Hi,
I have a home burgler alarm which keeps resetting master code and all settings back to default when power is lost (battery and mains). It never used to do this so i have swapped the PCB with a spare which I had bought from ebay for parts a few years back.

I'm now interested in having a go repairing the old one to keep as a spare but this is a bit new to me so any help would be greatly appreciated.

It has a 93LC46 IC which i believe holds all of the user settings. Could i just replace this or do i need to to do additional programming prior to installation.
If needs be, i can pull the IC from my working one to read the stored code and then i guess i'd write it back to the new one.

I'm wondering where the factory default settings would be stored. Would they be on the same 93LC46 or stored elsewhere on the PCB?

Thanks

 

The 93L46c is an eeprom 1K memory by Pic Microsoft , this usually stores the user codes and engineers code, . You can remove it as it's in a socket. What is the make of alarm system?

 

The 93LC46 is a 1kb (64 x 16bit) serial EEPROM so is too small to store code so non-volatile storage of user data is its most likely purpose. Its guaranteed for 1million erase/write cycles and non-volatile for 200 years. If it is losing data then something is very wrong.

As they are very cheap (<50c) I'd try replacing it with a new one and see if it retains data.

 

Thanks for the reply. Would you just put a new (blank) one in first and try it without any programming? If it then needs copying the contents of my good one, i'll then have to get a suitable programmer

 

The 93L46c is an eeprom 1K memory by Pic Microsoft , this usually stores the user codes and engineers code, . You can remove it as it's in a socket. What is the make of alarm system?

Hi,
It's a Paragon Pyronix.

If it usually stores the engineer codes, i'm guessing i'll need to program it otherwise it won't know what the engineer, and other default codes are.

 

Engineer code is 9999, and user code is 1234 by Factory default.

Engineering manual

https://www.google.com/url?sa=t&sou...0QFnoECBsQAQ&usg=AOvVaw1D2Q5wrh6BK9VTr-WGEBmx

 

Hi,
Yes got all the factory codes and manuals. I'm just wondering whether they need to be programmed into the EEPROM prior to me replacing it.

 

I don't know if it requires reprogramming, but you could try a factory reset with the new chip in and see if it loads the codes .

 

Good thinking. I'll give it a go.

 

Thought I'd report back.
Changed the 93LC46. The one they sent me had a B on the end. Not sure if that made any difference so tried it anyway.

Reset to factory settings and now all works normally retaining all my user settings and codes even after full power loss for extended period of time.

Thanks to all for the advice.

 

Changed the 93LC46. The one they sent me had a B on the end. Not sure if that made any difference so tried it anyway.

The original version, without A or B suffix used the ORG pin to determine whether 8 x 128 or 16 x 64 organisation. The later A version is only 8 x 128 and B is 16 x 64. Pure luck it seems that you got the right one unless the software is clever enough to work with either. The even later C version is similar to the original, being able to be either organisation.