Re: DC to DC converter pinout

Shoot, I didn't think of that at all! In my testing I did ground the
"R" pin, since the ground pin was right next to it. Doing that made
no difference, there was still no 5vdc output. I neglected to put a
positive voltage on it. The Tech-2 DOES have a front panel on/off
switch (momentary). Now you've got me thinking the converter is NOT
at fault, it just needs voltage on the "R" pin to enable it. If that
is the case, I just spent 40 bucks at Jameco for a replacement I won't
need.

When I get back to the office tomorrow I will test pin "R" with a
simulated "pullup" voltage to see if that makes any difference with
the output of the converter. If the converter still tests dead and
the function of "R" is, indeed, an "on/off" switch, then I can live
with that. All we will loose is the ability to power down the device
when it is connected to power.

Thanks,

-Bill



On Mon, 17 Jul 2006 08:18:23 +1000, Franc Zabkar
<fzabkar@xxxxxxxxxxxxxxxxx> wrote:

On Sat, 15 Jul 2006 22:50:05 -0700, bill <bill@xxxxxxxxxx> put finger
to keyboard and composed:

My brother brought me a device known as a Tech-2 scanner, which is
used by GM dealers to troubleshoot and diagnose problems with GM cars
(my brother is the shop manager). He said the tech that was using the
scanner heard a POP, and then the device went dead. To get it
repaired via normal channels would cost over $800, so he wanted me to
take a shot at it first. I took it apart and the trouble appears to
be in a DC to DC converter that is mounted on the main circuit board.
It is made by BTCPower, and the part number is 4BE-01T-02. The IN
voltage is 7-18vdc, and the out is 5vdc at 2000ma. I went to the
BTCPower website and found the specs on the device, but apparently
these things can sometimes be manufactured custom. In the case of
THIS converter, the IN consists of THREE pins, a +, - and one labled
"R". The PDF on the web site does not have this extra "R" pin, so I'm
assuming it's a CUSTOM version the 4BE-01T device referenced on their
web site, specifically designed for use in the Tech-2.

I found and ordered a replacement from JAMECO electronics (#216961),
but it, like most other replacements I looked at, does not have this
"R" pin. I applied power (exactly 12v) to the old converter and
measured the voltage between ground and pin "R", and I read 4.77v. If
I raise the input voltage, the voltage across ground and "R" goes up a
little. If I lower the voltage the voltage across ground and "R" goes
down a little. So I'm thinking it some sort of "reference" voltage
used by the scanner for some reason.

Pullup resistor for Remote on/off?

See
http://www.btcpower.com/PDF/Datasheets/LP/B%20Series/3BB%20DS%20ver2.PDF

- Franc Zabkar
.