Digital Dash Difficulties
01-08-2009, 01:05 AM
#16
soontobered84 - the control stalk is unchanged since I bought the car, but I can't say that it was never replaced. Do you know, or can you point me to where I can find out, what the differences are?
The last dash surgery was for a new ignition switch and pod lights along with cleaning the PCB and cable connections as well as a new vacuum actuator for the defroster. I don't recall any cables or misc wiring not being connected or seeming to be mismatched, and there have not been any problems in the months since it was done.
OTOH, I have never tried to invoke the diagnostic mode before, so I have no idea if it used to work properly.
Thanks.
Bob
The last dash surgery was for a new ignition switch and pod lights along with cleaning the PCB and cable connections as well as a new vacuum actuator for the defroster. I don't recall any cables or misc wiring not being connected or seeming to be mismatched, and there have not been any problems in the months since it was done.
OTOH, I have never tried to invoke the diagnostic mode before, so I have no idea if it used to work properly.
Thanks.
Bob
01-08-2009, 07:04 PM
#17
Bob,
Do you have a set of Jim Moorehouse's Technical CDs? If not then buy a set as it will be the best investment you will make to maintain your 928. You can get them direct from Jim or you can buy for Roger.
Within these CDs there is the diagnostic procedure for the Digital Dash. This manual give you full diagnostics and in my previous post it tell you how to jump the pins on the diagnostic plug to invoke the diagnostic programme.
Tails 1990 928S4 Auto
Do you have a set of Jim Moorehouse's Technical CDs? If not then buy a set as it will be the best investment you will make to maintain your 928. You can get them direct from Jim or you can buy for Roger.
Within these CDs there is the diagnostic procedure for the Digital Dash. This manual give you full diagnostics and in my previous post it tell you how to jump the pins on the diagnostic plug to invoke the diagnostic programme.
Tails 1990 928S4 Auto
01-08-2009, 07:18 PM
#18
Tails - Thanks. I have Jim's CD set as well as a set of the WSMs. The CD's were one of the first things purchased and are worth their weight in unobtainium. It is very handy to find things in them and then use the paper WSM as needed.
Unfortunately, none of the information or procedures in any of the documents that I have searched through (WSM, tech bulletins, etc.) has been of any help: my DD does not seem to work as described. I can not reset languages, metrics, or invoke diagnostic mode as detailed. The only function that seems to work is if I want to calibrate the fuel level indicator.
Still hoping....
Bob
Unfortunately, none of the information or procedures in any of the documents that I have searched through (WSM, tech bulletins, etc.) has been of any help: my DD does not seem to work as described. I can not reset languages, metrics, or invoke diagnostic mode as detailed. The only function that seems to work is if I want to calibrate the fuel level indicator.
Still hoping....
Bob
01-08-2009, 07:40 PM
#19
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You may have to change out the CB for another one like we did with Dean's car.
I may have one but its not cheap. New is about $1000 and they do have some of the early ones in Germany.
Not what you really wanted to hear 8>(
I may have one but its not cheap. New is about $1000 and they do have some of the early ones in Germany.
Not what you really wanted to hear 8>(
__________________
Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission?
George Layton March 2014
928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission?
George Layton March 2014928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
01-08-2009, 09:27 PM
#21
Hello Roger and Dean - Yes, that is a depressing thought. I will put up with it as it is if the only alternative costs $1K.
Alternately, and assuming that this problem is really due to some unknown element of the standard program modes that no one knows the secret method of exiting and not an actual PCB component failure, it would seem that reprogramming the on-board memory should restore "normal" functioning.
I have no idea what the ROM physically consists of, i.e., how many physical IC's, whether it is all EEPROM or contains other types as well. Even without schematics, the parts can be identified and reprogrammed from a known good board, assuming that there is no battery backed up RAM masquerading as EEPROM, and that the IC's are not custom and still have the manufacturers part numbers on them.
This is true even if they have to be unsoldered to be copied and programmed. I would guess that most, if not all of the parts on the PCBs are through-hole type, which simplifies matters, but FWIW, I have a commercial PCB desoldering station that can handle even very large SM parts. I also have PROM programmers of various types in storage. It's a PIA to drag the stuff out, but other than time, this would not be too difficult to do.
The process should be pretty simple: pull the ROMs (of whatever type) from both the failed unit and a known good unit; compare the contents of the "good" ROMs with the "bad" ROMs; and reprogram the "bad" ROMs (if EEPROM) and/or replace with new, as applicable, if the contents are not the same, or, forget the whole thing if they are identical as there is a problem other than some inadvertently set software switch(es) that caused the problem in the first place.
Unless someone comes up with the magic formula to coax my DD into normal functioning, my intentions are to play with various sequences of button pressing, stalk manipulating, and power on resets to see if anything helpful occurs. I might also hunt around for a used dash too, and if one is found, try to reprogram my old one as described above.
Bob
Alternately, and assuming that this problem is really due to some unknown element of the standard program modes that no one knows the secret method of exiting and not an actual PCB component failure, it would seem that reprogramming the on-board memory should restore "normal" functioning.
I have no idea what the ROM physically consists of, i.e., how many physical IC's, whether it is all EEPROM or contains other types as well. Even without schematics, the parts can be identified and reprogrammed from a known good board, assuming that there is no battery backed up RAM masquerading as EEPROM, and that the IC's are not custom and still have the manufacturers part numbers on them.
This is true even if they have to be unsoldered to be copied and programmed. I would guess that most, if not all of the parts on the PCBs are through-hole type, which simplifies matters, but FWIW, I have a commercial PCB desoldering station that can handle even very large SM parts. I also have PROM programmers of various types in storage. It's a PIA to drag the stuff out, but other than time, this would not be too difficult to do.
The process should be pretty simple: pull the ROMs (of whatever type) from both the failed unit and a known good unit; compare the contents of the "good" ROMs with the "bad" ROMs; and reprogram the "bad" ROMs (if EEPROM) and/or replace with new, as applicable, if the contents are not the same, or, forget the whole thing if they are identical as there is a problem other than some inadvertently set software switch(es) that caused the problem in the first place.
Unless someone comes up with the magic formula to coax my DD into normal functioning, my intentions are to play with various sequences of button pressing, stalk manipulating, and power on resets to see if anything helpful occurs. I might also hunt around for a used dash too, and if one is found, try to reprogram my old one as described above.
Bob
01-09-2009, 12:35 AM
#22
Bob,
As a thought why dont you try VDO, the manufactures.
I would suggest you have a look at the back of the cluster or inside the cluster to ascertain what model software it is as described in my post.
I would then check with VDO via their web site with what you find.
I have in the past gone onto European Manufactures web site and in some instances I have been able to access their library to find out what I need to know.
It is worth a try, they just may have the answer.
Tails 1990 928S4 Auto
As a thought why dont you try VDO, the manufactures.
I would suggest you have a look at the back of the cluster or inside the cluster to ascertain what model software it is as described in my post.
I would then check with VDO via their web site with what you find.
I have in the past gone onto European Manufactures web site and in some instances I have been able to access their library to find out what I need to know.
It is worth a try, they just may have the answer.
Tails 1990 928S4 Auto
01-12-2009, 05:10 PM
#23
Tails- Good idea to contact VDO. Thanks.
I spent some time over the weekend poking around the VDO (now Continental) websites without any results. Lots of very general information about new products.
I will send off an email request for information as well as telephone the US contact office this week. We'll see what happens.
Bob
I spent some time over the weekend poking around the VDO (now Continental) websites without any results. Lots of very general information about new products.
I will send off an email request for information as well as telephone the US contact office this week. We'll see what happens.
Bob
