Sharp MZ-2000 Capacitor Replacement Guide
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The Sharp MZ-2000 has electrolytic capacitors in its power supply, on the CPU board, in the display unit and on the cassette deck's control board, and on the optional MZ-1R01 graphics board and MZ-1U01 expansion unit. Sharp printed no parts list for the MZ-2000, but every value below is printed on the circuit diagrams in its owner's manual, hosted at Sharp MZ-2000 Owner's Manual.[1] Where the diagrams give no voltage rating, the tables say so.
Power supply
[edit | edit source]| Ref | Capacitance | Voltage | Position in the circuit |
|---|---|---|---|
| C1 | 470 µF | 16 V | Reservoir after D1, input of the −5 V regulator IC1 |
| C3 | 100 µF | 10 V | Output of IC1 (−5 V) |
| C22 | 2200 µF | 25 V | Reservoir after bridge D21, +5 V regulator |
| C23 | 2200 µF | 25 V | Reservoir after bridge D21, +5 V regulator |
| C25 | 4700 µF | 10 V | +5 V output, after choke L21 |
| C26 | 33 µF | 35 V | Between pins 12 and 13 of the +5 V controller IC21 (TL494CN) |
| C42 | 100 µF | 25 V | Output of the +15 V regulator IC41 |
| C45 | 2200 µF | 35 V | Reservoir after bridge D41, +12 V regulator |
| C46 | 2200 µF | 35 V | Reservoir after bridge D41, +12 V regulator |
| C48 | 3300 µF | 16 V | +12 V output, after choke L41 |
| C49 | 33 µF | 35 V | Between pins 12 and 13 of the +12 V controller IC42 (TL494CN) |
[2] The value of C49 is crossed by a circuit line on the diagram; it reads 33 µF 35 V, the same as C26 in the matching position of the +5 V regulator.[2] The other capacitors on the board are film or ceramic parts, including C101 and C102 (0.047 µF, 125 V AC) across the mains input.[2] Replace those two only with mains-rated (class X) capacitors. Ohishi found the supply's capacitors glued in place on his machine, which makes them slower to remove.[3]
CPU board
[edit | edit source]| Ref | Capacitance | Voltage | Position in the circuit | Source |
|---|---|---|---|---|
| C1 | 100 µF | 16 V | +12 V line at the display connector CN2 | Figure 4-12 |
| C4 | 10 µF | 16 V | Switch input EXRESET, with a 1S1555 diode | Figure 4-11 |
| C5 | 10 µF | 16 V | Switch input BST, with a 1S1555 diode | Figure 4-11 |
| C31 | 100 µF | 16 V | −5 V at power connector CN7; positive lead to ground | Figure 4-15 |
| C32 | 100 µF | 16 V | +12 V at power connector CN7 | Figure 4-15 |
| C33 | 100 µF | 16 V | +5 V at power connector CN7 | Figure 4-15 |
[4] C31 sits on the −5 V rail, so its positive lead goes to ground. Fitting it the other way round puts reverse voltage across it.[4]
Display unit
[edit | edit source]The display board is in the raised upper cabinet. Its electrolytics, from figure 4-16:[5]
| Ref | Printed on the diagram | Reading | Notes |
|---|---|---|---|
| C2001 | 47µ/50V | 47 µF 50 V | Base of Q2002 (2SC1514) |
| C2003 | 10µ/250V | 10 µF 250 V | In the brightness network with R2008 |
| C2004 | 4700µ/16V | 4700 µF 16 V | +12 V input, after fuse F01 |
| C2005 | 1000/16V | 1000 µF 16 V | – |
| C2007 | 4 7/25V | 4.7 µF 25 V | Decimal point not visible in the scan |
| C2008 | 220µ/10V | 220 µF 10 V | At the vertical IC I2001 |
| C2009 | 2 2µ/16V | 2.2 µF 16 V | At I2001; decimal point not visible in the scan |
| C2010 | 1µ/35V (TN) | 1 µF 35 V | Marked TN on the diagram |
| C2013 | 4 7/25V | 4.7 µF 25 V | Decimal point not visible in the scan |
| C2014 | 22µ/16V | 22 µF 16 V | – |
| C2015 | 22µ/16V (M) | 22 µF 16 V | Marked M on the diagram |
| C2016 | 2200/16V | 2200 µF 16 V | At I2001 |
| C2017 | 10µ/25V | 10 µF 25 V | In series with coil L2001 |
| C2020 | 220µ/16V | 220 µF 16 V | After diode D2002 (V03C) |
| C2024 | 100/16V | 100 µF 16 V | – |
| C2026 | 3 3µ/25V | 3.3 µF 25 V | Decimal point not visible in the scan |
| C2036 | 220µ/16V | 220 µF 16 V | At pin 1 of flyback transformer T2002 |
| C2037 | 220µ/100V | 220 µF 100 V | A circuit line crosses the label |
