| Manufacturer: | Victor |
| Model: | 19-1421 |
| Year: | 1973 |
| Form: | Desktop |
| Functions: | Basic four, user memory |
| Number of Digits: | 12 |
| Display Type: | PPX |
| Display: | Burroughs BR 13403 (Panaplex) | | Logic Technology: | LSI-2 |
| Diodes: | 39 |
| Transistors: | 17 |
| IC Complement: | Rockwell 10567 PD
Rockwell 10584 PB
Rockwell? 50210-49 (2)
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| Tech. Data Level: | 2 |
| Tech. Data Source: | RE |
| Tech. Data Pages: | 1 |
| Tech. Data: | Schematic (pdf) |
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Victor is the Victor Comptometer Corporation, a company with a long standing producing mechanical calculators for the business/accounting market.
This is one of their electronic models produced as the bottom dropped out of the mechanical market.
The Victor 1900 series followed shortly after the 1800 series.
The keyboard - a design shared with the 1800 series - is of high quality, built to withstand the heavy daily use of accounting departments,
with a low-wear contact arrangement and a double-action mechanical mechanism that controls and limits the forces seen at the contacts.
With that said, these keyboards do have a failure mode, see the associated note.
| Notes: |
The keyboard is a 'button-contact' style, the diagram to the right shows a cross-section view of the contact arrangement.
The actual electrical switch contacts are interleaved-finger traces on a printed circuit board.
Sitting above the contacts is a conductive rubber button,
with a small amount of clearance provided by a thin membrane over the PCB, with holes in it where the contacts and buttons are.
The plunger from the key mechanism pushes the conductive rubber button onto the interleaved contact fingers, connecting them together and thus closing the switch.
The double-action mechanical mechanism limits the amount of force the plunger applies to the button.
Normal ON resistance for the contacts is 100 ~ 400 ohms.
Apparently with age or inappropriate force, the button can deform enough to present as stuck ON.
See log entry below for a resolution.
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Internal view.
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The logic board and electrical half of the keyboard with its conductive rubber buttons.
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The keyboard mechanical mechanisms provide a double action to limit the forces on the electrical contacts as well as a soft indent in travel.
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- Unit Log -
| Serial Number: | 4666-006 |
| Year of Manufacture: | 1973 (Integrated circuits stamped with 7321 and 7322) |
| Date of Receipt: | Jan 1990 |
| Source: | Mom. |
| State upon Receipt: | Good physical condition. Fully functional. |
| Current State: | Fully functional (Jan 1990). |
| Date: | Sep 1999 |
| Procedure: | Cleaned extensively, including rebuilding of keyboard with new rubber bumpers. |
| Date: | Oct 1999 |
| Procedure: | Original power connector replaced with IEC standard. Power lamp replaced. |
| Date: | 2021 Feb |
| Symptoms: | After being opened for pictures and some wiping of the keyboard button pads,
the unit no longer responds upon power-up.
The display presents the normal power-on zero, but all keypresses are ineffective. |
| Analysis: | Scoping indicates that several key contacts (CA,PLUS,MULTIPLY) are stuck 'ON', with contact resistance around 200-300 ohms.
The logic is ignoring any more key activity until the ON keys are 'released'. |
| Procedure: | Sticky tape used to 'pull up' the rubber buttons.
This was effective temporarily, but the CA & PLUS keys later reverted to the ON state.
(Stickier tape might be more successful to lift the button more without requiring as much downward force to get adhesion.)
Exacto knife used between the clearance membrane and the adhesive to gently half-lift the rubber buttons,
thin screwdriver then used to lightly push up around the middle of the button from the inside. |
