Hi all - we all know that A/T governor computers CAN be a pain, and the improvements are well documented, but does anybody have a circuit diagram for the governor computer at all? Does one even still exist?
I fear I may have cooked mine with some over-enthusiastic solenoid testing!
Hi Richard,
It's months ago sonce you asked this question and I have not seen a reply since.
Did you yet find the requested diagram?
If not, say so, I may be of help.
Welmoed.
Vita contig git. Vive com eo.
Well i would love to see one that the club can use, i keep asking around for this info too but to no avail
Ed Uding offers a AT 'computer 'service, but i figure you want to have a go at it yourself ?
hi there
ask no more my new one comes tomorrow and there shuld be a new paperwork with it so i will lwt you know
I found a diagram that still is in it's original form: a drawing by an American D driver's uncle. That guy seems to be learned.
I have the intention to recreate the drawing into an electronical version.
At the same time I will compose the parts list I got from a German owner and add that to the documentation, with some pictures. As soon as I have that ready I will send it to you (in person or through this forum? Just tell me).
There is still some info I need: this concerns the "generator" that supplies the power for the circuit of the governor computer. The three connections from the generator to the board are yet somewhat foggy to me. Woukld like to know which funcions they have (GND, etc). Anyone familiar with that part?
My D happens to love the first gear when it's started, however the test circuit shows an almost immediate drain and when rolling the car out it's in second instead of first. Second and third operate normally and kickdown also functions.
The computer has been revised as for the defective C's. Next step is to replace the power transistors and perhaps the comparators and the remaining transistors just for making sure the major parts are okay.
Well, no one ever said life would be easy. That applies to car lovers too.
I have rebuilt a few at this stage with 100% success (thank god).
If anyone needs the caps and transistors for rebuilding them let me know I have enough to rebuild ten computers.
Thanks for the offer, Paul.
As for the power transistors (42C), those are already purchased.
I have BC237B and capacitors. The only part(s) missing are the comparators TCA135A. These seem obsolete.
Do you have found replacements for these ICs?
Besides that, I would like to get some info on the signals coming from the generator and other signals on the 3 pins (to the circuitry) in the case of the computer.
Should you have that info, please tell me what these pins connect to, so I do not have to delevop the wheel again.
Thanks,
Welmoed.
VIN 2572
This would be a nice club tech write-up !
NickT.
The three signal pins are
Output A - Ground - Ouput B
The generator creates an AC voltage between 0 - 30(odd) volts.
Output A is 180 dgrees out of phase with Output B and runs at around 50Hz when the gear changes are happening - though the frequency varies with speed.
There are two 20v zener diodes in series with the generator output to clip it at 20v on the PCB.
The TCA315A is obsolete, and as far as i can tell does not have a replacement. It's very unlikely they have gone faulty. If your D is jumping into second too early, check the throttle position feedback cable is not loose, as this will affect the change points. Apart from the caps these circuits are terrible for dry joints, which can be hard to spot under the varnish, the interconnecting ribbon is particularly bad for them.
I have now built a simple test rig for the governor computer assembly, so I can check them out properly....
Hi Welmoed, Richard.
I have not got the TCA135A chips but am currently researching other comparator chips and checking their data sheets to see if I can find one that is a cross reference. Its a very slow process
I will keep you posted :wink:
Ups,
That was meant to be TCA315A
Keep up the good work !
I've got a friend that could re-make the circuit boards if need be!
It would be useful if the club had a spare computer re-build and ready to go.
NickT.
Thats what it is all about buddy,
We all help each other.
Be nice to have a new unit rather than a refurbished one, but it seems to be the same 'problem' in the US getting a new one on the market ....
Like any part on our vehicles the original computer is very good once the right upgrades have been done and the vehicle is charging and running right and has a good battery.
A bad battery or jump starting even kills modern vehicles.