Sinclair ZX80 General Maintenance: Difference between revisions
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[[File:ZX80_PCB_Top.jpg|thumb|right|300px|Sinclair ZX80 Mainboard (Issue 2)]] | [[File:ZX80_PCB_Top.jpg|thumb|right|300px|Sinclair ZX80 Mainboard (Issue 2)]] | ||
== | == Board Revisions == | ||
{| class="wikitable styledtable" | {| class="wikitable styledtable" | ||
! Revision !! PCB Markings !! Notable Differences !! Common Issues | ! Revision !! PCB Markings !! Notable Differences !! Common Issues | ||
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|} | |} | ||
== | == Power Supply & Regulator Care == | ||
The ZX80 uses a simple linear power supply: | The ZX80 uses a simple linear power supply: | ||
* '''PSU Part:''' Sinclair 9V DC Adapter (center negative) | * '''PSU Part:''' Sinclair 9V DC Adapter (center negative) | ||
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* '''C1, C2, C3:''' Logic supply filtering | * '''C1, C2, C3:''' Logic supply filtering | ||
== | == Capacitor Replacement Table == | ||
{| class="wikitable styledtable" | {| class="wikitable styledtable" | ||
! Position !! Value !! Voltage !! Notes !! Series/Type | ! Position !! Value !! Voltage !! Notes !! Series/Type | ||
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|} | |} | ||
== | == Voltage & Clock Test Points == | ||
{| class="wikitable styledtable" | {| class="wikitable styledtable" | ||
! Test Point !! IC/Pin !! Expected Value (±Tolerance) | ! Test Point !! IC/Pin !! Expected Value (±Tolerance) | ||
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|} | |} | ||
== | == Essential Tools == | ||
* Antistatic wrist strap & mat | * Antistatic wrist strap & mat | ||
* Multimeter (with continuity and voltage) | * Multimeter (with continuity and voltage) | ||
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* Isopropyl alcohol & brush (for cleaning) | * Isopropyl alcohol & brush (for cleaning) | ||
== | == Preventive Maintenance Checklist == | ||
# Power off and unplug the unit. | # Power off and unplug the unit. | ||
# Discharge static and open the case. | # Discharge static and open the case. | ||
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# Reassemble and test operation. | # Reassemble and test operation. | ||
== | == Common Faults & Quick Checks == | ||
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! Symptom !! Likely Cause !! Quick Check | ! Symptom !! Likely Cause !! Quick Check | ||
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|} | |} | ||
== | == Troubleshooting Flowcharts == | ||
# '''No Power''' | # '''No Power''' | ||
## → Check PSU output (9V) | ## → Check PSU output (9V) | ||