924Board.org

McGyver · Posted: Sat Feb 20, 2010 9:25 pm Post subject:

I take out all resistors from PCB and check it with multimeter and confirm by barcode, so that all have to be correct. Most of them are in 5% tolerance group but not all, I add it later.
I correct that capacitors values which was listed before.

The most trouble thing is one diode:
V10 diode?? - 457TK (or TD 6|8 ITT)
I'm not sure what is it... propably some shottky but I can't find any accurate datasheet for that.

Another interesting thing is I think relase number on PCB:
US:05.21.01 c
ROW:05.21.01 d

And we have this "d" near track cutted in US version (7-th leg from MC14001BC). We can see that on pics before posted by Gegge and me.

Ideola - if you can please send me few good photos from your German unit - I add it to colection so maybe I found something more.

The best would be photos from 937 unit if someone have any??

I started this project becouse I don't want to change original DITC for aftermarket computers, but If we can fully understand how it works.. we could make one which will fit in original place. And if we have complete docummentation for DITC we could easly repair it or tune to orginal settings without spending 800Euros on it

I think what to do next

maybe finnish print of PCB and go for ideological scheme... and after that I shuld be able to make some logical tables for whole unit.
_________________
931 82' - 5000km after full engine rebuild

SOLD: 924 81' N/A- with turbo gearbox "dogleg" - great but mysterious car

www.mauser98k.internetdsl.pl - if someone like german rifles (English version avalible)

Min · Posted: Sun Feb 21, 2010 7:09 am Post subject:

Now this is hardcore, hats off to you guys seriously. Reverse engineering is very difficult work.

Min
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Custom means it didn't come from a box.
1980 n/a with EDIS and Megasquirt II Injection. 7 different colors and counting.

Cedric · Joined: 27 Aug 2004 Posts: 2610 Location: Sweden

This must be the best thread on the board at the moment Great work!
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1980 924 Turbo
www.instagram.com/garagecedric/

RC · Joined: 25 Mar 2007 Posts: 2636 Location: Australia

McGyver · Posted: Sun Feb 21, 2010 7:30 pm Post subject:

I check forward voltage for that diode and it was something about 0,92-0,93V so it's to much for shottky. Yes I'm quite sure TK is Telefunken.
This diode can't be made specially for DITC's becouse I've got different two diodes from two different manufacturers in the same place.
Take a closer look to sing writen under that diode on PCB. It's a little wider than the rest diode signs, and definitely it's not the Zener sign what could be checked under that 4,7 zener diode.
I think that strange diode could have some capacitor inside - or how it names

capacitor-diode? I think we find something soon

Definitelly it's not zener - I checked it to 20V on puncture voltage and nothing happends.

I make photos of that diodes - 1'st and 2'nd... is that what we talking about.
Third is standard diode used in most parts of PCB and last is that Zener diode which gives 4,7V to our DITC's

I'm little lazy last times

And that's what I finish for now... complete mess whatever it is

_________________
931 82' - 5000km after full engine rebuild

SOLD: 924 81' N/A- with turbo gearbox "dogleg" - great but mysterious car

www.mauser98k.internetdsl.pl - if someone like german rifles (English version avalible)

RC · Joined: 25 Mar 2007 Posts: 2636 Location: Australia

That pic of the mystery diode #2 sure looks like a common (1A) GP rectifier, but considering the vintage it`s really anyones guess as sizes were usually much larger than today. The #1 pic of the diode in same location appears to be glass? Can`t read full ID on it anyway. At 0.93 FV agree that it`s not a schottky. If other zeners are marked on PCB with correct symbol and that one is just diode, very good chance its not a zener. Also most unlikely a zener would be over 20V unless it is for overvoltage/ spike protection. As the circuit diagram develops the location should give more indication. You are drawing a schematic, I presume?

Have looked at some early and/or obsolete listings of different prefix series and nothing with "457" comes up except a "1S457". Google can`t find me a data sheet without paying for it.

