Billval acceptor jam / red led flashes 4 times

[vmintx]

Newbie here with billval acceptor jam after machine idle for a year, replacing batteries and performing a Ram clear.
Bought Purple Rain Quick Hits 5-reel in 2016. Mfg date: 09/06
S9-1 on metal plate on side of machine. (S9000?)
Billval label: 0508051275 UBA-11-SS   500-00-020f   USA-03
On side of BV old label UBA-10-SS ID003 V1.71-16 (AD30)
EPROM label UBA 10/11 ID-003 (1db4c) V251-49
Metal cash box

Hubby is former Navy Nuke electrician then AT&T phone tech. He has tools I don’t understand. Between the two of us, the BV and cash can has been cleaned within an inch of its life with lint free cloths, q-tips damped with water and a canned air blower from hell. No joy. Although we got all kinds of dust, fluff and a soldering braid out of the BV, the error persists.

What’s next? Buy a replacement BV? I’ve been looking at buying another BV but because I don’t know the exact meaning of the numbers “UBA-11-SS   500-00-020f   USA-03”, I don’t know which one to buy that would be compatible. Do the numbers on the replacement BV have to be exactly the same?

Any help you suggest is greatly appreciated. The slot machine worked perfectly until it got side-lined for a year. Not moved so nothing got dislodged. It just sat idle while the family focused on other things like medical issues, both in our family and at work.
Help?
Ordered a new BV from someone who says that although it’s not exact, it’ll work. We’ll see about that when it gets here.
It works! And the dead Bally Alpha has risen from the dead. Yay!