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Old 04-04-2002, 02:24 PM
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Join Date: Nov 2000
Location: Umeň,Sweden
Posts: 46
Killed my KE-Jetronic -300E bosch Trap ?

Bosch number 0280800286
Inside the box is 2 main PCB:s - circuit boards.
1 pcb for the logic cpu,rom.
1 pcb for the powercomponents which the main connector is soldered to.
My goal was to check the soldering in the the box.
The logic pcb was properly soldered but the "power" pcb had about 4 bad soldering joints.
There is also a 3rd pcb ,its a small one with a black plastic cover located standing in the middle of the "power" pcb.
Don┤t ever try to remove the small plastic cover,like i did.
Inside there is a small chip which is glued with a little plastic ring around the chip.The chip is connected with microscopic thin leads
which is "in the glue"
When you take of the plastic you move the plastic ring which cuts off the chip leads.
Could this be a copy protection thing ?

Other info for the electronics interested.
Intel/philips 8836v3 cpu + rom
+5 volt 5-pin voltage regulator.
An interinsting thing is the push/pull configuration for controlling the EHA.
The EHA is current limited with 20 Ohm.(2pcs 40 ohm in parallell)
When i get my new box,i will connect 2 leads to the resistor(s) This will make it easier to measure EHA current.
10mA will be 0,2 Volts.

The OVP power to the Jetronic is easily checked by removing the black cover on the Big connector and check 12volts on pin number 1 when the car is turned on.

With modern electronics you could have this function in almost molded in the cable.


300E 4M 5speed -89
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Old 04-04-2002, 02:55 PM
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Join Date: Jun 2000
Location: Saugus, CA USA
Posts: 2,007
The number you gave for the intel cpu I think is the date code. Are there any other numbers on it?
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Old 04-04-2002, 03:22 PM
dpetryk's Avatar
Electrons can do anything
Join Date: Sep 2001
Location: Houston, Texas
Posts: 1,071
What you are describing is a technology called "Chip on Board". It is where a silicon chip in its raw form is glued to the PCB. The chip is then "bonded out" with very small wires to the PCB traces on the board. It is a very low cost method of implementing integrated circuit to PCB assemblys. It is used in very high volume applications where they want to keep the cost down. Nowadays they use an epoxy blob to cover the chip and the bond out wires.

It is not a copy protection thing and it is very delicate.
I got too many cars!! Insurance eats me alive. Dave

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Old 04-09-2002, 04:46 PM
Registered User
Join Date: Nov 2000
Location: Umeň,Sweden
Posts: 46
The main cpu:

all numbers

B 57 512
DSD8836V3 C
INTEL 1980

The Eprom:

S56020 <- Standard intel eprom

There is a label put over the "eraser hole" with numbers
2 287 356 511

I/O chip ?:

Texas Instruments


+2 pcs Ti B57356 (8835ar)
+1 pcs SN74LS02NAM
+1 pcs 7-pin "very strange" 30004 4088 <-looks like a bosch mark on it.

About the "glued" chip :
When you try to remove the black cover then you may destroy the chip ,because there is a notch on the cover which takes the little plastic ring away that is assembeled right over the "glued"chip.
This plastic ring could also be a protective thing for the glued chip.
I dont like that "notch"
My idea of copy protection is:
Since the 3:rd "glue chip" pcb is located on the power board it could be some kind of checksum thing for the rom.
This would prevent people from repairing the control unit by taking a power board from a similar car/KE-Jetronic.
Like a key ,if the cpu/rom cant find a key on the powerboard it wouldnt start. <-a wild guess.
The 3:rd pcb is wired directly from the powerboard to the cpu itself.

I have installed a new (used) box,and it seems to be working properly.

Maybe i will copy (backup) the eprom from the old box and have a look at it.

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