However my first guess of a 1N457 is looking like a good candidate, physical size, application and FV. Allowing for different meter current, capacitance, and other variables your forward voltage of 0.923 is on par with the 1.0V spec.

McGyver · Posted: Tue Feb 23, 2010 3:32 pm Post subject:

1N457 should be that what we need. I found somewhere datasheet for it and that's look good.
Yes the PCB is double sided with just 4 optional jumpers. I almost finish bootom layer and right now I have to complete top side, and the worst thing will be check everything at least two times to make sure everything is made ok. After that I'll have to change track width and profiles to make sure they're strong enough for currents in DITC.
I planed to draw the scheme for it but this take some more time - it's not to easy to do it but should reveal how inputs/outputs work

Work in progress....
_________________
931 82' - 5000km after full engine rebuild

SOLD: 924 81' N/A- with turbo gearbox "dogleg" - great but mysterious car

www.mauser98k.internetdsl.pl - if someone like german rifles (English version avalible)

Sentinal · Posted: Sat Apr 17, 2010 1:36 pm Post subject:

I find this whole thing very interesting. So out of curiosity if, i mean when, you get it all sorted as to how the gates work would it be possible to input that information into a plc with fbd capability to work as an ignition computer? Storing two or three maps into it and changing them with a switch may be quite easy would it not?
_________________
'81 931
'98 Dakota
'05 325xi

stevekat · Joined: 19 Jan 2008 Posts: 719 Location: Los Angeles, CA

How is this project coming?
_________________
"Never get out of the boat. Absolutely goddamn right. Unless you are goin' all the way."

Gone to new home: '81 924T, US version, CGT Intercooler, UTCIS-PT, Euro DITC, Greddy Trust MBC, Forged Fuchs Flat Dish 6's, Factory Recaro's.

michal928 · Joined: 10 Sep 2008 Posts: 41 Location: Warsaw

The project died... One of the two DITC`s was disassembled and the result of this experiment we can see on this topic. The second he was repaired and he use it in his car... He stole my idea and the one of the DITC those adressed for me from one of the person from forum. I can not experiment because I have not bad DITC - I can not disassemble my good DITC from my car... He is no serious man who is like to be in the center of the spotlight. Now he have new idea to produce center caps for alloy wheels - by the way - the idea who he stole from any other forum person in Poland...
The idea for build DITC was an enthusiasm for short time (IMHO center caps too). It is brutal but true...

ic932 · Joined: 11 Feb 2005 Posts: 1104 Location: UK

michal928 · Joined: 10 Sep 2008 Posts: 41 Location: Warsaw

Ic932 - i bought from you an ECU but for my friend who is older man and he have 931 in good but not working condition. I have not any DITC to start project from scratch - McGuyver done the project all alone.
I thought that McGuyver (Michal from Poland too) will finish work on the project despite this unpleasant fact of DITC theft sent from Nein but now he is silent.
I can start working on DITC on winter - now i have many work with friends cars. I must finish the project of the foto time counter for our porsche race in september and now i have not time.
Maybe McGuyver will finish work or only give as a circuit diagram of the DITC - this will save many time of hard work to understand "how ditc work", "how convert it to 937" and maybe save the ignition map of series ecu.
I would ask administrators about security because McGuyver can delete your own posts with important information.

ic932 · Joined: 11 Feb 2005 Posts: 1104 Location: UK

Nein37 · Joined: 29 Dec 2009 Posts: 513 Location: New London, CT

Damn the two free DITCs will come to nothing.

BTW consider one of those units as a donation from Ideola, he hooked me up in my time of need and freed up the second damaged unit to be donated.
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1981 931 CGT replica, OEM CGT intercooler, .8 BAR WG spring, GTS Headlights, Innovative Wide band A/F, A/C delete, 16" Fuchs, Weltmeister 200lb lowering springs, Bilstein HDs front, Koni Sport rears.