Harman Studer D21m - Repair Guidelines and Hazards

VII
ESD / Repair
  • Whenperformingarepairbyreplacingcompleteassemblies,theremoved
assembly must be sent back to the supplier in the same packing material
in which the replacement assembly was shipped. If this should not be the
case, any claim for a possible refund will be null and void.
  • UnpackedESDsensitivecomponents should onlybehandled in ESD
protected areas (EPA, e.g. area for field service, repair or service bench)
and only be touched by persons wearing a wristlet connected to the
ground potential of the repair or service bench by a series resistor. The
equipment to be repaired or serviced as well as all tools and electrically
semi-conducting work, storage, and floor mats should also be connected
to this ground potential.
  • TheterminalsofESDsensitivecomponentsmustnotcomeinuncontrolled
contact with electro statically chargeable or metallic surfaces (voltage
puncture, discharge shock hazard).
  • Topreventthecomponentsfromundefinedtransientstressandpossible
damage due to inadmissible voltages or compensation currents, electrical
connections should only be established or separated when the equipment
is switched off and after any capacitor charges have decayed.
E Repair
  Byremovinghousingpartsorshields,energizedpartsmaybeexposed.For
this reason the following precautions must be observed:
  • Maintenancemayonlybeperformedbytrainedpersonnelinaccordance
with the applicable regulations.
  • TheequipmentmustbeswitchedoffanddisconnectedfromtheACpower
outlet before any housing parts are removed.
  • Eveniftheequipmentisdisconnectedfromthepoweroutlet,partswith
hazardous charges (e.g. capacitors, picture tubes) must not be touched until
they have been properly discharged. Do not touch hot components (power
semi con ductors, heat sinks, etc.) before they have cooled off.
  • Ifmaintenanceisperformedonaunitthatisopenedwhilebeingswitched
on, no un-insulated circuit compon ents and metallic semiconductor hous-
ings must be touched, neither with bare hands nor with un- insulated tools.
Certain components pose additional hazards:
  • Explosionhazardfromlithiumbatteries,electrolyticcapacitorsandpower
semiconductors (Observe the component’s polarity. Do not short battery
terminals. Replace batteries only by the same type).
  • Implosionhazardfromevacuateddisplayunits.
  • Radiationhazardfromlaserunits(non-ionizing),picturetubes(ionizing).
  • Causticeffectofdisplayunits(LCD)andcomponentscontainingliquid
electrolyte.
Such components should only be handled by trained personnel who are prop-
erly protected (e.g. protection glasses, gloves).