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Intellivision Keyboard Component Troubleshooting Guide

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Intellivision Keyboard Component test set-up figures (Mattel)
Mattel's test set-ups from the 1980 service manual: the television (Figure 1), the Master Component on its own (Figure 2) and the Keyboard Component with its test cartridges, demonstration cassette and microphone (Figure 3).

Mattel's 1980 Keyboard Component Service Manual diagnoses the Intellivision Keyboard Component (model 1149) at module level: a power test with voltage limits, a logic board self-test, a keyboard test and a tape test, each ending in the replacement of a board or assembly.[1] Schematics for the production boards have not been found. Disassembly is on Intellivision Keyboard Component General Maintenance; faults in the Master Component itself are on the Intellivision Troubleshooting Guide.

Owner's checks

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The Owner's Book gives a short checklist before anything is opened:[2]

Mattel's owner checklist
Symptom Mattel's checks
Screen blank at power-up Check the television is plugged in. Connect the aerial straight to the television, bypassing the antenna switch box; if there is still no picture, the fault is in the television.
Snow on the screen Switch the Master Component off and on and press RESET. Check that the television is on the same channel as the Master Component (the channel switch is under the Master Component, so it has to be unscrewed from the Keyboard Component). Check the switch box with ordinary television reception. Check the switch box cable and cable extender in the Keyboard Component, and the power cord and flat ribbon cable between the two units.
Jumpy picture Push the switch box cable and cable extender fully into the back of the Keyboard Component.
"BAD TAPE" on the screen during cassette play The computer has found an error on the tape. It corrects the error if it can; if not, it ejects the tape.
Tape breaks or tangles in the mechanism Stop the tape with CTRL-C twice and use the emergency eject (see General Maintenance).

If the connections are all good and the snow remains, take the Master Component out, plug its power cord straight into the wall, connect its switch box cable directly and try a game cartridge in it. If it works alone, the fault is in the Keyboard Component; if it does not, the fault is in the Master Component.[2]

Test equipment

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Mattel's service procedure uses a high-impedance multimeter (20,000 Ω/V, 1% accuracy), a Phillips screwdriver and a 1/4-inch nut driver, the Master Component test cartridge, a video test cartridge (part 1718), a demonstration cassette, the Keyboard Component Test Cartridge (part 3399) and the Keyboard Test Cassette (part 3396).[3] Set the television's automatic colour controls to manual before testing.[4]

Without Mattel's test cartridge, Frank Palazzolo's KCMon is a cartridge image that loads a 6502 monitor program into the Keyboard Component through the Intellivision cartridge slot. He wrote it for reverse-engineering the unit.[5]

Check the television and Master Component first

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Mattel's manual does not start on the Keyboard Component until the television and Master Component are known to be good.[4]

  1. Check the television on broadcast signals through the antenna switch unit, and bypass the switch unit if there is no signal.
  2. Connect the Master Component and Keyboard Component together. Put the Master Component test cartridge in the Keyboard Component's cartridge port, switch on, press RESET, type C and press RETURN to start the cartridge, and run the Master Component diagnostics.
  3. If the Master Component fails, take it out of the Keyboard Component, test and repair it on its own (see the Intellivision Troubleshooting Guide), then try it in the Keyboard Component again.
  4. If a Master Component known to be good does not work in the Keyboard Component, go on to the Keyboard Component tests.[6]

Power test

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Intellivision Keyboard Component Figure D board removal (Mattel)
Figure D of the service manual: the power supply board (top right of the drawing) and the logic board in the lower housing.

Put the Keyboard Component Test Cartridge in the right-hand receptacle at the rear of the Keyboard Component, set the switch unit to GAME, switch the Master Component on and press RESET. If the screen shows "INTELLIVISION Intelligent Television", go on to the logic board test. If it stays blank:[4][7]

