Sharp X1 Turbo Capacitor Replacement Guide
No Sharp service manual or parts list for the Sharp X1turbo was found on the Internet Archive or X1 Center. The values below are read from the schematic of the Model 20 and Model 30 (assemblies AICZ851CR/E and AICZ852CR/E) published in Oh!MZ, which X1 Center offers for personal use.[1] The Sharp Museum found that the Model 10's board is the same as the Model 20 and 30 board with parts left unfitted, and that its power unit is its own design; the floppy interface and the telopper were options on the Model 10.[2] Later X1turbo models (Model 40, turbo II and turbo III) are not covered by this schematic. Check every part against your own board before ordering. The power unit is not in the schematic.
Sub board
[edit | edit source]| Ref | Value as drawn | Circuit |
|---|---|---|
| C19 | 47 µF 16 V | Sound amplifier supply, from VCC1 through R8 (68 Ω) |
| C21 | 10 µF 16 V | Sound amplifier (Q1 and Q2, 2SC2308C) |
| C57 | 10 µF 16 V | Sound amplifier |
| C18 | 100 µF 10 V | External sound output |
| C20 | 100 µF 10 V | Sound output to the television |
| C39 | 33 µF 16 V | Power-on reset |
| C41 | 33 µF 16 V | External reset switch line (EX RESET SW) |
| C43 | 10 µF 10 V, tantalum | External interrupt switch line (EX INT SW) |
The sub board's power connector brings in VCC1, 12 V (VCC3) and −12 V (VCC4) from the power unit.[1]
Main board
[edit | edit source]| Ref | Value as drawn | Circuit |
|---|---|---|
| C6 | 100 µF 10 V | Clock chip (µPD1990AC, IC5) supply, beside the 2.4 V backup cell |
| C5 | 47 µF 16 V | Supply from VCC2, before diode D5 |
| C2 | 47 µF 16 V | Supply from VCC2, after diode D5 |
| C7 | 10 µF 16 V | VCC2 line, after diode D3 and R7 (10 kΩ) |
| C11 | 10 µF 10 V, tantalum | RC network with R18 (220 Ω) in the display timing logic beside IC72 and IC74 |
The second of the main board's three sheets, with the CRT controller and the graphics, attribute and kanji memory, shows no electrolytic capacitors.[1]
Floppy interface board (Model 20 and 30)
[edit | edit source]| Ref | Value as drawn | Circuit |
|---|---|---|
| C9 | 100 µF 16 V | 5 V input from the main board |
| C3 | 4.7 µF 50 V | Data separator (SED9421C0B) supply, after L1 (100 µH) |
| C17 | 47 µF 16 V | Timing capacitor of the LS123 one-shot (IC12), with R13 (68 kΩ) |
| C18 | 10 µF 16 V | RC network with R12 (2.2 kΩ) and diode D2 on the drive-control gates (IC8, 7438) |
Superimpose (telopper) board
[edit | edit source]The Sharp Museum traced a completely dead X1turbo to this board: its electrolytics had lost capacitance and loaded the 12 V supply until the power unit's protection shut it down. Removing one 1000 µF capacitor restored a sensible resistance across the board's 12 V input. That board was an early revision with extra parts, including electrolytics, added on the back, so your board may not match the schematic.[3] The test for this fault is in the troubleshooting guide.
| Ref | Value as drawn | Circuit |
|---|---|---|
| C911 | 100 µF 16 V | 12 V input from the power unit |
| C978 | 1000 µF 6.3 V | VCC1 input from the main board, after L907 (8.2 µH) |
| C910 | 100 µF 6.3 V | Beside the RGB gating (IC908, 74LS08) |
| C963 | 1 µF 50 V | Horizontal and vertical drive circuit (IC902, IX0181CE) |
| C964 | Printed as "108M", 16 V; the value is not clear on the scan | Horizontal and vertical drive circuit, pin 14 of IC902 |
| C917 | 10 µF 16 V | Horizontal and vertical drive circuit |
| C923 | 1 µF 50 V | Horizontal and vertical drive circuit |
| C926 | 2.2 µF 25 V, tantalum | Horizontal and vertical drive circuit |
| C927 | 100 µF 16 V | Horizontal and vertical drive circuit, beside R919 (100 Ω) |
| C905 | 33 µF 16 V | Beside Q902 (2SC1815) on the 12 V line |
| C908 | 22 µF 16 V | Beside Q905 and diode D905 |
| C1001, C1002, C1003 | 1 µF 50 V each | RGB input buffers (Q1004 to Q1006) |
| C941, C942, C944, C945, C950, C951, C960 | 1 µF 50 V each | Superimpose circuits (IC906 and IC907, IX0503CE) |
| C932, C934 | 1 µF 50 V each | Beside Q910 and Q911 |
| C940 | 47 µF 16 V | 5 V supply to the superimpose circuits |
| C977 | 10 µF 10 V, tantalum | Superimpose circuit (IC906) |
| C954 | 47 µF 16 V | 12 V supply to the video and chroma mixer (Q915, Q916) |
| C956 | 33 µF 16 V | Video and chroma mixer |
| C953 | 470 µF 16 V | Video output coupling |
| C902 | 10 µF 16 V | Video switch (IC901, TA7347) input 1 |
| C904 | 47 µF 16 V | Video switch (IC901) pin 7, beside the 9.1 V zener diode D904 |
| C928, C929 | 22 µF 16 V each | Black burst generator |
| C930 | 10 µF 16 V | Black burst generator |
The "1000 µF" capacitor the Sharp Museum removed matches C978 in value, but the museum does not give its reference, and C978 is drawn on the 5 V (VCC1) input, not the 12 V input.[3][1] On an early board, look for extra electrolytics on the solder side as well.[3]
Clock backup cell
[edit | edit source]The 2.4 V nickel-cadmium cell (BAT0005CE) on the main board is not a capacitor but leaks like one. Its removal and replacement are covered in clock backup battery.[1] The trimmer C4 (20 pF) beside the clock crystal is not an electrolytic.[1]
Power unit
[edit | edit source]No schematic or parts list for the X1turbo power unit has been published. The Sharp Museum reports that none of the X1-family machines it owns, from the first X1 to the X1turbo Z III, has had a power unit fail.[3] If you do work on it, unplug the computer, let the capacitors discharge and measure across the large ones before touching the board, and 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; see Sharp X1 Capacitor Replacement Guide.[4] The Model 10's unit gives 13.8 V for the cassette deck instead of the ±12 V of the Model 20 and 30, so the two are not interchangeable.[2]
Replacement
[edit | edit source]- Photograph each 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.
