Re: more on ACT CR230 repeater failure

[ddl@danlan.*com (Dan Lanciani)]

In article <3l2mk1pu64s2dddm26l25ouq1daen08o4u@xxxxxxx>, MFHult@xxxxxxxxxxxxxxxxxxxxx (Marc F Hult) writes:
| On 10 Oct 2005 22:56:52 GMT, ddl@danlan.*com (Dan Lanciani) wrote in message
| <1331627@xxxxxxxxxxxxxxxxxxx>:
|
| >On closer examination it turns out that both pads of the zener had
| >separated from the board (a good trick considering that one of them is part
| >of a little ground plane).  The trace that supplies power to the drivers is
| >routed through the zener's pad, so it's difficult to determine what
| >happened.  Depending on the order of pad failure the drivers could have
| >seen no voltage, high voltage, or anything in between.  There is a 50V
| >electrolytic across the output which might break down and limit the voltage
| >a bit.  Based on my initial measurements (but after I had probably
| >disturbed the board) I'm leaning towards no voltage.
| >
|
| Is this a 1 watt 1n47xx ?

No, it's a 5W 1N5366.  I actually complained about the excessive heat
about 5-6 years ago (the board was starting to discolor even then) but
they said in effect that it was just a cosmetic issue since the zener
was rated for enough power.  And I suspect the zener itself is fine, it's
just the board that is destroyed...

| I have an ACT CR225 also and considering
| preemptively replacing with a higher wattage zener.

Couldn't hurt.  If I decide to repair the repeater I'll probably mount a
fresh zener away from the board, possibly with a heat sink.  The question
of exactly how the failure was causing the effect it was causing remains.

				Dan Lanciani
				ddl@danlan.*com