Test jig for testing Audio Reg II pcbs

A while ago I asked the VL-gestalt about how to go about testing my 3ft
stack of Audio Reg 2 pcbs. No suggestions were offered. Whatever...

I did eventually get two going without trashing any boardsets (although I
vaporized a couple AR2 traces and de-smoked some components due to the
p6/p9 connector issue)

For the first AR2, I used a World Series (Cinemat) board as a load. I had
to hook up the 5v, gnd and sense lines with a mess of alligator clips.
Very ugly but it worked.

I knew there had to be a better way. Then I remembered an old trick for
working on audio amps. Sometimes you need a good load on the outputs. The
quick & dirty solution is to use an automotive taillight bulb (used here
on the 5v line). I prefer this to a scrap boardset for three reasons.

#1: The brightness of the lamp can give you a rough idea happening on the
5v line. One AR2 would pump out 10.3v and the bulb was very bright. The
bulb should be a relatively dim glow.

#2: What would have happened if I hooked up said scrap pcb to the 10.3v?
Poof! I would need to get a new scrap board since numerous devices
probably would have shorted.

#3: This uses the game's harness so you can roughly set the 5v line
before hooking up an actual board.

So how can *you* make one of these?

Just send $19.95 to the address on your scree...oops, wrong script -
sorry!

I grabbed a 44 pin connector and fingerboard out of the pile of wire
harnesses that every so often tries to snare my leg when I walk by. You
could piece together a 44 fingerboard from the bits that get chopped when
JAMMAtizing a fingerboard.

From there its a simple matter to solder some wires to the bulb, connect
those to the 5v line and then wire up the sense lines (5v-> positive
sense, gnd->negative sense). You could also add some solid wire loops so
its easy to clip on DMM leads but I manage with stripping some extra
insulation from the wires I soldered to the fingerboard.

Stick the mess in your Space Duel (or whatever) and turn it on.

Now onto a slightly different topic...

I'm worried about one of these repaired AR2 boards going nuts and dumping
10.3v on the 5v line <cringe>.

I know John Robertson had suggested some sort of crowbar circuit but I
never followed up on it.

The mighty uber-hacker and all-around great guy Clay mentioned some
"crowbar diodes".

So has anybody done something like this or am I just paranoid?

Almost-lastly, is there a data sheet available for the round can (LM305?)
voltage reg on the AR2?

Finally, is there a source for these besides other AR2 boards?

Virtu-Al

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Received on Fri Dec 3 00:57:11 1999