Need help finding a schematic

[The Mad Electrician]

Ok, I have a retractor control module for my MR2 that needs trouble shooting/Rebuilding

I do have a spare I pulled from a parts car (also bad) so If I screw one up learning it's not as big of a deal

Here is my initial question
Is it possible to track down a schematic for trouble shooting?

If yes here is my next question
What information from the part do you need to assist me in finding a schematic?

I have already contacted Denso, and Toyota and neither of them are willing to give or sell me a schematic. Toyota wants to sell me a $160 replacement. But seeing as how I have a DIY attitude, limited budget, and am cheap. Id rather do it my self.

On that note I have also scoured the board and can find no obvious signs of damage.

I have also spent much time on Google and yahoo looking but to no avail. I am hoping someone here may have resources that I do not or just know a trick that I don't.

Than you in advance.
Pic of the part and all of the markings on the outside
**broken link removed**

Thank you in advance for any help.

 

[mvs sarma]

By nature nothing is impossible. The whole unit is moulded in epoxy or some compound for their own reasons. But natural they wold not part with design info. melting the epoxy is a costly affair. if it is a general discrete design, you can reverse engineer and generate a schematic, no doubt, But if it micro-controller based and if software is code protected(which they will do), you may not gain much info. Then you should be able to write software.
in case of discrete even , if the components are coded and don't contain general names, you will again be left to imagination.

I feel, better buy a piece for$160 be done with it. you want to do independent design, after studying what exactly is the need of the location or case . you can always.

BTW, I saw "retractor control module" by google search and these are available MR2 version for less than $20/- why not give it a try
see this site
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[Hero999]

What exactly is a retractor control?

It might actually be a fairly simple thing to make.

 

[ParkingLotLust]

The retractor control controls the headlight retraction.

Nice car, by the way

 

[The Mad Electrician]

It is not cast in epoxy, actually the only thing covering it is the plastic case. I will take a pic of the inside tommorrow and post it.

 

[mvs sarma]

It is not cast in epoxy, actually the only thing covering it is the plastic case. I will take a pic of the inside tommorrow and post it.

try to post photos of both component and solder sides with close up view. awaiting to see them.

 

[Papabravo]

Using my X-ray vision on the picture you provided I see a little black blob on the PC board. This is proabably an unpackaged custom circuit attached to the PC board and protected from the environment with the black blob. In this case you have virtually no chance of deconstructing the innards.

 

[The Mad Electrician]

Using my X-ray vision on the picture you provided I see a little black blob on the PC board. This is proabably an unpackaged custom circuit attached to the PC board and protected from the environment with the black blob. In this case you have virtually no chance of deconstructing the innards.

Good thing for me you have shoddy X-Ray vision j/k

**broken link removed**
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[jumides]

Additional info.

 

[mvs sarma]

Nice photos Mad Electrician. I feel, by these photos you really helped yourself. rest of the work is simple.

View attachment 16415

Additional info.

Sure that you are going to post the circuit even, like you the overlapped photo with components on the solder side. Really Nice.

 

[justDIY]

doesn't look so bad - all through hole components, and most of them are passive

what does it do or not do that is wrong?

maybe the relay contacts are corroded, or one of the transistors has wigged out

 

[Hero999]

If you can find the datasheets all the semiconductors (or at least the transistors) on the Internet then reverse engineering it should be easy.

Another thing is, are you sure it's gone wrong? Have you checkd for bad connections elsewhere and are sure that it's not the motors on the headlights or anything like that.

 

[mvs sarma]

If you can find the datasheets all the semiconductors (or at least the transistors) on the Internet then reverse engineering it should be easy.

Another thing is, are you sure it's gone wrong? Have you checkd for bad connections elsewhere and are sure that it's not the motors on the headlights or anything like that.

i have given tentative component numbers and perhaps The Mad Electrician can try to check and create a component list and post it. for that purpose i created a notepad list for him to fill up. both are attached.

However i expect some regulator chips like 78Lxx

 

[The Mad Electrician]

If you can find the datasheets all the semiconductors (or at least the transistors) on the Internet then reverse engineering it should be easy.

Another thing is, are you sure it's gone wrong? Have you checkd for bad connections elsewhere and are sure that it's not the motors on the headlights or anything like that.

Thats where I first began to look, here are the steps I took to diagnose and end up where I am at now.

Apply 12 volts to motors.
Pass

Verify that 12V is being transfered from RCM (RCM absent) Connection to Motors
Pass

Verify that Signal 12V is being transfered from switch in car to RCM Connection
Pass

Verify that 12V is going from RCM to motors
FAIL

I will admit that this is approaching the limits of my electrical knowledge, but I joined this forum so that I could learn from the experience and knowledge of others, and expand my own knowledge. I have always been fascinated by circuitry and how things work. I wanted to take a basic circuitry class but the college I attend doesn't offer it or any thing near it. So now for the stupid questions.

i have given tentative component numbers and perhaps The Mad Electrician can try to check and create a component list and post it. for that purpose i created a notepad list for him to fill up. both are attached.

How do I go about doing this? How do i identify (what they are) the individual components. I know the basics, resistor, capacitor, diode, etc. How do I break it down further than that?


By the way the only thing I have yet to do as far as testing goes is to finger the relays and see if they are still good. But there is no visible corrosion.

Thanks to everyone for helping me, and thanks in advance for putting up with my stupid questions.

 

[Hero999]

Semiconductors, i.e. transistors, diodes and ICs have part numbers on which you can normally type into Google and get the datasheet. Most pin outs aren't except for diodes, normally have a band on one end that denotes the cathode.

http://www.madlab.org/electrnx/electrnx.html
http://www.uchobby.com/index.php/2007/07/15/identifying-electronic-components/

Ceramic capcitors are always marked in picofarads which the last digit being the number of zeros, if there's a p, a black mark on the top, it's underlined or the number contains a decimal, it normally means there are no zeros.

For exanple 104 means 100,000pF, 100nF or 0.1:mu:F, 2p2 and means 2.2pf, 4.7 means 4.7pf.



If you know all the pin outs, all the component values and how they're connected together then drawing a schematic is easy.

 

[tytower]

I'll lay odds if you force the relays to work the trouble will be the contact points -give them a clean and away they will go -

Bets anyone?

 

[The Mad Electrician]

i have given tentative component numbers and perhaps The Mad Electrician can try to check and create a component list and post it. for that purpose i created a notepad list for him to fill up. both are attached.

However i expect some regulator chips like 78Lxx

Done


See Zip for excel spread sheet If you do modify my sheets please update the version i.e. 1.0 to 1.1

Also on my resistor math if I have the formula correct please change the Verified column from No to Yes Hopefully I got this right

Now how do I do a search for the transistors/ semiconductors?

 

[mvs sarma]

Done


See Zip for excel spread sheet If you do modify my sheets please update the version i.e. 1.0 to 1.1

Also on my resistor math if I have the formula correct please change the Verified column from No to Yes Hopefully I got this right

Now how do I do a search for the transistors/ semiconductors?

thanks, Let me do the rest wwof the work . I shall come back

 

[jumides]

thanks, Let me do the rest wwof the work . I shall come back

hi The Mad Electrician.
mvs sarma will do the rest!!, and you do the test!!.

edit:

 

[mvs sarma]

hi The Mad Electrician.
mvs sarma will do the rest!!, and you do the test!!.

**broken link removed**

Hai Jumides, You were already half way and I only tried to continue after inspiration from your marking.
BTW,
what was that attachment- unable to download?