I am still looking for a schematic for a Simplex 4004 fire panel. It has problems with battery power. I need to find the issue and repair it.
I don’t want to replace it unless I have to. It will not charge the batteries. Please advise…
Please refer to the installation documentation from Firealarmresources.com
Note: It sounds like the charging circuit in the panel is bad. Get a multi-meter and check for DC voltage on TB3 where the battery connects. It should read around 27v to 29v. It it’s any lower the charging circuit has failed. The panel would need to be replaced as there is no user serviceable parts for it.