  1. Switch off and open the Keyboard Component. Check fuse F1 on the switching power supply and replace it if it has blown (3AG, 5 A, 250 V, normal blow).[8]
  2. Switch on and measure the DC outputs against the check limits below. Adjust +5 V and +12 V to within the adjustment limits; −5 V has no adjustment.
  3. If the voltages are within limits but the screen stays blank, replace the logic board. If adjusting the voltages brings up the title, go on to the logic board test.
  4. If there are no DC voltages or they cannot be adjusted into limits, switch off and disconnect the cable between the logic board and the tape control assembly (at J1 on the tape control board) and the cable between the power supply and the tape control assembly (at J2). Switch on and check the voltages again.
  5. If the voltages are now good, the fault is in the tape deck or the tape control assembly. Reconnect the power cable at J2, disconnect the two flat ribbon cables between the cassette drive and the tape control board, and measure again. Good voltages now point to the tape deck; bad voltages to the tape control board.
  6. If the voltages are still bad with the tape control assembly disconnected, measure the AC from the transformer at the power supply board's receptacle J1: it should be 17–23 V AC. If it is, the power supply board is faulty. After replacing it, check and adjust the DC voltages again; if they still cannot be brought into limits, the logic board is faulty.
  7. If the AC at J1 is outside 17–23 V, measure the mains at the transformer's female receptacle: it should be 105–125 V AC. With good mains there and low AC at J1, Mattel replaces both the power supply board and the transformer.[7]
DC voltage limits (service manual tables 4.1, 4.2, 5.1 and 5.2)
Rail Check limits Adjust to
+5 V +4.85 to +5.15 V Up to +5.05 V (lower limit printed as 4.45 V)
+12 V +11.64 to +12.36 V +11.88 to +12.12 V
−5 V −4.85 to −5.00 V No adjustment

The lower adjustment limit for +5 V is printed as 4.45 V in both of Mattel's adjustment tables, which is below the 4.85 V lower check limit in the same tables.[7]

The service manual does not say where to measure. Mattel's 1979 schematic of an earlier power supply has an 8-pin logic board connector J2 (+16 V on pin 1, ground on pins 2 and 3, +12 V on pin 4, +5 V on pins 5 and 6, −5 V on pin 7, and a "turn on control (+5V)" input on pin 8) and a 6-pin tape control connector J3 (+5 V for an inductive load on pin 1, a separate +16 V supply on pin 2, ground on pins 3 and 4, +12 V on pin 5 and +5 V on pin 6).[9] Mattel's 1982 drawing list gives the production board an 8-conductor power ribbon to the logic board and a 6-conductor ribbon to the tape control, but the production board's pin assignments have not been found.[10] Mattel's isolation steps disconnect the tape control assembly but never separate the power supply from the logic board.[7]

Logic board test

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The logic board test runs itself at power-up, though it may need RESET on the Master Component.[1]

  1. Type I and press RETURN. The last command on the screen should be "TEST DIAGNOSTICS". If it is not, reseat the test cartridge; if it still does not appear, replace the logic board.
  2. Type TEST and press RETURN to start the automatic tests. Do not touch the keyboard until the screen asks you to: a key pressed during the test can produce the wrong diagnostic message.
  3. The screen shows "EXECUTING SELF TEST – PLEASE STANDBY", then "CPU1-UP", "CPU2-UP" and "CHECKING LOGIC BOARD". Each circuit is added to the list as it is tested, with an asterisk against the one under test and PASS when it passes (for example "HR GRAPHICS RAM – PASS", "KEYBOARD I/O PORT – PASS").
  4. A failed circuit shows FAIL, with the corrective action in a blue box at the bottom of the screen, such as "ACTION > REPLACE LOGIC BOARD". Carry out the actions in the order given and start again from power-up.
  5. When the tests are complete the screen shows "SELF TEST COMPLETE – PLEASE STAND BY", then a menu: 1 for the keyboard test, 2 for the tape test.[1]

Keyboard test

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Press 1 at the test menu. The screen shows a picture of the keyboard, and each character turns into a solid block when its key is pressed; the space bar appears at the top left. Mattel suggests running a fingernail along each row so that every key is pressed in turn. Press CLEAR SCREEN twice to return to the menu. Characters that do not block out mean a bad keyboard: replace the keyboard assembly and test again, and if the test still fails, replace the logic board.[11]

Tape test

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Press 2 at the test menu. The screen shows "PROCEED WITH DRIVE MAINTENANCE"; the drive ejects and then goes into play.[12]

  1. If the eject fails, replace the tape deck assembly, then the tape controller, then the logic board, rerunning the whole test from power-up after each.
  2. With the drive in play and the cassette holder raised, clean the heads, capstan and pinch roller (see General Maintenance). Check that the heads move forward into the playback position and that the reel drive shaft turns.
  3. Press CLEAR SCREEN twice to start the minimum tape test. Insert the demonstration cassette and close the housing door by hand. The test exercises every tape function, including the pre-recorded and home-recorded digital tracks.
  4. After the minimum tape test passes, the home audio test starts. Plug the microphone into the microphone jack. A menu shows which letter key drives each tape mode (E for eject, for example), so each mode and the home-recorded audio tracks can be checked by hand.
  5. If the drive fails in any mode, replace the tape deck assembly, then the tape controller, then the logic board.
  6. After repairs, assemble the unit, insert the cassette, type 7 and press RETURN to run the final test of all functions.[12]

