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Sharp PC-1360 Troubleshooting Guide

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Sharp PC-1360 main board capacitors (service manual)
Capacitors and the contrast control on the PC-1360 main board (Sharp service manual).

Fault-finding for the Sharp PC-1360. The PC-1360 has a self-check test program in ROM covering the display, the RAM cards, the keys and both I/O connectors, and Sharp's service manual adds current limits, an auto power-off check and a continuity check.[1][2][3]

Preliminary checks

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  • Check the cells: replace them below 5.2 V for the pair (2.6 V per cell). A RAM card's cell needs replacing below 2.5 V.[4]
  • Try each RAM card on its own, in each slot. The PC-1350's CE-201M and CE-202M cards do not work in the PC-1360.[1]
  • Copy anything important from slot 1 to slot 2, or save it, before running the RAM test, which destroys the contents.[5][2]

Built-in test program

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  1. Set the PC-1360 to RUN mode and switch it off.
  2. Hold the V, R, 7 and 1 keys together and switch on.
  3. Choose a test from the menu.[2]
PC-1360 test menu (Sharp service manual)[2]
Key Test Notes
1 Display Displays test patterns; check the LCD visually
2 RAM card Read-after-write test of slot 1, then slot 2; choose the card size (2, 4, 8, 16 or 32 KB) or skip. Reports "Operation succeed" with the range checked, or the address where an error occurred
3 KROM & RAM Shown in the menu, but Sharp says this test is for Japan only
4 Keys Press the keys of each strobe group (KS1 onwards) in turn; SHIFT and Q move to the next group
5 11-pin I/O Needs Sharp's test tool UKOGC3020CSZZ fitted to the 11-pin connector on the left side
6 15-pin I/O Needs the test tool fitted to the 15-pin connector on the right side

Sharp's notes on the test program:[2]

  • Power can be switched off only while the basic menu is displayed.
  • The contents of the RAM are destroyed by the test.
  • If the test program will not start, check the keys first.

The I/O tests drive each output and check that the matching input follows: on the 11-pin connector Xout to Xin, IO1 to IO2, IO2 to IO1, Dout to Din, Din to Dout and Busy to Ack; on the 15-pin connector RR to CD, RS to CS, SD to RD, PRQ to PAK and ER to RAK. "Operation complete" appears at the end even if there was an error, so read the error frame, and a pair of signals shorted together does not show as an error.[6]

Current consumption

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Sharp's current limits at 20 °C[4]
Condition Maximum
PC-1360, power off 25 µA
PC-1360, displaying 600 µA
PC-1360, calculating 4.3 mA
CE-212M RAM card About 25 µA

A machine that drains its cells while switched off should be measured against the 25 µA limit, with and without each RAM card.

Other service checks

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  • Auto power-off: press the ALL RESET key with the power on and type Y; check the display; leave the machine for 15 minutes and check that the display has gone off.[3]
  • Continuity: the resistance between the slot-2 side static panel and the right upper edge of the panel surface must be below 5 Ω.[3]

Display faults

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Display symptoms
Symptom Check
Blank display Cells against 5.2 V; current consumption; a RAM card in place[4]
Faint or uneven display The 20 kΩ contrast control; the three 1 µF capacitors and the divider resistors beside it[7]
Missing dots, lines or a block Run test 1; clean and reseat the LCD rubber connector (PGUMS1550CCZZ) before suspecting the LCD or its five SC43537 drivers[2][8][9]

Serial port

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The 15-pin port uses CMOS levels (4 to 6 V), asynchronous and half duplex at 300, 600 or 1200 baud. It needs a level converter for RS-232 equipment.[1][10] Test 6 checks it with Sharp's test tool fitted.[2]

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References

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  1. ↑ 1.0 1.1 1.2 Sharp Corporation, Service Manual, Model PC-1360, code 00ZPC1360SM/E, August 1986, sections 2 and 3, printed page 1 (PDF page 1). Hosted as File:Sharp PC-1360 Service Manual.pdf.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Sharp, Service Manual, Model PC-1360, section 9 "Test program", printed pages 7 to 9 (PDF pages 7 to 9).
  3. ↑ 3.0 3.1 3.2 Sharp, Service Manual, Model PC-1360, section 10 "Other test items", printed page 9 (PDF page 9).
  4. ↑ 4.0 4.1 4.2 Sharp, Service Manual, Model PC-1360, section 6 "Power consumption", printed page 3 (PDF page 3).
  5. ↑ Sharp, Service Manual, Model PC-1360, section 3 (continued), printed page 2 (PDF page 2): copy capability.
  6. ↑ Sharp, Service Manual, Model PC-1360, 11-pin and 15-pin I/O signal tests, printed page 9 (PDF page 9).
  7. ↑ Sharp, Service Manual, Model PC-1360, section 12 "Parts and signals position", printed page 12 (PDF page 12).
  8. ↑ Sharp, Service Manual, Model PC-1360, section 13 "Parts list & guide" (PDF pages 18 to 19).
  9. ↑ Sharp, Service Manual, Model PC-1360, section 5 "Block diagram", printed page 3 (PDF page 3).
  10. ↑ Sharp Pocket Computers, Printers, Cables, Level Converters & Accessories, sharppocketcomputers.com—link(accessed 2026-10-21) "Level Converters" section: needed to connect the PC-1360 or another calculator with a 15-pin SIO connector to a PC.


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