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Sharp MZ-3500 Capacitor Replacement Guide

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Sharp MZ-3541 drives, MFD interface and power supply (SharpMZ.net)
An MZ-3541 with the drive cover removed; the power supply is in the ventilated cage (SharpMZ.net)

The Sharp MZ-3500 has electrolytic capacitors in its power supply unit and on the CPU board. Sharp's service manual lists the power supply's capacitors by reference number, C001 to C031, and the CPU board's capacitors by type only, without reference numbers or quantities.[1][2][3] The power supply schematic is not in the surviving scan, so the positions of the supply's capacitors have to be found on the board by their printed reference numbers.

Power supply unit

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The supply makes +5 V and +12 V with switching regulators and −12 V with a dropper circuit, all from the secondary of a mains transformer.[4] Sharp's parts list identifies each of its capacitors by a supplier's type code. The electrolytic codes read as rated voltage, series, capacitance in microfarads and tolerance (M, ±20 %), so 35ULB33-M is a 35 V, 33 µF part. The values in the table come from those codes; read the printing on each capacitor before ordering.

MZ-3500 power supply electrolytic capacitors (parts guide)
Ref Code in the parts list Capacitance Voltage
C004 KM50VRSN10000HR 10,000 µF 50 V
C008 50ULB10-M 10 µF 50 V
C009 10ULB220-M 220 µF 10 V
C015 35ULB33-M 33 µF 35 V
C016 10ULB1000-M 1,000 µF 10 V
C017 10ULB1000-M 1,000 µF 10 V
C018 50ULB10-M 10 µF 50 V
C019 50ULB10-M 10 µF 50 V
C025 25ULB330-M 330 µF 25 V
C026 25ULB330-M 330 µF 25 V
C027 35ULB220-M 220 µF 35 V
C028 25ULB220-M 220 µF 25 V

[2] The other capacitors in the list are small-value parts: the 50F2S types from 1,000 pF (102) to 0.15 µF (154), C002 and C003 (DE1107E222M250VAC, 2,200 pF for 250 V AC by their code), and C001, which is 0.22 µF 250 V in the 200 V supply and 0.1 µF 125 V in the 100 V supply.[2] C001's rating changes between the 100 V and 200 V units and C002 and C003 are coded for 250 V AC, so treat all three as mains-side parts and replace them only with parts of the same voltage and safety rating.

The circuit description does not say which capacitor does what, and the drawings in it use their own simplified labels (C1, C2, C5, C6), which are not the reference numbers in the parts list.[4] C004, the 10,000 µF 50 V part, is the largest capacitor in the list.

CPU board

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The CPU board list gives nine electrolytic types but no reference numbers, and the circuit diagrams print values beside the capacitors without numbering them.[3][5]

MZ-3500 CPU board electrolytic types (parts guide)
Sharp code Capacitance Voltage
VCEAAA1CW106Q 10 µF 16 V
VCEAAA1CW107M 100 µF 16 V
VCEAAA1CW336M 33 µF 16 V
VCEAAA1EW106M 10 µF 25 V
VCEAAA1EW107M 100 µF 25 V
VCEAAA1EW227M 220 µF 25 V
VCEAAA1HW105M 1.0 µF 50 V
VCEAAA1HW335M 3.3 µF 50 V
VCEAAA1HW475M 4.7 µF 50 V

[3] These positions can be read from the circuit diagrams:[5]

CPU board electrolytics located on the circuit diagrams
Position Value on the diagram Diagram
VDD (+12 V) rail to ground 220 µF 25 V 13-1, main CPU
VCC (+5 V) rail to ground 220 µF 16 V 13-1, main CPU
VCC (+5 V) rail to ground 100 µF 16 V, four of them 13-1, main CPU
VGG (−12 V) rail, negative end on VGG 100 µF 25 V 13-1, main CPU
ALARM input of the reset gate 1 µF 50 V 13-1, main CPU
Power-on reset network 1 µF 50 V 13-1, main CPU
TA7313 audio amplifier output to the speaker 100 µF 16 V 13-2, sub-CPU
µPD1990AC clock supply pin 33 µF 16 V 13-2, sub-CPU

[5] The diagram and the parts list disagree on the 220 µF capacitor on VCC: the diagram marks it 16 V, but the only 220 µF part in the CPU board list is rated 25 V.[5][3] Fit a 25 V part there. The sub-CPU diagram also shows several smaller electrolytics around the audio amplifier and the voice input; their markings are hard to read in the scan, so take their values from the board.

The MZ-1R03 graphic board, if fitted, has its own electrolytics: 16 V 100 µF, 16 V 33 µF and 25 V 100 µF types in its parts list.[6]

Recording your board's capacitors

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Because the CPU board list has no reference numbers and part of the sub-CPU diagram is hard to read, make your own list before removing anything:

  1. Photograph the CPU board and the power supply board from above in good light.
  2. For each electrolytic, write down its printed reference (if the board has one), its capacitance and voltage as printed on the sleeve, and the polarity mark on the board.
  3. Check the readings against the tables above. A capacitor whose value is not in the CPU board list, or whose voltage is lower than the list's for the same value, is worth a second look.
  4. Keep the list with the machine; it saves the work on the next repair.

Replacement procedure

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Warning: the power supply is connected to the mains. Unplug the machine before opening it.

