Sharp X1C Capacitor Replacement Guide
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No Sharp service manual or parts list for the Sharp X1C family was found on the Internet Archive or X1 Center. The values below are read from the complete schematic headed "X1C" on pages 279 to 283 of the book X1システム研究室 (Nihon SoftBank, 1985).[1] That schematic includes the kanji ROM, the two I/O slots and the IX0489CE gate array, which X1 Center lists for the X1Cs (CZ-803C) and X1Ck (CZ-804C), and X1 Center describes it as the X1Cs and X1Ck schematic.[2][3] The plain X1C (CZ-801C) has different graphics memory and fewer custom chips, so its board may differ.[3] Check every part against your own board before ordering. The power unit is not in the schematic.
Main board
[edit | edit source]| Ref | Value as drawn | Circuit |
|---|---|---|
| C16 | 100 µF 10 V | VCC1 (5 V) at the power input connector |
| C17 | 10 µF 10 V, tantalum | VCC1 at the power input connector |
| (unnumbered) | 10 µF 10 V, tantalum | VCC2 at the power input connector |
| C50 to C127 | The schematic gives the range for the decoupling capacitors, not each value | Supply decoupling across the board |
| C38 | 1 µF 50 V | Decoupling beside the IPL ROM (IC6) |
| C39 | 100 µF 10 V | Clock chip supply |
| C43 | 47 µF 10 V | Clock chip supply, after diode D5 from VCC2 |
| C22 | 47 µF 10 V | Sound circuit supply (through R22, 10 Ω) |
| C19 | 10 µF 16 V | Sound: volume control to the amplifier |
| C3 | 10 µF 16 V | Sound amplifier |
| C20 | 10 µF 16 V | Sound amplifier |
| C21 | 47 µF 10 V | Sound amplifier output to the speaker |
| C131 | 47 µF 16 V | Sound buffer Q4 |
| C29 | 47 µF 16 V | Sound buffer Q4 |
| C24 | 100 µF 10 V | External sound output |
| C30 | 100 µF 10 V | Sound output to the television |
| C26 | 0.47 µF 35 V, tantalum | RC network with diode D4 and R33, beside the 8255 (IC70) |
Kanji ROM section (X1Ck)
[edit | edit source]| Ref | Value as drawn | Circuit |
|---|---|---|
| C400 | 33 µF 16 V | VCC1 supply to the kanji ROM section |
Cassette interface
[edit | edit source]The cassette interface takes a 12 V supply (VCC3) from the power unit for the deck's solenoids and motor.[1]
| Ref | Value as drawn | Circuit |
|---|---|---|
| C210 | 100 µF 16 V | VCC3 (12 V) input from the power unit |
| C202 | 47 µF 10 V | Data recording circuit supply |
| C204 | 22 µF 16 V | Data playback circuit |
| C208 | 22 µF 16 V | Data playback circuit |
| C209 | 47 µF 10 V | Data playback circuit |
| C212 | 22 µF 16 V | Tape-end detection circuit supply |
| C220 | 10 µF 16 V | Tape-end detection circuit |
The graphics V-RAM section and the I/O slot section of the schematic show no electrolytic capacitors.[1]
Clock
[edit | edit source]There is no clock backup battery in the X1C, X1Cs or X1Ck, so there is no cell to remove or leak.[3] The trimmer C41 (20 pF) beside the clock crystal is not an electrolytic; if the clock will not start, see clock faults.[1]
Power unit
[edit | edit source]No schematic or parts list for the X1C power unit has been published. To work on it, unplug the computer, let the capacitors discharge and measure across the large ones before touching the board, then record each capacitor's reference, value, voltage, temperature rating, size and polarity before removing any. For the first X1's supply, X1 Center found that the large primary capacitor had lost 12 per cent of its capacitance while the others measured normal, and tested the repaired supply from a current-limited source; see Sharp X1 Capacitor Replacement Guide.[4]
Replacement
[edit | edit source]- Photograph the board before removing anything, and work on one board at a time.
- Replace one capacitor at a time, checking the polarity marking on the board against your photographs.
- Where your board's part differs from the tables above, follow the part on the board.
- C17, the unnumbered VCC2 capacitor and C26 are drawn as tantalum parts. Replace them with tantalum or electrolytic parts of the same value and at least the same voltage, and observe polarity.
- After the work, check the supplies at the connectors listed in the troubleshooting guide, then load a program from tape and test the sound.
Related pages
[edit | edit source]- Sharp X1C
- Sharp X1C General Maintenance
- Sharp X1C Troubleshooting Guide
- Sharp X1 Capacitor Replacement Guide, for the first X1
- Capacitor Failure Symptoms
References
[edit | edit source]- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 有田隆也 (Arita Takaya), X1システム研究室 (Nihon SoftBank, first edition 28 June 1985), pages 279 to 283, "X1C全回路図", in five parts. Kanji ROM part: C400 33 µ (16 V) on VCC1. Main part: power input connector I (GND, VCC1, VCC2) with C16 100 µ (10 V), C17 10 µ (10 V) (TA), a 10 µ (10 V) (TA) on VCC2 and C49 0.1; decoupling marked (C50 to C127); C38 1 µ (50 V) beside IPL ROM IC6; clock crystal X4 32.768 kHz with trimmer C41 20 pF (CTZ51F) and C40 22 pF; C39 100 µ (10 V); D5 from VCC2 with C43 47 µ (10 V); sound: R22 10 Ω with C22 47 µ (10 V), C19 10 µ (16 V) from the volume control R100, C3 10 µ (16 V), C20 10 µ (16 V), discrete amplifier Q1 to Q3, C21 47 µ (10 V) to the speaker, buffer Q4 (2SC2308C) with C131 47 µ (16 V) and C29 47 µ (16 V), C24 100 µ (10 V) to EXT SOUND OUT, C30 100 µ (10 V) to SOUND OUT for the television; C26 0.47 (35 V) (TA) with diode D4 (1SS119) and R33 (39 kΩ) beside the µPD8255AC-2 (IC70). Cassette interface part: P3 VCC3 (12 V) with C210 100 µ (16 V); data playback circuit with C204 22 µ (16 V), C209 47 µ (10 V) and C208 22 µ (16 V); data recording circuit with C202 47 µ (10 V); tape-end detection circuit with C212 22 µ (16 V) and C220 10 µ (16 V). Graphics V-RAM part: gate array IX0489CE and MB81416-12 memory; no electrolytics drawn. I/O slot part: buffers and connectors only. Scan on the Internet Archive, item x-1_TechnicalDocuments, leaves 281 to 285.
- ↑ 図面資料, X1 Center—link(accessed 2026-10-21) Schematic list: "CZ-803C（X1Cs）/CZ-804C（X1Ck）全回路図 ---> X1システム研究室 P279-283".
- ↑ 3.0 3.1 3.2 搭載チップセット, X1 Center—link(accessed 2026-10-21) CZ-801C (X1C): graphics RAM 6 × TMS4416-12NL; custom IC IX0395CE; backup battery none. CZ-803C (X1Cs) and CZ-804C (X1Ck): graphics RAM 6 × MB81416-12; custom ICs IX0395CE, IX0489CE and IX0490CE; backup battery none.
- ↑ CZ800C電源修理・・・できなかった。, X1 Center—link(accessed 2026-10-21) First X1 (CZ-800C) supply: electrolytics replaced; the large first-stage primary capacitor had lost 12 per cent and the others were normal; tested from a current-limited source with a wattmeter.