Q: What does the "E" light mean on my OLIVETTI LOGOS 902 calculator? The device turns on but does not respond to the keys.

The "E" light on your OLIVETTI LOGOS 902 generally indicates an error or a mechanical blockage condition. Here are the most common causes and solutions: Immediate Checks Check the paper - Ensure that the paper roll is properly engaged in the right slot and that there is no crumpled or jammed paper inside. Remove and reinsert the roll completely. Check the paper sensor - Try using the calculator without paper : if the "E" light disappears and it responds to the keys, the problem lies with the roll or the sensor. Reset - Turn off the device completely, wait 10 seconds, then turn it back on. Sometimes a simple restart clears the error. If the problem persists If the device continues to display "E" after these checks, it is likely that an internal component is jammed (jammed paper roll, dirty gear) or there is a malfunction in the detection system. In this case, a thorough cleaning of the printing chamber or technical repair will be necessary. According to the user manual for the LOGOS 902, use only a dry cloth to clean the device - never use alcohol or liquids that could damage the electronic components.

Q: What does the 'error' message on the OLIVETTI LOGOS 912 printer screen mean?

The 'error' message appears when you try to enter a number with more than 12 digits . The LOGOS 912 printer has a maximum capacity of 12 digits and rejects any number that exceeds this limit. How to resolve the error: Press the [C/CE] button to clear the error and reset the screen Re-enter the number ensuring it does not exceed 12 digits If the error message persists after pressing [C/CE], check that the ink ribbon and paper are properly installed. This type of error is usually resolved by clearing it, but improper installation of consumables can cause malfunctions.

Q: How to set the tax rate using the RATE button on the OLIVETTI LOGOS 902?

On the OLIVETTI LOGOS 902, the tax rate is set using the [RATE] button (Tax rate/exchange), not directly with [TAX +] or [TAX -]. Steps to set the tax rate: Press and hold the [RATE] button for about 3 seconds until "RATE" flashes on the display. Press [EURO] to access the desired memory position (r-01 to r-13). Enter the desired rate value (for example, 20 for 20%). Press [EURO] again to confirm the programming. You can navigate between positions using the [+] or [-] buttons. Once the tax rate is set, you can use: [TAX +] to calculate an amount including VAT (according to the programmed rate). [TAX -] to calculate an amount excluding VAT.

Q: Why does the OLIVETTI LOGOS 694ΑT calculator perform an automatic multiplication when entering an addition?

The OLIVETTI LOGOS 694ΑT calculator has a constant calculation function that allows for repeated multiplications or divisions with a stored value. If you notice that a multiplication occurs automatically when entering an addition, it is likely that a constant calculation mode has been accidentally activated or misinterpreted. Probable cause: The constant calculation mode is intended to multiply or divide a number by a fixed value stored in memory. If this mode is active, entering a number and then pressing an operation key other than the standard addition may trigger a multiplication. Also, ensure you are using the correct keys: for a simple addition, you should use the [+]1 or [+]2 key depending on the chosen totalizer, not a special function key. Procedure for using simple addition: Enter the first amount to add Press the [+]1 key (or [+]2 for the second totalizer) Enter the next amount Press [+]1 (or [+]2 ) again Continue for all your additions To obtain the result, press [T]1 or [T]2 (Total key) If the problem persists: It is possible that a key is faulty or physically stuck, or that a memory function is programmed on your machine. Press the [C/CE] key twice to completely reset the calculator (this clears all contents, including totalizers and Grand total memory). Then test a simple addition to check that normal operation is restored. If addition still triggers a multiplication, consult a specialized calculator repair technician, as this may indicate a hardware malfunction or modified internal programming.

Question 1

What does the "E" light mean on my OLIVETTI LOGOS 902 calculator? The device turns on but does not respond to the keys.

Accepted Answer

The "E" light on your OLIVETTI LOGOS 902 generally indicates an error or a mechanical blockage condition. Here are the most common causes and solutions:

Immediate Checks

Check the paper - Ensure that the paper roll is properly engaged in the right slot and that there is no crumpled or jammed paper inside. Remove and reinsert the roll completely.
Check the paper sensor - Try using the calculator without paper: if the "E" light disappears and it responds to the keys, the problem lies with the roll or the sensor.
Reset - Turn off the device completely, wait 10 seconds, then turn it back on. Sometimes a simple restart clears the error.

