Sharp MZ-40K Capacitor Replacement Guide
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The Sharp MZ-40K has nine electrolytic capacitors on the main board and six more on the Option 1 sensor inputs. No parts list for the kit has been found; the values below are read from Sharp's schematic diagram.[1] The board was assembled by its first owner from a kit, so the fitted parts may not match the schematic exactly.[2] Check each part on the board before ordering.
Main board
[edit | edit source]| Reference | Value | Voltage | Position |
|---|---|---|---|
| C10 | 1000 µF | 16 V | Reservoir after the 1B4B1 bridge |
| C13 | 1 µF | 50 V | TA78005P regulator output |
| C11 | 4.7 µF | 25 V | AC clock input to TR1 |
| C16 | 10 µF | 16 V | TR2 circuit |
| C1 | 4.7 µF | 25 V | IC1 audio amplifier input |
| C9 | 4.7 µF | 25 V | IC1 audio amplifier |
| C3 | 22 µF | 16 V | IC1 audio amplifier |
| C7 | 22 µF | 16 V | IC1 audio amplifier |
| C4 | 470 µF | 16 V | IC1 output to the speaker |
Option 1 (MZ-40K1 sensor kit)
[edit | edit source]Each of the six sensor inputs, JK1 to JK6, has a 10 µF 16 V capacitor on its input transistor.[1]
| Reference | Value | Voltage | Input |
|---|---|---|---|
| C20 | 10 µF | 16 V | JK1 (TR5) |
| C19 | 10 µF | 16 V | JK2 (TR4) |
| C18 | 10 µF | 16 V | JK3 (TR3) |
| C23 | 10 µF | 16 V | JK4 (TR8) |
| C22 | 10 µF | 16 V | JK5 (TR7) |
| C21 | 10 µF | 16 V | JK6 (TR6) |
Procedure
[edit | edit source]- Disconnect the AC adaptor.
- Remove the cover and lift the board from its base.
- Note the polarity marking of each capacitor, then desolder it.
- Fit the new part the same way round, with the same capacitance and the same or a higher voltage rating.
- Reconnect the adaptor and check that the regulator gives 5 V and that the clock advances.[3]
Related pages
[edit | edit source]References
[edit | edit source]- ↑ 1.0 1.1 1.2 1.3 Sharp Corporation, MZ-40K schematic diagram, reproduced at Diagram MZ-40K, SharpMZ—link(accessed 2026-10-21) Also hosted as File:Sharp MZ-40K schematic diagram.jpg. Polarised capacitors: C1 4.7 µF 25 V; C3 22 µF 16 V; C4 470 µF 16 V; C7 22 µF 16 V; C9 4.7 µF 25 V; C10 1000 µF 16 V; C11 4.7 µF 25 V; C13 1 µF 50 V; C16 10 µF 16 V; Option 1: C18, C19, C20, C21, C22 and C23 10 µF 16 V. Non-polarised: C2 1000 pF, C5 0.033 µF, C6 0.0033 µF, C8 0.1 µF, C12 1000 pF, C14 0.1 µF, C15 100 pF, C17 0.0033 µF, C24 10,000 pF.
- ↑ The MZ-40K kit– SharpMZ and Richard Cornelius, SharpMZ—link(accessed 2026-10-21) Sold only as a kit, with 23 pages of assembly instructions in the German manual.
- ↑ Technical data of the MZ-40K, SharpMZ—link(accessed 2026-10-21) 5 V DC regulated supply; the AC from the power supply is used for the clock, so no DC supply can be used.
