Drop-In VR1 LCD Contrast Control for Radio Shack / Tandy TRS-80 Model 100 & NEC PC-8201a & PC-8201 Documentation Overview and installation instructions to replace a faulty contrast control knob. Articlesv2.0a – How to install the Drop-In VR1 replacement LCD contrast control for the Radio Shack / Tandy TRS-80 Model 100 & NEC PC-8201a & PC-8201 [DEPRECATED] v1.0 – How to install the Drop-In VR1 replacement LCD contrast control for the Radio Shack / Tandy TRS-80 Model 100 & NEC PC-8201a & PC-8201 Doc navigationMy Things → Was this article helpful to you? Yes No How can we help? Name Email subject message