Mattel ECS Troubleshooting
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Fault-finding for the Mattel ECS (Entertainment Computer System). Mattel published no service manual or schematic for it; the checks below come from the owner's guide and its errata sheet, from programmers' notes on the hardware, and from Avon Fox's photographs of an adaptor taken apart.[1][2][3][4] Faults in the Master Component itself are covered on Intellivision Troubleshooting Guide and Intellivision II Troubleshooting Guide. Routine care is on Mattel ECS Maintenance.
What a working ECS does
[edit | edit source]- With a cartridge in the adaptor's port, both transformers plugged in, the television on and the Master Component switched on and reset, the screen shows a title with "ECS" and copyright information.[1][5]
- Pressing the disc on either hand controller brings up the menu: 1 for BASIC, 2 for the cartridge, 3 for music.[1][6]
- Choosing BASIC (1, then ENTER) gives a blank screen with a square cursor in the upper left corner.[1]
- Mattel's balance test plays two alternating tones, one on channel 1 and one on channel 4. Channels 0-2 are on one sound chip and 3-5 on the other, so the test exercises both.[1][7]
Things that are not faults
[edit | edit source]| What you see or hear | Why | Source |
|---|---|---|
| Nothing at all on the television | No cartridge in the adaptor's own port. Any standard cartridge will do | [5] |
| Loud hiss from the television at switch-off | The Master Component was switched off before the television | [1] |
| A tone keeps sounding after ESC stops the balance test | ESC stops the program, not the sound. Type CALL HUSH and press RTN | [5] |
| A typed line turns grey when RTN is pressed | BASIC did not understand the line, or there was not enough memory for it | [8] |
| A short whistle | An attempt to divide by zero; it is noted with a whistle | [8][9] |
| A long whistle when a moving object is displayed | Not enough memory for the GRAB routine | [8] |
| Typing stops at the end of the second screen line | A program line holds at most 39 characters; the screen is 20 characters wide | [10] |
| The program has gone | RAM is erased when the Master Component is switched off or RESET is pressed | [11] |
| CTL does nothing | CTL is not used by the built-in BASIC | [12] |
| Wrong characters, or none, with several keys held | The keyboard matrix has no diodes; three keys on the corners of a rectangle read as a fourth, and keys in the same row or column can cancel each other | [3] |
Picture and start-up faults
[edit | edit source]| Symptom | Probable cause | Action |
|---|---|---|
| Nothing on the screen with the ECS fitted | No cartridge in the adaptor's port | Fit a known-good cartridge in the adaptor[5] |
| Still nothing, with a cartridge fitted | The adaptor is not fully home in the Master Component, or its edge fingers or the cartridge's contacts are dirty | Push the adaptor in as far as it will go. Clean the gold contacts with alcohol on a lint-free swab, not an eraser[1][13] |
| Still nothing | The adaptor has no power | Check that its own transformer is plugged in, that it is the one marked for the Computer Adapter, and that it gives an AC voltage at the pin-plug; the US transformer is rated 10.0 V AC at 1.0 A[1][14] |
| The cartridge works in the Master Component on its own, but not through the ECS | Fault in the adaptor | See the power checks below; inspect the adaptor's cartridge port for bent or dirty contacts |
| No picture without the ECS either | Master Component fault | See Intellivision Troubleshooting Guide or Intellivision II Troubleshooting Guide |
Power checks inside the adaptor
[edit | edit source]The only power circuit documented for the ECS is what Avon Fox's photograph of one 240-volt board shows: a TO-3 regulator marked 309K on a finned heatsink, a TIP32 transistor, four diodes marked D1 to D4 and a large axial electrolytic capacitor near the power jack.[4] Check your own board against it before relying on the figures below.
The 309K is a 5-volt, 1-amp regulator. In the TO-3 case it has two pins, input and output, and the case is the ground connection.[15]
- With the Master Component off and the ECS transformer plugged in, measure the regulator's input pin to the case. National's specification holds the output in tolerance for inputs from 7.4 V to 25 V.[15]
- Measure the output pin to the case. Expect 4.75 V to 5.25 V across that input range and load.[15]
- If the input is low or missing, check the transformer, the pin-plug and POWER jack, the four diodes and the large electrolytic. If the input is good and the output is low, check for a short on the 5 V side before condemning the regulator. The 309K has current limiting and thermal shutdown, so a short on the 5 V side normally pulls its output down without destroying it.[15]
- Replace a failed reservoir capacitor with the same capacitance and the same or a higher voltage rating; see Mattel ECS Capacitor Replacement Guide.
