Carte de diagnostique 781220

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Tests des puces RAM

Si une erreur liée à la mémoire est détectée lors du test au lancement de la cartouche (20 secondes), l'écran se mettra à flasher (noir et blanc) avec une pause entre chaque série. Le nombre de flash indique quelle puce est non fonctionnelle.

Le tableau ci-dessous indique pour la révision de la carte mère, quelle puce est défectueuse pour quel nombre de flash.

Flash	C64 Rev A/B	C64 Rev B-3	C64 Rev E	C128	C128D	Bit de données
Nb RAMs	8	2	2	16	4	-
1	U12	U9	U11	U45 / U53	U39 / U41	7
2	U24	U9	U11	U44 / U52	U39 / U41	6
3	U11	U9	U11	U43 / U51	U39 / U41	5
4	U23	U9	U11	U42 / U50	U39 / U41	4
5	U10	U10	U10	U41 / U49	U38 / U40	3
6	U22	U10	U10	U40 / U48	U38 / U40	2
7	U9	U10	U10	U39 / U47	U38 / U40	1
8	U21	U10	U10	U38 / U46	U38 / U40	0

Si plus d'une puce est défectueuse, le test exécutera la séquence pour la 1er problème détecté. Une fois la puce remplacée, la séquence sera celle de la prochaine puce défectueuse. Et cela continuera jusqu'à temps que toutes les puces défectueuses soient remplacées.

Ce test initial fonctionne même si la majorité des puces sont enlevées de la carte mère à l'exception du MPU, PLA et VIC. Ceci permet d’éliminer ces puces non obligatoires comme sources du problème.

If the Dead Test executes a Flash Code Sequence and RAM replacement or Socketed IC Removal does not correct the problem, use a scope to verify the defective Data Line. Once this is accomplished it may be necessary to begin clipping IC pins associated with the Data Line.

1. Clip the pin as close to the PCB as possible and lift the pin away from the PCB
2. ReTest System with the Dead Test
3. If result is the same, resolder the pin and continue to the next Associated IC
4. Continue with these steps until the Dead Test executes properly
5. If the Dead Test operates properly, Replace the IC associated with the clipped pin and retest

Test de la page RAM zéro

Zero Page Memory resides at Locations $0000 - $00FF. Two of these locations, $0000 and $0001, are reserved for the MPU I/O Port, these two locations cannot be tested.

The Zero Page Test writes data from the data table into locations $0003 - $00FF.

This data is then read and compared to Stored Data.

• IF DATA READ = DATA WRITTEN, ZERO PAGE RAM IS [OK]
• IF DATA READ <> DATA WRITTEN, ZERO PAGE RAM IS [BAD]

If a failure occurs during the Zero Page Test, any indicated RAM IC must be replaced.

If this does not correct the problem, or if more than two RAM ICs are displayed defective, Refer to the RAM Sections of the appropriate Diagnostic and Troubleshooting Manuals.

Test de la page RAM de la pile

The Stack Page resides at Memory Locations $0100 - $01FF.

The Stack Page Test writes data from the Data Table into each of these locations. The data is then read and compared to Stored Data.

• IF DATA READ = DATA WRITTEN, STACK PAGE RAM IS [OK]
• IF DATA READ <> DATA WRITTEN, STACK PAGE RAM IS [BAD]

If a failure occurs during the Stack Page Test, any indicated RAM IC must be replaced. If this does not correct the problem, or if more than two RAM ICs are displayed defective, Refer to the RAM Sections of the appropriate Diagnostic and Troubleshooting Manuals.

Test de la RAM graphique

The Screen RAM resides at Memory Locations $0400 - $07FF. The Screen RAM Test writes data from the Data Table into each of these locations. After a short delay, to allow Refresh, the data is read and compared to the written data.

• IF DATA READ = DATA WRITTENf SCREEN RAM IS [OK]
• IF DATA READ <> DATA WRITTEN, SCREEN RAM IS [BAD]

If a failure occurs during the Screen RAM Test, any indicated RAM IC must be replaced.

If this does not correct the problem, or if more than two RAM ICs are displayed defective, Refer to the RAM Sections of the appropriate Diagnostic and Troubleshooting Manuals.

Test de la RAM couleur

The Color RAM resides at Memory Locations $D800 - $DC00.

The C64 Color RAM uses the Lower Four (4) Bits to display any color, therefor a revised version of the Data Table is used for Color RAM Testing. This revised Data Table uses the same type of Data Patterns but only with the Lower Four (4) Bits.

The Color RAM Test writes data from the Data Table into each of these locations. After a short delay, to allow Refresh, the data is read and compared to written data.

• IF DATA READ = DATA WRITTEN, COLOR RAM IS [OK]
• IF DATA READ <> DATA WRITTEN, COLOR RAM IS [BAD]

If a failure occurs during the Color RAM Test, any indicated RAM IC must be replaced. If this does not correct the problem, or if more than two RAM ICs are displayed defective, Refer to the RAM Sections of the appropriate Diagnostic and Troubleshooting Manuals.

Test de la RAM

Because of the configuration of the Dead Test Diagnostic Cartridge only RAM Locations $0800 - $1000 can be tested.

The RAM Test writes data from the Data Table into each of these locations.

• As the data is written to these locations the Character Set is replaced and should slowly disappear from the screen.
• After approximently 30 Seconds, when the RAM Test is complete, the Screen should Reappear.

After a short delay to allow Refresh, the data is read and compared to the Data Table.

• IP DATA READ = DATA WRITTEN, RAM IS [OK]
• IP DATA READ <> DATA WRITTEN, RAM IS [BAD]

If a failure occurs during the RAM Test, any indicated RAM IC must be replaced.

Test du son

When the RAM Test is complete and the Dead Test Screen is Redisplayed, the Sound Test is executed.

The Sound Test is an Audible Test Only and no [OK] or [BAD] message will be displayed. The Sound Test should produce Three (3) Distinctive Voices at Three (3) Volume Levels followed by Three (3) Bursts of Noise.

If any of the Voices, Volume Levels or Noise Bursts are missing, a Defective SID IC is normally indicated.

If replacement of the SID IC does not correct the problem, troubleshooting of the Audio Output Circuitry is necessary.