  1. Unplug the mains cable and remove the top cabinet. The exploded view on parts guide page 3 shows the screws.[7]
  2. Note the settings of the service switches (A) and (B) and the user switches SW1 before working on the CPU board.[8]
  3. Take the power supply unit out of the machine to work on it, and photograph it first.
  4. Replace C004 and the other supply electrolytics with parts of the same capacitance and at least the same voltage, observing polarity.
  5. Refit the supply and check +5 V, +12 V and −12 V at the CPU board's test pins before reconnecting the drives and option boards.[9]
  6. For the CPU board, the drives and the MFD interface board have to come out first.[10] Replace the rail capacitors and the reset capacitors first, then the rest from your own list.
  7. Run the self-check described in the Sharp MZ-3500 Troubleshooting Guide afterwards.
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References

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  1. ↑ Sharp, Service Manual, Personal Computer Model MZ-3500, code 00ZMZ3500SM/E (File:Sharp MZ-3500 Service Manual.pdf). Hosted with a description at Sharp MZ-3500 Service Manual.
  2. ↑ 2.0 2.1 2.2 Sharp, MZ-3500 service manual (File:Sharp MZ-3500 Service Manual.pdf), parts guide, power supply unit, pages 7 and 8 (PDF pages 115 and 116): C001 0.22 µF 250 V (part 0AE30511353) or 0.1 µF 125 V (part 0AE30272391); C002 and C003 DE1107E222M250VAC; C004 KM50VRSN10000HR; C005 and C006 50F2S102K; C007 50F2S154K; C008 50ULB10-M; C009 10ULB220-M; C011 50F2S223K; C012, C013 and C014 50F2S103K; C015 35ULB33-M; C016 and C017 10ULB1000-M; C018 and C019 50ULB10-M; C020 50F2S223K; C021 50F2S332K; C022 50F2S472K; C023 50F2S103K; C024 50F2S472K; C025 and C026 25ULB330-M; C027 35ULB220-M; C028 25ULB220-M; C029 and C030 50F2S223K; C031 50F2S332K. There is no C010. The list stops at R035 at the foot of page 8; parts-guide pages 9 to 12 are not in the scan.
  3. ↑ 3.0 3.1 3.2 3.3 Sharp, MZ-3500 service manual (File:Sharp MZ-3500 Service Manual.pdf), parts guide, CPU PWB, page 6 (PDF page 114): VCEAAA1CW106Q 16 WV 10 µF; VCEAAA1CW107M 16 WV 100 µF; VCEAAA1CW336M 16 WV 33 µF; VCEAAA1EW106M 25 WV 10 µF; VCEAAA1EW107M 25 WV 100 µF; VCEAAA1EW227M 25 WV 220 µF; VCEAAA1HW105M 50 WV 1.0 µF; VCEAAA1HW335M 50 WV 3.3 µF; VCEAAA1HW475M 50 WV 4.7 µF; no reference numbers or quantities.
  4. ↑ 4.0 4.1 Sharp, MZ-3500 service manual (File:Sharp MZ-3500 Service Manual.pdf), section 9, power circuit description, printed pages 87 to 89 (PDF pages 80 to 82): mains input, fuse, noise filter, power transformer, three rectifier and smoothing circuits, +12 V and +5 V switching circuits with a shared oscillator, filter circuits, alarm circuit and −12 V dropper; the alarm circuit holds its output for a short time after power-off from the charge on its own capacitors.
  5. ↑ 5.0 5.1 5.2 5.3 Sharp, MZ-3500 service manual (File:Sharp MZ-3500 Service Manual.pdf), 13-1, main CPU and memory circuit diagram (PDF page 99): VDD to GND 220 µF 25 V; VCC to GND 220 µF 16 V and four 100 µF 16 V, with 0.1 µF (SC) 12 V for the 64K DRAMs; GND to VGG 100 µF 25 V; 1 µF 50 V on the ALARM input of the reset gate and 1 µF 50 V in the power-on reset network. 13-2, sub-CPU circuit diagram (PDF page 100): 100 µF 16 V between the TA7313 audio amplifier and the speaker; 33 µF 16 V on the supply pin of the µPD1990AC clock.
  6. ↑ Sharp, MZ-3500 service manual (File:Sharp MZ-3500 Service Manual.pdf), parts guide, MZ-1R03 graphic board, page 14 (PDF page 118): VCEAAU1CW107M 16 V 100 µF, VCEAAU1CW336M 16 V 33 µF, VCEAAU1EW107M 25 V 100 µF.
  7. ↑ Sharp, MZ-3500 service manual (File:Sharp MZ-3500 Service Manual.pdf), parts guide, exteriors, pages 2 and 3 (PDF pages 110 and 111): top cabinet (18) and screws (31); power supply unit (17); MFD unit (25) and its fixing angle (20).
  8. ↑ Sharp, MZ-3500 service manual (File:Sharp MZ-3500 Service Manual.pdf), section 8-4, printed pages 85 and 86 (PDF pages 78 and 79).
  9. ↑ Sharp, MZ-3500 service manual (File:Sharp MZ-3500 Service Manual.pdf), 13-1, main CPU and memory circuit diagram (PDF page 99): test pins for GND, VCC, VDD and VGG.
  10. ↑ My MZ-3541, SharpMZ.net—link(accessed 2026-10-21) "MZ-3541 Motherboard; floppies and MFD interface cards demounted".


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