Keyboard faults
[edit | edit source]The keyboard is a passive 48-position matrix: a board of gold pads under rubber domes, wired straight to its cable, with no components of its own. The adaptor scans it through the two I/O ports of the AY-3-8917 sound chip, with 16 series resistors between the chip's ports and the keyboard connections.[3][16]
| Symptom | Probable cause | Action |
|---|---|---|
| No keys work | Cable not in both connectors under the hinged cover, or a broken cable | Reseat the plug in both connectors; check the cable where it leaves the keyboard case and at the solder pads[1][16] |
| A single key fails | Dirt on that key's pad or dome | Clean the pad and dome with isopropyl alcohol; see Maintenance |
| A whole row or column of keys fails | One wire of the cable broken, or one of the series resistors on the adaptor board open | Check the cable for continuity, then the resistors; the matrix layout is on the Intellivision Wiki page[3] |
| Keyboard dead, with the cable and keyboard board checked good | The keyboard is scanned through the AY-3-8917's I/O ports | Check the 5 V supply on the adaptor board and the series resistors, then suspect the AY-3-8917[3] |
The MUSIC option on the main menu is a quick test of the whole keyboard: with the Computer Keyboard plugged in, each key plays a different note, and the notes appear on a musical staff on the screen.[6]
Sound faults
[edit | edit source]- Run the balance test from Maintenance. If one of the two tones is missing, one of the two sound chips is not being heard.[1][7]
- If both tones play but at very different levels, turn the balance control under the hinged cover until they match.[1]
- The ECS's sound chip is a General Instrument AY-3-8917 at addresses $00F0-$00FF.[2][4]
Cassette faults
[edit | edit source]Connect the recorder with three cables: EAR on the recorder to IN FROM TAPE, MIC to OUT TO TAPE, and REM to REMOTE. The first two are mini-plug cables; the remote cable has sub-mini-plugs.[1] The commands are CSAV to save, CLOD to load and CVRF to verify, each followed by a program name of up to four characters.[17]
| Symptom | Probable cause | Action |
|---|---|---|
| The screen shows SET and nothing happens | The ECS is waiting | Position the tape, press any key or the disc (the screen shows GO), then press PLAY, or PLAY and RECORD, on the recorder[17] |
| No relay click when CSAV or CLOD starts | The cassette motor relay is not being switched | The relay in the adaptor clicks during CSAV and CLOD. With no click, check the relay and the REMOTE cable[2] |
| LOAD keeps searching | The name does not match, or the tape started past the program | Type exactly the name used to save; rewind and try again[17] |
| VERF name and message turn grey | The data on tape does not match memory | Save again; Mattel advises saving each program two or three times[17] |
| Saves or loads fail with any tape | Recorder below specification, or lost data on the leader | The recorder needs at least 500 Hz to 5 kHz ±3 dB, 3 V peak to peak output at 2400 Hz and 4800 Hz into 100 ohms, and 1⅞ in/s ±3 %. Wind past the plastic leader; use C30 or C60 tapes[5][17] |
Recorders Mattel listed as suitable include the Aquarius Data Recorder, Toshiba KT-P22 and KT 1500, and Realistic CTR-57 and CTR-60.[5]
Printer faults
[edit | edit source]The Aquarius printer plugs into the AUX jack beside the cassette jacks, using the cable supplied with it. To test it, load or type the balance program, then type D=-4 and press RTN, then CALL OUTP and press RTN. The program listing should print. For any other printer, Mattel's guide only told owners to call its service line to ask.[1]
Final notes
[edit | edit source]- No schematic, parts list or test procedure for the ECS has been published, and Mattel's own guide covers only setup and use.[1]
- The board described here is from one 240-volt adaptor. Photograph your own board before working on it.
- Faults that are present with the ECS removed belong to the Master Component.
Related pages
[edit | edit source]- Mattel ECS
- Mattel ECS Maintenance
- Mattel ECS Capacitor Replacement Guide
- Mattel ECS Documentation
- Intellivision Troubleshooting Guide
- Intellivision II Troubleshooting 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 1.10 1.11 1.12 1.13 Mattel Electronics, Computer Module Owner's Guide (1983, 4487-6002), File:Intellivision Computer Module Owner's Guide (Mattel, 1983).pdf. PDF pp. 9-11: the adaptor goes into the Master Component's cartridge port, pushed in as far as it will go; the keyboard plugs into the two connectors under the hinged cover; "Use the transformer marked 'For use with Intellivision Computer Adapter only'"; start-up order; the "ECS" title screen; the disc brings up the menu; choose BASIC with 1 and ENTER; a blank screen with a square in the upper left corner; the balance test program (C=1, then C=4) and "two alternating tones"; the balance control. PDF p. 12: EAR to IN FROM TAPE, MIC to OUT TO TAPE, REM to REMOTE; two mini-plug cables and one sub-mini-plug cable. PDF p. 13: the Aquarius printer and its cable on the AUX jack, next to the cassette jacks; the test "D=-4 ... CALL OUTP"; "Other printers may be compatible ... call one of the Service/Information numbers"; switching the Master Component off before the television gives "a loud hissing noise ... You haven't broken anything". PDF p. 83: no published service information beyond cleaning; "Never open the chassis".