- C43, C11, C926 and C977 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, switch on with the telopper board's 12 V lead unplugged first, then with it connected, and check that the computer starts both times.
Related pages
[edit | edit source]- Sharp X1 Turbo
- Sharp X1 Turbo General Maintenance
- Sharp X1 Turbo Troubleshooting Guide
- Sharp X1 Capacitor Replacement Guide, for the first X1
- Sharp X1 Turbo Z Capacitor Replacement Guide
- Capacitor Failure Symptoms
References
[edit | edit source]- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 CZ-851C/852C(X1turbo)回路図(Oh!MZ誌), X1 Center—link(accessed 2026-10-21) Schematic of AICZ851CR/E and AICZ852CR/E from Oh!MZ, seven sheets. Sub board DUNTK3579DE01 sheet 1/2: power connector A (GND, VCC3 12 V, VCC4 −12 V) and VCC1; R8 68 Ω with C19 47 µ (16 V); sound amplifier Q1 and Q2 (2SC2308C) with C21 10 µ (16 V) and C57 10 µ (16 V); C18 100 µ (10 V) to EX SOUND OUT; C20 100 µ (10 V) to TV SOUND. Sheet 2/2: C43 10 µ (10 V) (TA) on EX INT SW; C41 33 µ (16 V) on EX RESET SW; C39 33 µ (16 V) power-on reset. Main board DUNTK3578DE01 sheet 1/3: µPD1990AC (IC5) with crystal X1 32.768 kHz, trimmer C4 20 pF and C3 22 pF; backup cell 2.4 V (BAT0005CE) with D1, D2 (1SS119) and R3 3.3 kΩ; C6 100 µ (10 V) at IC5 VDD; C5 47 µ (16 V) and C2 47 µ (16 V) either side of D5 (1SS119) from VCC2; C7 10 µ (16 V) after D3 (1SS119) and R7 10 kΩ on VCC2. Sheet 2/3: no electrolytics. Sheet 3/3: C11 10 µ (10 V) (TA) with R18 220 Ω between IC72 (LS14) and IC74 (LS74A). Floppy interface QPWBS3580CEZZ: C9 100 µ (16 V) on the 5 V input (M-1, M-2); C3 4.7 µ (50 V) on SED9421C0B VCC after L1 100 µH; C17 47 µ (16 V) with R13 68 kΩ on LS123 (IC12); C18 10 µ (16 V) with R12 2.2 kΩ and D2 (1SS119) to the 7438 gates (IC8). Superimpose board DUNTK3582DE01: C911 100 µ (16 V) on the 12 V input from the power unit; C978 1000 µ (6.3 V) on VCC1 (W3) after L907 8.2 µH; horizontal and vertical drive IC902 (IX0181CE) with C963 1 µ (50 V), C964 marked 108M (16 V) at pin 14, C917 10 µ (16 V), C923 1 µ (50 V), C926 2.2 µ (25 V) (TA), C927 100 µ (16 V); C905 33 µ (16 V) beside Q902 on the 12 V line; C908 22 µ (16 V) beside Q905 and D905; C910 100 µ (6.3 V) beside IC908 (74LS08); RGB input transistors Q1004 to Q1006 with C1001 to C1003 1 µ (50 V); superimpose ICs IC906 and IC907 (IX0503CE) with C941, C942, C944, C945, C950, C951, C960 1 µ (50 V); C932 and C934 1 µ (50 V) beside Q910 and Q911, C940 47 µ (16 V) on 5 V and C977 10 µ (10 V) (TA); video and chroma mixer Q915 and Q916 with C954 47 µ (16 V) on 12 V, C956 33 µ (16 V) and C953 470 µ (16 V) to the video output; video switch IC901 (TA7347) with C902 10 µ (16 V) at input 1 and C904 47 µ (16 V) at pin 7 with zener D904 (9.1 V); black burst generator with C928 22 µ (16 V), C929 22 µ (16 V) and C930 10 µ (16 V).
- ↑ 2.0 2.1 X1turbo model10, シャープ博物館 (Sharp Museum)—link(accessed 2026-10-21) The Model 10 (CZ-850C) had half its graphics RAM, the telopper and the RS-232C as options; its board is the same as the Model 20 and above with parts not fitted; its power supply is specific to it and provides 13.8 V for the cassette in place of ±12 V.
- ↑ 3.0 3.1 3.2 3.3 X1turboのよくある故障とその対処, シャープ博物館 (Sharp Museum)—link(accessed 2026-10-21) None of about six machines from the first X1 to the X1turbo Z III has had its power supply fail; a completely dead X1turbo may be caused by the telopper board; its many electrolytics lose capacitance and overload the 12 V supply, tripping its protection; removing a 1000 µF electrolytic brought the resistance across the 12 V supply to a reasonable value; the board was an early revision with parts, including electrolytics, added on the back.
- ↑ 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.