Re: Asteroids/Asteroids Deluxe - Current Tracer for shorts

Hi Mike,

Ahh yes. I have the 546A logic signal injector also.
I have some very vague memory of using it to trace power supply
tracks (dc) but think I must be wrong! :)

I'll dig it out and have a try of it, I can't find it at the moment.

I'd also use the big 5V supply method, and would find the
hot spot, but don't break the short off while the PSU is on (if it's a tantalum
cap or whatever) as a lot of PSU's will shoot up the output voltage briefly
if the load changes from eg. 15A to 1A in an insant, it may get over ~6.5V on a transient
and damage IC's.

I tried my Sony video camera that has the Nightshot function, and blocked the
IR light source on it, but couldn't see a working (normal-hot) board with it.
I could definitely see my soldering iron though!

thanks,

marc

----- Original Message -----
From: "Mike Mnemonic" <mike@nemonic.freeserve.co.uk>
To: <vectorlist@synthcom.com>
Sent: Saturday, August 25, 2001 9:05 AM
Subject: Re: VECTOR: Asteroids/Asteroids Deluxe - Current Tracer for shorts

> Marc,
> Regarding the HP signal tracer, I have one of those too and wanted to
> use it for exactly the same fault condition (short on power supply).
> However, this device can only trace pulsed currents as your description
> clearly states below. Therefore, it's no good for this type of problem on
> its own. You could probably use it in conjunction with the matching logic
> signal injector model 546A. Having said this, I still advocate the big 5V
> psu and use your finder to find the hot spot method which will have it fixed
> before you've got the HP kit set up and read the manuals ;-).
>
> Regards
>
> Mike Mnemonic
>
> ----- Original Message -----
> From: Marc Alexander <marc@wolfems.com.au>
> To: <vectorlist@synthcom.com>
> Sent: Friday, August 24, 2001 3:37 PM
> Subject: Re: VECTOR: Asteroids/Asteroids Deluxe - Current Tracer for shorts
>
>
> HP 547A Current Tracer
>
> “The HP 547A Current Tracer is a hand-held probe which enables the precise
> localization of low-impedance faults in electrical
> systems. The probe senses the magnetic field generated by a pulsing current
> internal to the circuit or by current pulses supplied by
> an external stimulus such as the HP 546A Logic Pulsers. Indication of the
> presence of current pulses is provided by lighting the
> indicator lamp near the Current Tracer tip. Adjustment of probe sensitivity
> over the 1 mA to 1A range is provided by the SENSITIVITY
> control near the indicator. The probe is self-contained and requires <75 mA
> at 4.5V to 18V, from any convenient source.”
> I don’t use this very often, but when I need it, I really need it. It’s used
> for finding things like shorted input gates, stuck
> tri-state buses and broken/shorted traces.
>
>
>
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Received on Mon Aug 27 18:43:20 2001