If the problem persists

If the device continues to display "E" after these checks, it is likely that an internal component is jammed (jammed paper roll, dirty gear) or there is a malfunction in the detection system. In this case, a thorough cleaning of the printing chamber or technical repair will be necessary.

According to the user manual for the LOGOS 902, use only a dry cloth to clean the device - never use alcohol or liquids that could damage the electronic components.

Question 2

After changing the paper, my OLIVETTI LOGOS 914T printer is not printing. What should I do?

Accepted Answer

If the printer does not recognize the new paper and does not print anything after the change, here are the points to check as a priority:

Check the paper positioning: The thermal paper must be positioned correctly under the thermal head. The 57.5 mm wide paper must be properly aligned in the insertion slot on the right side of the calculator.
Unroll the paper correctly: According to the manual, you must first cut the initial edge of the roll straight, then unroll the paper from the bottom before inserting it into the slot. Press the paper feed button until it unrolls correctly, then place the roll in its holder.
Check the NP-P switch: Make sure the print selector is set to “P” (print mode). If the switch is not in the right position, the paper will not advance and the printer will not work.
Clean the thermal head: If there are paper residues on the thermal head, this can block printing. Use a dry, soft cloth to clean it. Never use alcohol or liquids.
Check the power supply: The device only works on AC power. Check that the power cable is properly connected and that the electrical outlet is functioning.

If after these checks the paper advances normally but the printer still does not print, the problem may be with the thermal head itself.

Question 3

What does the 'error' message on the OLIVETTI LOGOS 912 printer screen mean?

Accepted Answer

The 'error' message appears when you try to enter a number with more than 12 digits. The LOGOS 912 printer has a maximum capacity of 12 digits and rejects any number that exceeds this limit.

How to resolve the error:

Press the [C/CE] button to clear the error and reset the screen
Re-enter the number ensuring it does not exceed 12 digits

If the error message persists after pressing [C/CE], check that the ink ribbon and paper are properly installed. This type of error is usually resolved by clearing it, but improper installation of consumables can cause malfunctions.

Question 4

After changing the roll, the printer does not print - what should I do?

Accepted Answer

The problem usually comes from incorrect loading of the thermal paper. Here’s how to do it correctly:

Paper loading steps

Turn on the device and lift the printer cover
Prepare the paper: carefully cut or tear the initial part of the paper roll to have a straight and even edge
Insert the paper: hold the roll in one hand, unroll the paper from the bottom side of the roll, and insert it into the slot on the right side of the calculator
Engage the paper: press the paper feed button until the paper is properly engaged in the mechanism
Install the roll: place the roll in its designated holder

Important checks

If the printer still does not print after these steps:

Check that you are using thermal paper of the correct dimensions: width 57.5 ± 0.5 mm, maximum diameter 50 mm
Ensure that the paper is properly engaged in the feed mechanism
Check that no detached piece of paper is blocking the passage

Question 5

How to set the tax rate using the RATE button on the OLIVETTI LOGOS 902?

Accepted Answer

On the OLIVETTI LOGOS 902, the tax rate is set using the [RATE] button (Tax rate/exchange), not directly with [TAX +] or [TAX -].

Steps to set the tax rate:

Press and hold the [RATE] button for about 3 seconds until "RATE" flashes on the display.
Press [EURO] to access the desired memory position (r-01 to r-13).
Enter the desired rate value (for example, 20 for 20%).
Press [EURO] again to confirm the programming.
You can navigate between positions using the [+] or [-] buttons.

Once the tax rate is set, you can use:

[TAX +] to calculate an amount including VAT (according to the programmed rate).
[TAX -] to calculate an amount excluding VAT.

Question 6

Why is my OLIVETTI LOGOS 914T printer not printing anything?

Accepted Answer

If your OLIVETTI LOGOS 914T is not printing at all, here are the checks to perform in order:

1. Check the insertion of the thermal paper

The paper must be inserted correctly under the print head. According to the manual, you should gently tear off the initial part of the paper roll to obtain a straight and even edge, then position it under the thermal head. If the paper is not properly aligned or is missing, nothing will print.

2. Check the power supply

Ensure that the calculator-printer is properly turned on and connected to the mains. The 14-character LCD screen should display values or normal operating elements.

3. Test with a simple operation

Perform a basic calculation (for example: 1 + 1) and press the equals key to get the result and trigger printing. This allows you to check if the mechanism is working.

4. Clean the print head

If the paper is properly inserted and the device is powered, the thermal head may be dirty. Turn off the calculator for a few seconds, then gently clean the head with a dry cloth. Paper residue or dust can block thermal printing.

