Tuesday, June 22, 2021

fixing old stuff

Troubleshooting two big old Tektronix 7854 in my garage. The first analog oscilloscope with a computer. An oscilloscope lets you "see" electricity.
 
Currently I am checking the LV power supplies. I think I can operate them completely out of the scope.
 
I hope it will be an advantage to be able to compare one scope to the other. I have already found a few things
 
I have the 3" thick paper Tek manual with beautiful foldout diagrams and all the update pages (late issue).
 
And I have a third working 7854 on a cart in the house. I can always open that one up too :)
 
Why do this?
 
These scopes might be forty years old. A modern $400 oscilloscope from China does more, better, smaller, lighter, and is way cheaper (but probably not with 400MHz bandwidth).
 
The 7854 was introduced in 1981 at a base cost of US$10,500. In my 1987 Tek catalog it lists for $16,220 but by then included the waveform calculator and the extra memory option. Project Leader on this scope was Tom Rousseau. More about Tom and the 7A26 amplifier.
 
 
Thanks for your interest.
 
George Plhak
Lions Head, Ontario, Canada

 

Wednesday, May 19, 2021

easy change


John Deere Easy Change oil system

Today I tried to change the "Easy Change" oil filter on my cute little John Deere E120 lawn tractor. I am supposed to easily remove a canister that contains the filter and about a third of the engine oil and replace with a fresh unit. No need to drain the oil, they say. Cost locally at Home Despot is C$70. They call it Easy Change. First time I have tried it. It was anything but easy.
 
Normally, an oil and filter change takes about a hour if done carefully and costs about $20 with good quality oil and filter. Virtually all of the engine oil gets replaced with new, not just a portion.
 
But I am stuck. The old canister came off with some effort. Push and turn counterclockwise they say. Difficult to remove but it seemed to come off OK.
 
The new filter did not lock into position as it should. It is in the middle and it is really stuck. There was a click but I cannot remove it or force it to the fully locked position
 
In a conversation this morning with my local JD dealer 1 hour away they say "put the tractor on your trailer and bring it in. We will get it off for you while you wait". Thanks. I don't have a trailer.
 
<more conversation with the dealer>
 
I am going there tomorrow to get the parts to remove the "Easy Change" oil filter system and replace with a conventional filter and drain port.
 
JD equipment with an Easy Change oil system can be fixed. 
 
It is a bad idea that can be retrofitted for less than the cost of one canister.
 
Big Thanks to <my local JD dealer> for help.
 
Thanks for your interest.

George Plhak
Lions Head, Ontario, Canada

 

Thursday, January 21, 2021

infrared camera

INDEX to the series

In my never ending quest to reduce household energy use, I have added a Hti-Xintai HT-18 Thermal Imaging Camera to let me see HEAT.

First day reaction: this is VERY COOL.

I can now see an accurate temperature image from a distance on a small handheld display. But not thru glass.

In this picture, I am looking at an inside wall and noticing gaps in the insulation.

A whole new infrared world has opened for me.

This is my wood stove at moderate heat in the infrared (IR, below visible light).

The WHITE marker at the image center (126.2C) shows the temperature at that point. The value is also shown in the upper left. The measurement point is on the door, just off the window, where I happen to have pointed the HT-18 when I pulled the trigger to take the picture. This is the center of the instrument.

The RED marker above and to the left of center (145.7C) is the warmest point on the image. That value is also shown on the bottom line as MAX.

The GREEN marker at the top left is the COOLEST point on the image (14.2C). Also shown on the bottom line as MIN. The MIN is near the bottom edge of a window so it would be cooler.

When watching the HT-18 live, the red and the green markers move around on the screen as conditions change. They can be turned off since they can be distracting.

The bottom line can also be turned off.

Bottom right is the time of day.

At top center right is the emissivity setting. The default is 0.95.

Top right is the battery condition. I have been getting several hours at least on a battery charge.

Interesting about the wood stove is the camera's inability to see through the glass in the stove door to the very much hotter embers of the fire inside the stove. This is related to the emissivity of the glass. Smooth shiny surfaces do not emit well. 

It is fun wandering around the house with this.

HT-18 has two cameras, one "sees" normal light, the other infrared (IR).

It is possible to see (and take pictures of) visible, IR or varying overlaps of the two on the built in display.

In this pic, I have shown the visible image of my gas furnace on the left and the IR image on the right as two separate pictures taken one after the other. The furnace has just finished operating.

The scale at the right shows the colour code from white (HOTTEST) to black (COOLEST).

HT-18 has 5 different color code scales, selected in the menu, two are B&W (no colour).

This GFI outlet upstairs has nothing plugged into it. It has no load yet it is slightly warm!

This is normal.

The tiny circuit which operates the GFI sensing consumes electricity and warms up.

When I put my hand on the outlet, it was barely warm. I don't think I would have detected it with my hand.

HT-18 was able to see the difference easily!

This is my electric water heater.

I have been wanting to add a blanket. Now I can see why I should.

 

 

 

 

 

The ceiling on second floor which has roof on the other side. Outside temperature is around freezing.

This is the HT-18 IR view with the colour code changed to white is cool and black is warm.

I can see the rafters and some of the nails.

Some gaps in the patchy (70 year old?) insulation show as white blobs.

Another part of the second floor ceiling.

I had previously identified this spot with a laser pointer temperature meter and marked spots with tape.

The insulation shows gaps (white blobs) clearly in the HT-18 IR image.

Interestingly, I had added the tape in mid summer, when the roof temperature outside was 60C. This spot was abnormally warmer than most of the ceiling, measuring with a spot beam thermometer. Much easier to see what is going on with HT-18.

A pic of my house from outside at night.

Notice how the basement is the warmest part of the house from outside.

This is probably not good.








This is one of my exterior doors from inside. Temp is -15C outside. I had thought this door was pretty tight. The door looks ok in visible light on the left.

Viewed with IR on the right with white cooler, black warmer mode reveals some problems.

The leaks at the bottom of the door are obvious.

Also the inside structure of the door is visible. This is a cheap hollow door and has cardboard strips glued inside to give the veneer panel some strength. The strips are clearly visible. This door is not a very good insulator.

Just above the waste basket is an electrical outlet which is glowing white. A light switch above it also glows white showing a cold leak.

I have much to learn. This is not a detailed review but a collection of first impressions and images as I learn. I am impressed so far. I think HT-18 will be very useful.

As a footnote, I have another Hti-Xintai instrument, HT-2000 CO2 meter which continues to give good service. I am a satisfied paying customer not a paid reviewer. Web ordering on Hti website, via Amazon or Banggood.

Thanks for your interest.

George Plhak
Lions Head, Ontario, Canada

INDEX to the series