Rainsoft Q2 PCB: Used Working Part? or Repair Service Provider?

[Well-man]

We are the original owners of a well-maintained Rainsoft softener, which has reliably provided soft H2O for 35 yrs. The valve has been reliable. The only issue is the electronic control head. We have two Q2 PCBs.
- First one died about 7 yrs ago. Off the top of my head, I don't recall its specific issue. I've retained it for spare parts.
- Purchased a used one which worked perfectly until a week ago. It has blown its 1/2 amp 3AG fuse 2x in a week. Called my local Rainsoft distributor who supplied the used Q2 and he no longer has used replacements. His only solution is to upgrade our softener to the new current model valve & control head.
Qs:
- What typically causes the fuse is this specific part/application to fail?
- Is there a source for working used Q2 PCBs - part #200B?
- Or, is there a recommended US service provider that repairs water softeners / appliance PCBs?

Thanks!

 

[ditttohead]

Can you post a picture of the valve and board?

 

[Sponsor]

 

[Well-man]

Can you post a picture of the valve and board?

https://inspectapedia.com/plumbing/Rain-Soft-Water-Softener.jpg
https://duckduckgo.com/?q=rainsoft+Q2&atb=v43-1&iax=images&ia=images&pn=1

 

[ditttohead]

Unfortunately, I would have no idea where to find parts other than calling a bunch of old Rainsoft dealers. I am sure one of them will have the part in the yard. I checked with a couple of my buddies who did Rainsoft, nothing.

 

[Well-man]

Thanks for trying!

 

[Well-man]

Does anyone know:

• What typically causes the Q2 PCB 1/2 amp 3AG fuse to blow?
  
• Which component(s) typically fails on the Q2 control board?

My soldering skills are sufficient to replace individual components. However, on an initial visual inspection of the PCB, none of the components are obviously fried / burnt / discolored or damaged?

Thanks!