Here are logic 7 repair instructions for every 1

WOW! Great work Stuart!

Originally Posted by DriftGirl

WOW! Great work Stuart!

Thanks!

Been playing with this again today, I removed the EEPROMS and connected a logic analyser to the first 8 bits of the EEPROM address bus.



The logic analyser connects to A0 - A7, there are 16 address lines in total. I only have an 8 bit logic analyser though

Anyway... when the processor powers up it will instantly address the EEPROM and start executing code. The image below shows the address lines after power up.



For those of you familiar with HEX, the processor first addresses 0x00000001 of the EEPROM and increments the address by 1 every 500 micro seconds. There is no code there as the EEPROM is missing, so the processor just counts up until its reset by the watchdog IC.

This does prove now that the processor is working, before it would randomly hang at power up. I am suspecting an issue with the EEPROM or RAM addressing that is causing the issue.

Its a very strange setup, the RAM and EEPROM do not share the same address or data bus like conventional micro processor systems, and the upper address bits are controlled by flip-flops.

I hope to post the 'FIX' soon so I havent just filled this thread with worthless rubbish! wish me luck!

Stuart

I must say your doing a great job on your
Little project there Stuart

Sent from my GT-N7000 using Bimmer App

Thanks PAPER,

My mate reckons the amount of time I have spent on this I could have just filled out a load of online surveys instead and just bought a new amp! he's probably right!

Anyway, I fitted some PLCC32 sockets today so I can swap out EEPROMS easily, The two I removed from the card originally erase OK but one of them fails to program with an addressing issue. This definitely means one of them was faulty. The remaining one does program OK but still causes the processor to hang every now and then. When it does work the EEPROM sends out the right data.

I had a PLCC32 1Mbit intel EEPROM kicking around at work, I plugged that in and the address lines work fine, unfortunately its so old (1993) the new programmer wont program it with the software!

A correction to my earlier post, the EEPROM is addressed from A0 to A16, the start address or reset vector is at 0x00010000, thats where the processor starts reading the code from the EEPROM.

Anyway, I have ordered some new EEPROMS today, but some 3.3V ones instead, on the board you can swap a link so you can use 5V or 3.3V EEPROMS, the system is 3.3V but it uses resistors to protect the CPU from the 5V logic output when using the 5V EEPROMS. If this does ever work again at least the EEPROMS wont be damaged if the PSU goes wrong!

I will update when the new EEPROMS arrive and I get them programmed.

Stuart

Well, at last I have some good news!

Im trying not to get too carried away but i'm 99% sure Ive fixed it!

I dug out the old EEPROM programmer today and managed to flash some new EEPROMS with the code I managed to read from the old ones.

I fitted them to the board in then new IC sockets and switched ON, the processor giving the problems was addressing the EEPROM OK but the code was not presented on the output. The other EEPROM worked fine

After a bit of head scratching the new EEPROMS have a pin to make them go into a low power shutdown state, this was floating as the original EEPROM does not have this feature. I therefore shorted this to 5V and it started working!



This shows the processor card with the PLCC32 sockets fitted and the new intel EEPROMS (or FLASH memory to be correct). you may be able to see the little link on the left EEPROM. The other EEPROM has a slightly different part number, it seems to work OK with the shutdown pin floating. (this is only temporary till the proper 3.3V FLASH chips arrive).



The watchdog being kicked by the processor, this is the image from the scope thats connected in the previous picture. This is a healthy state and indicates both processors are running and executing the software stored in the memories.



MOST activity is now present at initial power-up for about 15 seconds, it then shuts down and waits till light is present at the fibre input.



And finally a thermal image showing the two processors warming up indicating they are running the code and on the right the DSP processor is also running now communication has resumed between the three processors.

I didnt have time this evening to assemble everything and try it in the car, the amplifier card need re-assembling which I will do tomorrow and try it out in the car. I hope this has fixed it at last!

Stuart

You are genius!!

Hey all I'm no where near as tech savey as u but I pulled mine and I see same corrosion but the rest of the board is fine
Did u ever get it to work

Sent from my SAMSUNG-SGH-I727 using Bimmer App

Hello @ all

Stuart you are great Now i have learn somthing more about the L7 System
Before i was replace only the TDA.

odd.....

thanks

Great info on this forum! Priceless.
I'm from Holland and i drive a 2004 735i with logic 7.
Few months ago my right sub was making noise and crackling. My right back door speaker didnt work for a longer time.
For About a week the whole logic 7 shut down and only the ASK works perfect ( replaced a new about a half year ago )
So i ordered the TDA 1562 for the right sub and the TDA 8563 for the back door speakers and soldered it on the board as the instructions on this forum.
I tested the amp but still doesnt work. So I think there is another problem in my amp because the whole amp is not working.
I see a lot of smart people on this forum reparing and experimenting with the logic 7 amp so I hope someone here can help me with my problem.
I'm sorry for my bad english hope you guys know what I mean and can help me with my problem.

Stuart - i have no idea what you are on about in your posts, but it sounds might impressive and hope it all works!
I've just bought a 645 cab and found the rear right speakers buzzing so looks like i might have a similar amp issue.
I plan to remove it and check for water damage first - whats the best/safest way of cleaning off any corrosion?
Thanks