Sequential prophet 5 - Mechanical Procedures Page; General; Precautions

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Section I
Mechanical Procedures
1-0 GENERAL
This section shows how to remove the Prophet's main assemblies. Not all of the procedures given
here should be necessary at any one time. For most service situations you will only need to separate
the top and bottom panel assemblies and arrange them as shown in Figure 1-0. This configuration,
discussed in paragraph 1-2, allows access to all trimmers on PCB 4, VOICE BOARD (Figure 7-7).
For more extensive service you may have to "swingout" or completely remove PCB 4. Procedures
below show how to do either, also, how to remove the remaining assemblies: PCB 3, COMPUTER
BOARD. PCB 2. LEFT and PCB 1, RIGHT CONTROL PANELS. PCB 6. POWER SUPPLY BOARD (PSB),
and the KEYBOARD (KBD).
Generally, each procedure gives disassembly or removal instructions only. It is assumed that re¬
placement procedures are just the reverse.
Sections 2-5 of this manual assume that you are familiar with the Prophet's mechanical design as
covered in this section.
1-1 PRECAUTIONS
Observe the following precautions when working on the Prophet:
• To prevent damage to the top panel, keyboarder woodwork, use a carpetted or similarly-covered
work surface when opening the cabinet.
• Set S701, power switch, OFF, and check S702,115/230V, on the back panel of units 184 and above
before connecting to power outlet.
• Never switch line voltage with instrument power on.
• Trimming and tuning must, of course, be performed with power on. So, avoid the power supply
primary circuitry, which conducts lethal voltages.
• Switch power off before disconnecting or connecting any internal circuitry, or removing or in¬
stalling PCBs.
• Do not bend or strain the PCBs. Otherwise may cause tiny breaks in the printed circuit traces
which will be extremely difficult to find.
• To replace soldered components, switch power off. remove the PCB completely from the instru¬
ment and desolder from both sides. Use a vacuum syringe or DIP desolderer. Don't overheat the
pads. WORK CAREFULLY.
• Remember that in service position, the top panel assembly balances on its rear edges. Don’t
upset this balance by pushing too hard when trimming.
1-1