Power Circoitry Checkoot

062, a and R129 minimum centered

25 volts

A) With power applied to board, both L.E.D.'s on boards should be lit, indicating presence of plus and minus 25v.

1 If not lit, check fuse(s) on board.

2 25 volts (plus or minus) must be present at U69 and U68 input pins.

a) If not, check U69 (or U68) and D1 (or D4) for shorts.

15 volts

A) 15 volts (plus or minus) must be present at U69 and U68 output pins.

1 If not check U69 (or U68), D1 (or D4) and D2 (or D3) for shorts.

2 Verify 25 volts (plus or minus) present at input pins of U69 (or U68).

+5 volts

A) Verify +5 volts (from main power supply) present at

+2.2 volts

A) Transistor Q1 and R6, R7 and R8 provide 2.2 volts to Q2 and Q18.

1 +2.2 volts should be present at emitter of Ql.

2 +5 volts should be present at collector of Ql.

0 0

Post a comment