| C2038 | 1/250V | 1 µF 250 V | – |
| C2039 | 47/50V | 47 µF 50 V | Base of Q2007, with zeners D2009 and D2010 |
| C2040 | 4 7µ/50V | Not certain | A circuit line crosses the label between the 4 and the 7; read the part on the board |
| C2044 | 4.7µ/50V | 4.7 µF 50 V | Audio input to I2002 |
| C2045 | 1000µ/16V | 1000 µF 16 V | Supply to I2002, through R2051 (12 Ω) |
| C2046 | 220µ/16V | 220 µF 16 V | At I2002 |
| C2049 | 33µ/25V | 33 µF 25 V | Pin 3 of I2002 |
| C2051 | 4 7µ/16V | 4.7 µF 16 V | At I2002; decimal point not visible in the scan |
| C2052 | 10µ/16V | 10 µF 16 V | With R2053, at pin 7 of I2002 |
| C2053 | 470µ/16V | 470 µF 16 V | Output to the speaker |
| C2056 | 10µ/16V | 10 µF 16 V | In series with R2060 (390 kΩ) |
[5] Decimal points have dropped out of several labels on this sheet: resistors print as "6 8K" and "1 5 (1/2W)" and capacitors as "015" for 0.015 µF.[5] The readings above with a gap in the printed value assume the same loss, and C2044 shows the point where it survives. Read every part on your own board before ordering, and record the marking. The board also carries 630 V and 500 V film parts (C2041, C2042, C2054) in the tube's supply circuits.[5]
Warning: the display board connects to the picture tube's anode circuit through the flyback transformer T2002. Discharge the tube before removing parts; see CRT Discharge Procedure.
Cassette control board
[edit | edit source]| Ref | Capacitance | Voltage | Position in the circuit |
|---|---|---|---|
| C1 | 47 µF | Not printed | Timing capacitor of a 74LS123 one-shot (IC2) |
| C3 | 33 µF | Not printed | Timing capacitor of a 74LS123 one-shot (IC2) |
| C9 | 10 µF | Not printed | Power-on clear of IC2 |
| C11 | 47 µF | Not printed | 5 V decoupling at IC3 (75452) |
| C12 | 22 µF | Not printed | Read amplifier IC6 (LM324) |
| C17 | 1 µF | Not printed | OSC pin 13 of controller IC7 (TC9121P), with R36 (68 kΩ) |
| C18 | 22 µF | Not printed | Read amplifier input, IC6 |
| C20 | 1 µF | Not printed | OPEN line, with R38 (220 Ω) |
| C22 | 100 µF | 16 V | 12 V supply |
| C23 | 100 µF | 25 V | 15 V supply |
| C24 | 100 µF | 16 V | 5 V supply |
[6] Choose replacement voltages from the rail each part sits on: the board runs from 5 V, 12 V and 15 V.[6]
Optional boards
[edit | edit source]| Board | Ref | Capacitance | Voltage | Position |
|---|---|---|---|---|
| MZ-1R01 | C90 | 100 µF | 16 V | −5 V; positive lead to ground |
| MZ-1R01 | C91 | 100 µF | 16 V | +5 V |
| MZ-1R01 | C92 | 100 µF | 16 V | +12 V |
| MZ-1U01 supply | C1 | 2200 µF | 35 V | Reservoir after bridge D1 |
| MZ-1U01 supply | C4 | 2200 µF | 35 V | Reservoir after bridge D1 |
| MZ-1U01 supply | C3 | 33 µF | 35 V | TL494CN controller IC1 |
| MZ-1U01 supply | C7 | 3300 µF | 10 V | +5 V output, after choke L1 |
Replacement procedure
[edit | edit source]- Unplug the machine, remove the two screws under the keyboard and raise the upper cabinet on its support arm.[8]
- Photograph each board and record the value, voltage and polarity of every electrolytic before removing it. On the display board, write down what the part itself says wherever the diagram's value is uncertain.
- Start with the power supply: the reservoirs C22, C23, C45 and C46, the outputs C25 and C48, then C1, C3, C26, C42 and C49.
- Replace C31 on the CPU board, and C90 on the MZ-1R01, with the positive lead to ground.
- Fit parts of the same capacitance and at least the same voltage rating. Where no rating is printed, use one comfortably above the rail the part sits on.
- Before reconnecting the boards, check +5 V, +12 V, +15 V and −5 V on the supply's output connector.[2] This has to be done with the upper cabinet raised, which Sharp's manual warns against because of the risk of damage and electric shock;[8] keep hands and probes clear of the supply's mains side and of the display board.
