This echoes my experience as well.
once I split the signal and sent the mb to Pa, boom!
mine is also an OG that I bought for £35 on eBay about 20 years ago 😉
As mentioned above by @Stub Mandrel, I'm not aware of a passive version.
Mine has the battery space as well, although I do know of a few that were 'fixed' - I've been tempted to cure mine many times.