[time-nuts] OT: Prologix GPIB and HP3478A...It's Alive!!!

Chuck Harris cfharris at erols.com
Fri Nov 30 09:05:18 EST 2007

Hi Abdul and Group,

I'm beginning to feel like I am a manic depressive.. I keep going from
the lowest lows to the highest highs...

Well things are pretty high right now.  Here's how I got there:

First, I took my Prologix adapter apart to have a look see under
the microscope.

... Abdul probably won't speak to me ever again after I describe what
I did...  But I'm an engineer.  I can't help myself.  It's in my genes.

In looking the board over over, I discovered that one of the data pins
on the GPIB connector was bent out of line where it passed into the
board.  A classic sign of solder blocked hole that prevented the pin
from passing through the board and getting soldered.  This is it, I thought.
The pin even wiggled funny.  So I needed to take the thumb screws out and
get to the bottom side of the board and repair the joint.

Well, Abdul obviously didn't want me to do that, as he epoxied a nut
onto each screw to keep it retained... a little over kill there
Abdul.  I like that!

If you ever run into something like this, your soldering iron can be your
friend... that and a little patience.  I heated the nut until it was
smoking hot, and screwed the thumb screw right out...  Sounds much easier
than it really was... That's where the patience part comes in.

After I got the board out, I discovered something odd, the pin that was
bent up stuck through the board enough so that Abdul had clipped off
the excess after soldering the board.  Hmmm?  Well, I sucked out the joint,
straightened the pin, resoldered it, and tested the silly thing anyway...
Hope springs eternal, as they say.

It worked!  My 7854 was up and running, and being controlled, and all of
that really neat stuff, and t h e n,   i t   w a s    i g n o r i n g
e v e r y t h i n g    t h a t   I   s e n t   t o   i t...  Damn!

We are hitting one of those lows again.

So, I plugged my trusty HP85B into the scope, and tried to control the
scope, and ...   it didn't work either!

It's getting a little hard for me to escape the conclusion that there is
something  wrong with my scope, and it's an intermittent too... I love
problems that are intermittent.  They allow me to waste inordinate amounts
of time, speak new swear words I don't usually use.. All that kind of stuff
that makes it feel good to be a man.

The first place I decided to look was the 7854's GPIB connector, since
the problem seemed to have something to do with exercising the connector.

When I got the connector where I could see it, I noticed that Tektronix
committed a major fooboo with this connector.  They needed it to stick
out from the board a little bit further than the solder tails would allow,
so they checked to see that nobody was looking, and just soldered the pads
with the solder tails somewhat below the surface... Not a great recipe for
success...  Or as someone once said it was one of those things that puts
the suck in success.

I sucked out all of the joints, and made triple damn sure that the new
joints were getting properly wetted with solder, and made a little fillet
on the other side of the board, and tried things out...and...

It works!!!

Remember what I said about manic-depressive?  Well this is one of those
high times.

It seems to be ok.  Now we just have to let it run for a while.  With
any luck at all, it will work long enough that I will completely forget
I ever went through this series of events.

Hopefully I can keep this mess running until I get my Tektronix 547
transformer core experiments finished, my report written, some pretty
pictures made, and a couple of transformers rewound.... We'll see.

Thanks Abdul for providing me with such good entertainment!

-Chuck Harris

Prologix wrote:
> Hi Chuck,
> Please make sure the adapter is properly seated. Also, see if using a GPIB
> cable makes a difference.
> If you are still having trouble I am happy to send you a replacement unit. 
> Regards,
> Abdul
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of Chuck Harris
> This is beginning to look more and more like I have a
> bad Prologix adapter.
> Oh Abdul??
> -Chuck Harris

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