Martingrove
Posts: 15
Joined: Tue Aug 26, 2008 1:13 am

Re: Trying to figure out a simple Integrated Circuit...

Post by Martingrove » Sat Oct 11, 2008 12:56 pm

Well, the IC seems pretty uncomplicated except for the "memory" bit. I can't make out what it's supposed to do unless it records a voltage level with the brake lights on. But even that does't make sense since the voltage would fall when they come on and the comparator should only respond to a rise in voltage.
Reconstructing the IC seems like a lot of effort, though. There must be many other models besides Toyota that used that chip.
Martin

Kai
Posts: 3
Joined: Thu Oct 09, 2008 11:44 pm

Re: Trying to figure out a simple Integrated Circuit...

Post by Kai » Sun Oct 12, 2008 12:28 am

Seems to have been a fairly industry standard IC years ago, but now everything is microcontroller based, making it more expensive for us to fiddle with it. The parts have all been discontinued by all the quoted manufacturers for at least the last 10 years :(

On another forum, someone gave me this explanation:

Pins 1,2,3, constitute a current sense circuit the external potentiometer in the application circuit (R3) lets you adjust the current sense threshold. If the current sense on between pin 1,2 to 3 drops below threshold, the comparator activates and sends a positive signal to the 3 input OR gate.

Pin 4 is the memory circuit. It is connected to an external capacitor that charges if the comparator is activated. It's basically a "lock-on" for the comparator. If the lamp is jittering, usually an indication of impending failure. The delay locks on the indicator light to make sure you see that.

Pin 8 is the blow fuse detection circuit. A voltage is measured between it and ground. If it drops to ground then that means the fuse is blown. It then sends a positive signal to the OR Gate.

Pin 6 is the power output driver that sinks current if the OR-gate is activated.

Martingrove
Posts: 15
Joined: Tue Aug 26, 2008 1:13 am

Re: Trying to figure out a simple Integrated Circuit...

Post by Martingrove » Fri Oct 17, 2008 1:03 pm

Deleted
Last edited by Martingrove on Mon Oct 20, 2008 7:29 am, edited 2 times in total.

Biffo
Posts: 72
Joined: Sun Mar 09, 2008 3:24 pm

Re: Trying to figure out a simple Integrated Circuit...

Post by Biffo » Fri Oct 17, 2008 1:36 pm

What about using a bulb failure circuit from a more popular car in the scrap yard?

up market Ford Sierras and Mondeos had bulb failure indicators , so maybe the main problem then would be trying to interface it with your dash display?

Then again you might get lucky and find the same circuit and chip in there?

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