Known weak points

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Mattel's own records point at the tape drive. In a 1981 life test, 31.25% of units had failed by 100 hours, all with tape stalls or torque adjustment faults. The repaired units failed again, mostly with tape stalls, along with a unit that would not load the "M" tape and a failure recorded as "CPU-2"; at 500 hours 31.25% failed with tape stalls.[13] A February 1982 review listed tape deck reliability, burn-in yields and compatibility between the Master Component and the keyboard among the open production problems.[14] Mattel's drawing list names a clutch belt and a flywheel belt in the tape deck, but no belt sizes or adjustment figures for the drive have been found.[10]

The 1981 parts list release made a new logic board, "Computer III", the board for future production in place of "Computer II".[15] When swapping modules between units, check which logic board each unit has.

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References

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  1. ↑ 1.0 1.1 1.2 Mattel Electronics, Keyboard Component Service Manual (1980), pp. 9–10 and note (1) on p. 9-A: logic board self-test. File:Mattel Intellivision Keyboard Component Service Manual (1980).pdf.
  2. ↑ 2.0 2.1 Mattel Electronics, Keyboard Component Owner's Book, pp. 26–27, "Computer in distress". File:Mattel Intellivision Keyboard Component Owner's Book.pdf.
  3. ↑ Mattel Electronics, Keyboard Component Service Manual (1980), p. 1, "Tools and Equipment Needed". File:Mattel Intellivision Keyboard Component Service Manual (1980).pdf.
  4. ↑ 4.0 4.1 4.2 Mattel Electronics, Keyboard Component Service Manual (1980), p. 5, section III set-up and power test: Master Component and television to be verified first, automatic colour circuits to manual, test cartridge in the right-hand rear receptacle. File:Mattel Intellivision Keyboard Component Service Manual (1980).pdf.
  5. ↑ Frank Palazzolo, "Mattel Intellivision Keyboard Component", MAMEDEV forum, 3 November 2016 (retrieved 2026-10-19): KCMon, "a cartridge image which loads a 6502 monitor program into the actual hardware via the Intellivision cartridge slot".
  6. ↑ Mattel Electronics, Keyboard Component Service Manual (1980), pp. 3–4, sections I and II. File:Mattel Intellivision Keyboard Component Service Manual (1980).pdf.
  7. ↑ 7.0 7.1 7.2 7.3 Mattel Electronics, Keyboard Component Service Manual (1980), pp. 6–9: fuse F1, tables 4.1 and 4.2, isolation of the tape control and tape deck, 17–23 V AC at J1, tables 5.1 and 5.2, 105–125 V AC at the transformer receptacle. File:Mattel Intellivision Keyboard Component Service Manual (1980).pdf.
  8. ↑ Mattel Electronics, Keyboard Component Service Manual (1980), p. 2: fuse, 3AG, normal, 5 A, 250 V, part 0089-0803. File:Mattel Intellivision Keyboard Component Service Manual (1980).pdf.
  9. ↑ Mattel Electronics, drawing 1149-9099, power supply schematic, 1979: connectors J2 (logic board) and J3 (tape control) with their pin functions and output ratings. File:Mattel Intellivision Keyboard Component Power Supply Schematic 1149-9099 (1979).pdf.
  10. ↑ 10.0 10.1 John H. Lishman, "Keyboard Component Drawing List" 1149-5829A, 1 June 1982. In Keyboard Component Plans (1982), PDF pp. 15–17. File:Mattel Intellivision Keyboard Component Plans (1982).pdf.
  11. ↑ Mattel Electronics, Keyboard Component Service Manual (1980), p. 11, "Typewriter keys – do they all work?". File:Mattel Intellivision Keyboard Component Service Manual (1980).pdf.
  12. ↑ 12.0 12.1 Mattel Electronics, Keyboard Component Service Manual (1980), pp. 12–13, tape test, drive maintenance, minimum tape test, home audio test and final test. File:Mattel Intellivision Keyboard Component Service Manual (1980).pdf.
  13. ↑ D. Bowen, "Intellivision Keyboard Quality", 23 November 1981, page 4, "Life test results to date". In Keyboard Component Plans (1982), PDF p. 4. File:Mattel Intellivision Keyboard Component Plans (1982).pdf.
  14. ↑ Mattel Electronics, "Reduced Cost Keyboard: Evolution of Present Plan" (February 1982). In Keyboard Component Plans (1982), PDF p. 18. File:Mattel Intellivision Keyboard Component Plans (1982).pdf.
  15. ↑ Mattel Electronics, engineering decision memo 1149-269, 25 June 1981: 1149-7809 (Computer III) supersedes 1149-9809 (Computer II) for future production. Internet Archive item 19810625KeyboardComponent.


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