- Close up, switch on and check that the IPL opens the deck lid and shows Make ready CMT with no tape inserted.[9]
Related pages
[edit | edit source]- Sharp MZ-2000
- Sharp MZ-2000 General Maintenance
- Sharp MZ-2000 Troubleshooting Guide
- Sharp MZ-2000 Owner's Manual
- Sharp MZ-2200 Capacitor Replacement Guide
- Capacitor Failure Symptoms
References
[edit | edit source]- ↑ Sharp, MZ-2000 Owner's Manual (Japanese) (File:Sharp MZ-2000 Owner's Manual.pdf), section 4.4, circuit diagrams, printed pages 62 to 76 (PDF pages 63 to 77). The manual has no parts list.
- ↑ 2.0 2.1 2.2 2.3 Sharp, MZ-2000 Owner's Manual (File:Sharp MZ-2000 Owner's Manual.pdf), figure 4-18, power circuit (unit DBOXD0044PAZZ), printed page 70 (PDF page 71); also File:Sharp MZ-2000 power supply circuit (owner's manual).png: C1 470 µF 16 V; C3 100 µF 10 V; C22 and C23 2200 µF 25 V; C25 4700 µF 10 V; C26 33 µF 35 V; C42 100 µF 25 V; C45 and C46 2200 µF 35 V; C48 3300 µF 16 V; C49 33 µF 35 V (a circuit line crosses the printed value); non-electrolytic C2 0.1 µF 25 V, C4, C21, C41 and C44 0.1 µF 100 V, C24 and C47 330 pF 50 V, C27 and C50 0.1 µF 12 V, C28, C29 and C51 0.018 µF 50 V, C43 0.01 µF 50 V, C52 0.0022 µF 50 V; C101 and C102 0.047 µF 125 V AC across the mains on either side of line filter L101.
- ↑ MZ-2000モニタ交換計画, Nibbles lab. (Ohishi)—link(accessed 2026-10-21) The power supply's capacitors showed no bulging and were all glued in place.
- ↑ 4.0 4.1 Sharp, MZ-2000 Owner's Manual (File:Sharp MZ-2000 Owner's Manual.pdf), figure 4-11, CPU board (1), printed page 63 (PDF page 64): C4 and C5, 10 µF 16 V, in the EXRESET and BST switch inputs; figure 4-12, CPU board (2), printed page 64 (PDF page 65): C1, 100 µF 16 V, on +12 V at CN2; figure 4-15, CPU board (5), printed page 67 (PDF page 68): CN7 with −5 V, +12 V, +5 V and GND, and C31, C32 and C33, "100 µ / 16 V × 3", with C31 drawn with its positive side to ground on the −5 V line.
- ↑ 5.0 5.1 5.2 5.3 Sharp, MZ-2000 Owner's Manual (File:Sharp MZ-2000 Owner's Manual.pdf), figure 4-16, CRT display control, printed page 68 (PDF page 69). Values as printed; several decimal points are missing from the scan, and labels for C2003, C2037 and C2040 are crossed by circuit lines. Fuse F01 (2 A) on the +12 V input; flyback transformer T2002 (RTRNF2015TA); vertical IC I2001 (RH-IX0015TA); audio IC I2002 (RH-IX0243PA); speaker 32 Ω.
- ↑ 6.0 6.1 Sharp, MZ-2000 Owner's Manual (File:Sharp MZ-2000 Owner's Manual.pdf), figure 4-17, cassette tape deck control, printed page 69 (PDF page 70): C1 47 µF and C3 33 µF on the LS123 one-shots of IC2; C9 10 µF on IC2's clear input with R15 (3.3 kΩ) and D6; C11 47 µF; C12 and C18 22 µF around IC6 (LM324); C17 1 µF at the OSC pin of IC7 (TC9121P) with R36; C20 1 µF on the OPEN line with R38; C22 100 µF 16 V on 12 V, C23 100 µF 25 V on 15 V, C24 100 µF 16 V on 5 V. Voltage ratings are printed only for C22 to C24.
- ↑ Sharp, MZ-2000 Owner's Manual (File:Sharp MZ-2000 Owner's Manual.pdf), figure 4-21, MZ-1R01 RAM block, printed page 73 (PDF page 74): C90, C91 and C92, "16V 100µF × 3", on −5 V, +5 V and +12 V, C90 with its positive side to ground; figure 4-24, MZ-1U01 power circuit (unit DBOXD0048PAZZ), printed page 76 (PDF page 77): C1 and C4 2200 µF 35 V, C3 33 µF 35 V, C7 3300 µF 10 V.
- ↑ 8.0 8.1 Sharp, MZ-2000 Owner's Manual (File:Sharp MZ-2000 Owner's Manual.pdf), section 3.1, printed pages 36 and 37 (PDF pages 37 and 38): switch off and unplug, remove the two fixing screws under the keyboard, lift the upper part from the front and hold it on the support arm; do not switch on with it raised.
- ↑ Sharp, MZ-2000 Owner's Manual (File:Sharp MZ-2000 Owner's Manual.pdf), section 2.1.1, printed page 15 (PDF page 16): with no tape set, the lid opens and "Make ready CMT" is shown.