5. Check the width of the paper

This printer is designed for thermal paper that is 57.5 mm wide. If you are using paper of a different size, it will not be compatible and printing will not work correctly.

If after these steps the device still does not print anything, the thermal head may be defective or the printed circuit board damaged, and a repair will be necessary.

Question 7

How to disable or reduce the backlight of the LCD display?

Accepted Answer

The technical manual of the OLIVETTI LOGOS 694ΑT calculator does not mention any control or setting to adjust or disable the backlight of the 14-character LCD screen.

This device, dating from the 1970s-1980s, does not have a built-in software function to manage the brightness of the display. This is a common feature of desktop calculators from that era.

Possible alternatives:

If the brightness bothers you, you can slightly decrease the distance between your eyes and the screen or adjust the viewing angle
Check that the calculator is not overheating - the manual specifies that optimal operation is between 0-40°C
If the display seems abnormally bright, a technical check with the manufacturer can determine if it is a malfunction

Question 8

The LCD display shows a lot of zeros but the numbers I enter do not display correctly - how can I fix this?

Accepted Answer

This problem is characteristic of old liquid crystal LCD screens that degrade over time. Your OLIVETTI LOGOS 694ΑT calculator has a 14-character LCD screen, and this symptom usually occurs after several years of use.

Possible causes:

Degraded liquid crystals - after years, the liquid crystals lose their effectiveness, causing erratic display of some pixels (hence the visible zeros but the other numbers being invisible).
Overheating - according to the manual, the operating temperature range is 0-40°C. Make sure you are not covering the calculator while it is in use (risk of overheating) and that the area is well-ventilated.
Excessive humidity or exposure to sunlight - the manual recommends avoiding areas with high humidity, dust, and direct sunlight exposure.

Solutions to try:

Let the calculator rest for a few hours at room temperature, then turn it back on. Sometimes, the liquid crystals

Question 9

How to correctly insert paper into the OLIVETTI LOGOS 912 printer?

Accepted Answer

The OLIVETTI LOGOS 912 is a printing calculator that works with a paper roll, not standard sheets. The paper must measure precisely 57.5 ± 0.5 mm in width and 50 mm in diameter. You will find the compatible paper accessory code: 81120.

Before inserting the paper, you need to prepare its edge. Carefully cut or tear the initial part of the paper roll to obtain a straight and even edge. This preparation is essential to ensure proper feeding of the paper under the print head and to avoid jams.

Follow these steps to insert the paper:

Hold the paper roll in one hand and unroll the paper from the bottom side of the roll
Insert the paper into the slot located on the back side of the calculator
Press the paper advance button (marked [n]) until the paper is properly fed by the mechanism
Once the paper is well engaged, insert the roll into the paper holder provided for this purpose

After insertion, check that the paper advances correctly by pressing the advance button again. The paper should unroll smoothly and evenly. If the paper does not advance or jams, stop immediately and check that the initial edge has been properly prepared and that the roll is correctly positioned in the holder.

Question 10

Why does the OLIVETTI LOGOS 694ΑT calculator perform an automatic multiplication when entering an addition?

Accepted Answer

The OLIVETTI LOGOS 694ΑT calculator has a constant calculation function that allows for repeated multiplications or divisions with a stored value. If you notice that a multiplication occurs automatically when entering an addition, it is likely that a constant calculation mode has been accidentally activated or misinterpreted.

Probable cause: The constant calculation mode is intended to multiply or divide a number by a fixed value stored in memory. If this mode is active, entering a number and then pressing an operation key other than the standard addition may trigger a multiplication. Also, ensure you are using the correct keys: for a simple addition, you should use the [+]1 or [+]2 key depending on the chosen totalizer, not a special function key.

Procedure for using simple addition:

Enter the first amount to add
Press the [+]1 key (or [+]2 for the second totalizer)
Enter the next amount
Press [+]1 (or [+]2) again
Continue for all your additions
To obtain the result, press [T]1 or [T]2 (Total key)

If the problem persists: It is possible that a key is faulty or physically stuck, or that a memory function is programmed on your machine. Press the [C/CE] key twice to completely reset the calculator (this clears all contents, including totalizers and Grand total memory). Then test a simple addition to check that normal operation is restored. If addition still triggers a multiplication, consult a specialized calculator repair technician, as this may indicate a hardware malfunction or modified internal programming.

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