Editing Acorn Z80 Second Processor (section)

== Capacitors ==

{| class="wikitable styled-table" style="width:100%; text-align:center;"
|+'''Polarised capacitors (service manual pp. 45 and 49)'''
! Board !! Ref !! Value !! Type !! Acorn part
|-
| Power supply || C1 || 4700 µF 16 V || Aluminium electrolytic, reservoir || (assembly 831,000)
|-
| Power supply || C5 || 47 µF 35 V || Aluminium electrolytic, output || (assembly 831,000)
|-
| Main board || C2 || 100 µF 6.3 V || Aluminium electrolytic, power-up reset timing with R1 || 620,101
|-
| Main board || C3 || 47 µF 10 V || Aluminium electrolytic, +5 V supply || 621,470
|-
| Main board || C10 || 10 µF 35 V || Tantalum || 613,101
|}

The other main board capacitors are ceramics: C4 10 nF, C5 and C7 33 pF, C8 1000 pF (the reset monostable with R7), C9 56 pF (the NMI clock delay with R9), C11 100 nF, which absorbs spikes on the overvoltage sense line, and 33 decouplers of nominally 47 nF. The power supply also has C6, 22 nF.<ref name="sm" /> Acorn's power supply flowchart measures the voltage across C3 when tracing a short, and its reset check names R1, C2 and D1 if the 0.1 s power-up transition is wrong. Replace C1 and C5 if the supply shows ripple or will not hold 5 V into the 10 ohm test load. See [[Capacitor Failure Symptoms]].