not an alternative for 100dpi

Contrary to what the package description says, it is not enough to have xfonts-100dpi installed because those fonts have odd point sizes.

1) The release of Ubuntu you are using, via 'lsb_release -rd' or System -> About Ubuntu

Description: Ubuntu 14.04.5 LTS
Release: 14.04

2) The version of the package you are using, via 'apt-cache policy xfonts-75dpi' or by checking in Software Center

1:1.0.3

3) What you expected to happen

4) What happened instead

Warning: Cannot convert string "-adobe-helvetica-medium-r-*-*-10-*" to type FontStruct

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: xfonts-75dpi 1:1.0.3
ProcVersionSignature: Microsoft 4.4.0-43-Microsoft 4.4.35
Uname: Linux 4.4.0-43-Microsoft x86_64
ApportVersion: 2.14.1-0ubuntu3.27
Architecture: amd64
Date: Tue Dec 5 14:26:29 2017
PackageArchitecture: all
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 LANG=pl_PL.UTF-8
 SHELL=/bin/bash
SourcePackage: xfonts-75dpi
UpgradeStatus: No upgrade log present (probably fresh install)