mh01 wrote:... I wish there was a way to check the remote/VW sensor.....
Visit this post to obtain the IRM's datasheet: viewtopic.php?p=68843#p68843
After you study the IRM's datasheet you should be able to envision a bench setup to roughly check the IRM. An O-scope is really required but you might get an indication of activity via a DVM when the IRM is stimulated with a VWU (not the Remote). I think the DVM will read about half the Vcc level while the VWU's signal is being processed, and nothing otherwise.
I would guess your greatest hassle will be to figure out how to connect test leads to an IRM wired for Roomba use!
Very few (like 'one or two') of these IRMs have required replacement over years 2002 to present.
No schematic of this sensor's application circuit has been posted, but that circuit has been on my list of things to do for years. I spent time today tracing it out and can attest to the fact there are no active components between J23 (where the cable from the Bumper shell interfaces with the main_PCA) and the system's micro controller unit. No components in this circuit are stressed via heating or voltage, so there is little incentive for parts to fail.
The component that could be most disruptive, if suffering a huge value shift, is R197 (aft face of PCB, far left end of board at upper corner). You might verify its resistance is nominally 10k ohms.
Are you really convinced that the interface cable's three RED, BLU, BLK wired plug-sockets (of seven sockets connecting to "J1" on the Bumper's PCA) have continuity to the three sockets in J23's mobo plug?