HP 28S is very loud when opening/closing

[burkhard]

Yes, he meant flat top "2/3 AAA". I had suggested them to him somewhere on here (PM?) as I find that they are a little bit shorter than the N cells and thus put less stress on that evil "designed to fail" battery door interface. I use them in my perfect 28 and they seem to significantly reduce the spring preload. I charge them using ogazent N-cell adapters in a La Crosse BC-1000 smart charger. The N-cell adapters work fine for 2/3 AAA as well.

I'm also *very* careful opening the door.

Regarding a lubricant:
With both plastic and electronics, one always has to be a little careful as far as lubricants are concerned. I use this low-viscosity silicone oil for many plastics applications and have yet to have it cause any trouble. I haven't tried it on squeaky clamshell HP hinges... yet, but I think it would probably be a good application.
Super Lube 56104 Silicone Oil 100 CST, Clear
https://www.amazon.com/gp/product/B00OBV...UTF8&psc=1