bridge rectifier (?) question. its a simple one.

[rjd2]

so i BELIEVE i am looking at a bridge rectifier. its got 3 legs, one side flat, other rounded, model # says "K30A Y". almost doesnt matter-here's the question:

in the unit in question (yamaha cs-80), a WORKING voice card's bridge rectifier's voltage looks like this:

9
8
14

now on the voice im trying to FIX, the NON-WORKING one, it looks like this:
1
0
14

the question is this: does this guarantee fault in the bridge rectifier, or is it possible there is something UPSTREAM that could have failed that would cause the output voltages to look like such?

thanks as always guys!!!

[RodC]

A bridge rectifier with 3 pins? Sure its not a regulator or a transistor?

See if you can find a datasheet.

[rjd2]

sorry, its probably a transistor. my bad. here's a schematic of the board, it is the M-BOARD :

http://bermuda.ucd.ie/bridge/cs80/cs80_circ5.jpg


if i trace the +14v leg of the transistor(?), it comes directly from one of the incoming wires to the board. so if someone can confirm that a 3-legged beast of said description would have a 14v incoming leg, and supposed to be putting out 9v and 8v respectively on its other TWO legs, then i believe i can confirm a bad transistor.

[SeventhCircle]

I'd guess that beastie is a 2SK30A N-channel JFET, you can google a datasheet for the pinout and specs. Since your board appears to use them as switches, it wouldn't be unusual to see the gate voltage go below the source voltage (to ensure complete cutoff), which appears to be the case. I suspect the problem lies in the direction of whatever is tied to the gate (probably the pin that's measuring 0V), but I'm just guessing.

[brianroth]

sorry, its probably a transistor. my bad. here's a schematic of the board, it is the M-BOARD :

http://bermuda.ucd.ie/bridge/cs80/cs80_circ5.jpg


if i trace the +14v leg of the transistor(?), it comes directly from one of the incoming wires to the board. so if someone can confirm that a 3-legged beast of said description would have a 14v incoming leg, and supposed to be putting out 9v and 8v respectively on its other TWO legs, then i believe i can confirm a bad transistor.

Which part are you referring to on that schematic?

Bri

[rjd2]

thanks alot for the help guys.

so i popped out the VCO chip of a working voice card just to measure the card without the chip, and lo and behold, the voltage on those other 2 legs of this WHATEVER is being fed by the VCO chip. problem was upstream.

thanks much! problem solved.