AB 1746-A10 SER A Replacment

I have two old Allen Bradley 1746-A10 SER A chassis networked together and one of the chassis (master) is acting up on occation. I need to replace this one chassis. What I'm looking for is what is the difference between the series A and the series B chassis. Can I replace the bad chassis with the series B without any noticable changes and will this change effect the second chassis that remains an A series.

Welcome to the Forum !

The 1746 chassis are functionally identical, so you can definitely install a Series B chassis in place of a Series A chassis.

The main change was a set of capacitors that are located underneath the CPU slot; take care inserting the CPU and the first module on the older chassis to be sure that these haven't bent out of place and aren't getting crushed. They should either be absent or mounted lower on the Series B.

When you refer to the chassis as "master" and "slave"; are they connected with a RIO "blue hose" network, or ControlNet, or one of the 3-foot-long chassis interconnection bus cables ?

Damaged or defective chassis are less common than worn out power supplies, but you have probably done some troubleshooting that points to the chassis.

Great, thanks for the information on the two chassis. To be honest I really can't remember what type of wire is connected between the two. This unit is at a remote site and I don't get there very often unless there are problems.

As for the power supply, that has just been replaced. We had a power outage in the entire area where this unit is located for a few days. During the outage we also had single phased and had other issues with the power. In the end we had blown numerous fuses in our control panel and the power supply for this chassis was completly dead when the power returned. After installing the new power supply, I noticed I was having problems with a few of the analog input cards not powering up properly and had to change slot locations. Thats the main reason I wanted to change the chassis. Our client is pushing us to find the least expensive replacmet for the unit. I have found numerous units available on line for approximately 50% less than the current new replacment costs.