Help! Hunt for EEPROM chip on my dash cluster

Thread Starter

Ollie Sharratt

Joined Aug 8, 2018
8
I have had numerous issues with my Aprilia RS125, however this one has been rather bothersome. After some water damage to the dash, the odometer suddenly rose from 21,000 miles to 44,000, completely insane! I'm after finding the EEPROM chip on the board, I have spent an hour or so digging around and finding out what each chip is, however there is one on the board I can find absolutely no information about?

If somebody can help identify this that would be greatly appreciated!

(As far as i can tell the inscription reads:
51A
PLIE
)
 

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Thread Starter

Ollie Sharratt

Joined Aug 8, 2018
8
It is legal in the UK as long as it is declared upon selling.

I will not have any chance selling the bike on at the 44000 miles it claims to have, gained 20,000 miles in the past year which is simply not possible.

In many cases, with the correct set up, it is possible to reprogram an EEPROM chip. Of course it depends on each individual set up, however I fancy simply trying.
 

Tonyr1084

Joined Sep 24, 2015
3,584
I've seen it done - re-flashing the chip. Here's the rub: The chip has a dual memory. If you change one memory set you will accomplish nothing. You have to know the procedure as well as the schematic for that chip. There are shops that specialize in gauge cluster repairs and replacements. When replacing a cluster they will take the old cluster and make the new cluster state the last known set of miles showing on the old one. Changing odometers in America has to be done by licensed shops that are licensed by the state. Usually the weights and measures department - whatever department that is.

I you walk into a shop and say "My odometer jumped 20,000 miles over night" I don't think they're going to believe you. Their licensing is at risk if they take you at your word and it turns out you lied to them. Bottom line, changing the numbers is not legal and also something I don't think AAC will allow as a topic once it becomes clear you're attempting to learn how to change the odometer - for whatever reason.
 

qrb14143

Joined Mar 6, 2017
112
As the TS said, as far as I am aware it is perfectly lawful to alter the odometer on a vehicle as long as it is declared when sold. It is common practice, particularly with agricultural equipment to simply replace a faulty odometer with a new one reading zero miles. It is generally obvious to a buyer that this has been done but it should be declared none the less.

I'm not a biker myself so I am unsure if a bike needs an MOT. If it does, the last recorded mileage will be on record anyway.
 

bwilliams60

Joined Nov 18, 2012
1,190
If you can post a picture of the entire board I may be able to help you. The chip you are looking at may be the EEPROM but I don't recognize that number. There are many 3rd party programmers that you can purchase fairly cheap on EBAY and other sites that will perform this task and usually comes with a good set of instructions. As long as you are following the laws of the land, it can be done and quite easily. I do instrument cluster work all the time and this is a common practice to reprogram EEPROMS so I dont think AAC should ban the topic. In fact it should be explored more because what you are going to see very soon is components that are programmed specifically to a vehicle. When you replace them, they must be written to the vehicle. That means when you go to the junk yard and buy a module for your car and put it in, it wont function until it is programmed. EEPROM programming is going to get bigger.
 

Thread Starter

Ollie Sharratt

Joined Aug 8, 2018
8
Thanks for the good responses. I have attached a picture of the entire board however it’s not the best picture. I have so far identified the majority of components on the board.

Bottom left is a voltage regulator - 78l05a
Middle left a NAND gate - 74ac00
Bottom is (I believe) a hex converter, however this I cannot be sure of - 5CA69TM HC14 G4
Right side top is an 8-bit parallel or serial-in shift register - HC165M
Thanks for the help so far, I have attached the picture.
 

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Thread Starter

Ollie Sharratt

Joined Aug 8, 2018
8
Also, luckily this board is going to be scrapped, I have another on the way to replace it. Would very much just like to apply a more correct representation of the millage on the new board.
 

Sensacell

Joined Jun 19, 2012
2,450
If the story really is that the odo jumped to double mileage, I would bet the manufacturer (Aprilia) would help you out with the problem.
That's a serious issue, they don't want it getting around. (oops too late!)

Messing around with EEPROMs is going to be a very steep uphill climb, you have no idea how or where the data is stored, or how it's formatted.
 

Thread Starter

Ollie Sharratt

Joined Aug 8, 2018
8
I wish!

Aprilia, firstly there is no where in the UK. Secondally - there is very clear water damage and a capacitor failure on the board, which I believe caused the issue in the first place.
 

bwilliams60

Joined Nov 18, 2012
1,190
Tonyr is correct. It is most likely the one in the top left corner and it will have 8 legs. It may have a number like 95020 or something like that. It is programmable and not a steep learning curve if you buy the correct programmer. The other option when working with clusters is to just remove it and put it on the replacement cluster to keep the mileage proper. Your problem is different however and if the voltage doubled as you say, you have bigger problems going on and the EEPROM is probably corrupt. You can format and rewrite it but that get a whole lot more complicated and still may not fix your problem. Cheers.
 

ebp

Joined Feb 8, 2018
2,332
Three bytes is sufficient for 1.6 million kilometres at a resolution of 0.1 km. Four bytes gets you about a third of a billion km. About 101 out of 100 modern microcontrollers have vastly more than enough on-chip, so there is no need for an external EEPROM.
 
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