Can he open a shop to repair audio-visual equipment?

This audio-visual equipment
may be used for permissible purposes or it may be used for haraam purposes,
such as looking at pictures of naked women or listening to music etc. 

Hence it is not permissible
to repair it for one whom it is known or thought most likely that he will
use it for haraam purposes, because Allaah says (interpretation of the
meaning): 

“do not help one another
in sin and transgression. And fear Allaah. Verily, Allaah is Severe in
punishment”

[al-Maa’idah 5:2]
 

The Standing Committee for
Issuing Fatwas was asked: I work as an electronic engineer and part of my
work is fixing radios, TVs, videos and other such equipment. I hope that you
can advise me about continuing in this work, knowing that giving up this
work will cause me to miss out on a great deal of experience and my
profession for which I have studied all my life, and I will be affected by
giving it up. 

They replied: The shar’i
evidence from the Qur’aan and Sunnah indicates that the Muslim must seek to
earn a living from good (halaal) sources, so you should look for a job where
the income from it is good. As for earning a living by doing the work that
you mentioned, this is not good, because this equipment is usually used for
haraam purposes. End quote. 

Fataawa al-Lajnah
al-Daa’imah (14/420). 

Based on this, if you can
choose the people for whom you will repair this equipment, so that this will
not be helping them in anything haraam, there is nothing wrong with that.
But if you will be repairing equipment for everyone who comes to you, that
is not permissible because most people use these machines for haraam
purposes. 

You should look for another
job in which you will be safe from falling into haraam or doubtful areas.
The one who gives up something for the sake of Allaah, Allaah will
compensate him with something better than it. Provision is already decreed,
so do not let the fact that it is slow in coming make you seek it by
disobeying Allaah, as the Prophet (peace and blessings of Allaah be
upon him) said: “The Holy Spirit (i.e. Jibreel) inspired to me that no soul
will die until it has been given its provision in full. Fear Allaah and be
moderate in seeking a living, and do not let the fact that it is slow in
coming make you seek it by disobeying Allaah, for that which is with Allaah
cannot be attained except by obeying Him.”  Narrated by Abu Na’eem in
al-Hilyah; classed as saheeh by al-Albaani in Saheeh al-Jaami’
no. 2085. 

And Allaah knows best.