Texas Instruments TI-99/4A Repair (1 of 6)

Defect:

• Black Screen and deafening sound in background.

Replaced parts:

• 1 x TMS 4732/2532 ROM (U610)

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 Texas Instruments TI-99/4A Repair (2 of 6)

Defect:

• Black Screen and deafening sound in background.

Replaced parts:

• 1 x MCM 6810P (128 x 8-Bit Random-Access Memory TTL/DTL) (U608)

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Texas Instruments TI-99/4A Repair (3 of 6)

Defect:

• Black Screen and deafening sound in background.

Replaced parts:

• 1 x 74LS138 (U504)
• 1 x 74LS138 (U505)

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Texas Instruments TI-99/4A Repair (4 of 6)

Defect:

• Black Screen and deafening sound in background.

Replaced parts:

• 1 x TMS 9900NL CPU (U600)

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Texas Instruments TI-99/4A Repair (5 of 6)

Defect:

• Garbage Boot Screen.

Replaced parts:

• 1 x TMS4116-15 RAM (U106)

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Texas Instruments TI-99/4A Repair (6 of 6)

Defect:

• Various problems with audio playback.

Replaced parts:

• 1 x SN76494N – Digital Complex Sound Generator (U511)

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