- ↑ 2.0 2.1 2.2 Joe Zbiciak, "Entertainment Computer System" (revision of 11 December 2000, retrieved 2026-10-19): a second PSG at $00F0-$00FF; the cassette/printer UART at $E0-$E3; the cassette motor relay, controlled by bit 4 of $E2, "makes a 'click' when doing a CSAV/CLOD".
- ↑ 3.0 3.1 3.2 3.3 3.4 Intellivision Wiki, "Entertainment Computer System" (last edited 2 April 2012, retrieved 2026-10-19): the AY-3-8917's two I/O ports scan the keyboards; the ECS has current-limiting resistors in series with both ports, 16 in all; the alphanumeric keyboard is a 48-position matrix with no diodes, so pressing keys on three corners of a rectangle causes ghosting, and keys sharing a column or row can mask each other; matrix table of rows and columns.
- ↑ 4.0 4.1 4.2 Avon Fox, the-liberator.net (as above), photograph 014, hosted as File:Intellivision ECS Computer Adaptor board, 240 V version (Avon Fox).jpg: the main board of a 240-volt adaptor, with the TO-3 regulator marked 309K, the TIP32, diodes D1-D4, the large axial electrolytic under a cable tie, and the GI AY-3-8917.
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 Mattel Electronics, errata sheet No. 4187-0170, bound with the guide, File:Intellivision Computer Module Owner's Guide (Mattel, 1983).pdf, PDF pp. 90-92: to stop the sound of the balance test, type CALL HUSH and press RTN; a cartridge must be in the adaptor's port ("If a cartridge isn't plugged in, nothing will appear on the TV screen"); cassette recorder specifications; recommended recorders (Aquarius Data Recorder, Toshiba KT-P22, Toshiba KT 1500, Realistic CTR-57, Realistic CTR-60 and others).
- ↑ 7.0 7.1 Mattel Electronics, Computer Module Owner's Guide (as above), PDF p. 41 (printed p. 44): the Master Component and the Computer Adaptor each contain a sound chip with three channels; "Channels 0-2 are on chip 1 and channels 3-5 are on chip 2."
- ↑ 8.0 8.1 8.2 Mattel Electronics, Computer Module Owner's Guide (as above), PDF pp. 76-77 (Appendix C, Errors): a statement or command not understood is re-coloured grey; a line entered with insufficient memory is displayed in grey; divide by zero gives a short whistle; displaying a moving object with GRAB without enough memory gives a long whistle.
- ↑ Errata sheet (as above), PDF p. 92, for printed p. 85: "Attempts to divide by zero are not really refused, but rather NOTED with a short whistle."
- ↑ Mattel Electronics, Computer Module Owner's Guide (as above), PDF pp. 20-21: twenty characters across the screen; thirty-nine characters make one line; after thirty-nine the computer "will refuse to print any more characters" until RTN is pressed.
- ↑ Mattel Electronics, Computer Module Owner's Guide (as above), PDF p. 76: everything stored in RAM is erased when the Master Component is turned off or RESET is pressed.
- ↑ Mattel Electronics, Computer Module Owner's Guide (as above), PDF p. 19: CTL "not used with built-in BASIC".
- ↑ INTV Funhouse, "Intellivision FAQ: Section 7", section 7.2 (retrieved 2026-10-19): a black screen can come from a cartridge inserted not far enough or too far, or from dirty contacts; clean with a cotton swab and denatured alcohol; not a pencil eraser.
- ↑ INTV Funhouse, "Intellivision FAQ: Section 3", section 3.9 (retrieved 2026-10-19): ECS power supply "Output: 10.0 VAC, 1.0 A".
- ↑ 15.0 15.1 15.2 15.3 National Semiconductor, LM109/LM309 5-Volt Regulator data sheet (DS007138, April 1998), ti.com (retrieved 2026-10-19). P. 1: complete 5 V regulators; output current over 1 A in the TO-3 package; current limiting and thermal shutdown. P. 2: LM309 output 4.8-5.2 V at 25 °C, and 4.75-5.25 V for 7.40 V ≤ VIN ≤ 25 V over the load range; maximum input 35 V; LM309K connection diagram: input and output pins, ground on the case.
- ↑ 16.0 16.1 Avon Fox, "Intellivision Entertainment Computer System (ECS) Rev C", the-liberator.net (retrieved 2026-10-19), photographs 020-023: the keyboard opened, with its rubber-dome sheet and a circuit board carrying only contact pads, the cable soldered at one corner.
- ↑ 17.0 17.1 17.2 17.3 17.4 Mattel Electronics, Computer Module Owner's Guide (as above), PDF pp. 73-74 (Appendix B): CSAV, CLOD and CVRF with a name of up to four characters; SET, then GO after a key or the disc is pressed; PLAY to load or verify, PLAY and RECORD to save; LOAD searches until the names match; a missed starting point means rewinding; VERF message and name turn grey when the data does not match; C30 or C60 tapes; move past the plastic leader; save two or three times.