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Posted Wed Aug 24, 2016 5:02 AM
Posted Wed Aug 2, 2017 11:08 PM
Have you had any luck finding the solutions to your problems? I don't get up here much, so that is why I haven't responded prior to this.
If you have a volt-ohm meter, the 1st thing you want to check is the voltages. There are 4 different values to look for:
10V ( this is power to all custom chips, the last stage of the Oscillator and the RF modulator.) Ground to pin 40 of the custom address chip. (the middle one.)
5V any small chip, usually the highest number pin (I.E. pin 16 of a 16 pin chip.) to ground. 4.5 to 5.5V. Iv lower than 5V, you probably have a shorted part somewhere on the board
-5V This goes to the modulator and to pin #1 of the RAM chips, located under the keypad.
the last supply can be either 15V or 12 V. It goes to pin 8 of the RAM chips...only. To know which one you have, look in front of the silver colored, finned heat sink. If there is a jumper there, you have a 15V unit. If it is a 1/2W 47ohm (Violet, Yellow, Black, Gold) resister it is a 12V unit.
If any of these are more that 15% off, that is the area to check. You'll find the schematic on ballyalley.com in the service manual last 3 pages.
Posted Thu Aug 3, 2017 5:44 PM
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