Avo 36 range restoration

All the case screws were missing, except one that was broken inside the front panel, i was able to take it out.

Behind the scale plate there is a number wrote with pencil...

See more photos.

[The Philpott]

Told you it would turn up! It must have looked very interesting on an x-ray, particularly with variable contrast.

I wonder whether the fuse is intact and how many ohms it is..?

Dave

The fuse is 1,3 Ohm


At the left of the second photo there are 5 resistors in parallel... 47 ohm, do not understand why someone will use 5 resistor to get that value. See photo of the monster!

I just found the electrical diagram in this thread, thanks!!

Superscope, could you load a photo of the left hand spike and leaf connectors?

thanks

[The Philpott]

Fuse been modified from 4 ohms then.
I suppose with a magnet that rusty you could use oiled 600 grade silicon-carbide paper so the rust can then be wiped away with a cloth. It's still a very nice purchase, i am sure you can reverse the bad work that has been done.

Dave

Thanks!!

I repaired de swamp bobin, it was horrible rewind and with lot of tape. I glue the Bakelite bobin and rewind better the last 2 70 inches that are not original, then with a special tape for car wires, that is made of “cloth” I cover it a bit, also put a plastic spacer behind the bobin and the movement.

One of the big screws that fix the movement was missing due to the nut in the Bakelite front is over screwed (I think is called like that) I must have a good idea and help to repair that.

Also repair a couple of shunts. And tried the movement and it is working.


The paint of the scale is in very bad condition only breathing near it the paint goes off.
Do not know what to do apart is scanning it. Is there any posibility to stop that flaking? Perhaps with same kind of transparent varnish? Not sure because the problem is between the nickel and the paint, not over the paint.... any idea?

[The Philpott]

Calibrated at 85 Fahrenheit? My meter from two years earlier has 20 Centigrade/Celsius on the scale plate.....So was your one originally designed for export to the USA?...Could be.

D

[The Philpott]

(That might be 65F, i can't quite see..) D

[Superscope]

Hi Aitor,

If you can stabilize the Paint on the Scaleplate that would be better.
You still have more than enough left of the original for a good restoration.

Unlike mine (First Pic) which simply won't do the Job anymore.

Interesting about your broken Case Screw.

I have exactly the same issue with what looks like the exact same Screw (Second Pic).
Although I have not managed to get it out yet.
It does appear to have a Screwdriver Slot in it, so this may have been some type of security Screw.

Not sure exactly what you meant by Leaf connectors. Do you mean the Switch or the Battery connectors?
(See Pic 3 for the left Spike looking from the back, not sure if this is detailed enough for what you want).

I did notice that the Brass Fingers holding in the Glass on your meter seem very different
from the Normal ones found. (See Pic 4).

Pic 5 is a more detailed view of what's left still attached to my Meter at the Moment.


Ian

It is 85 F

I just scanned it.

A few paint peel off during transportation (in a bag) and during the scanner

Scale and serial number saved!!!

Originally Posted by Superscope

Hi Aitor,

If you can stabilize the Paint on the Scaleplate that would be better.
You still have more than enough left of the original for a good restoration.

I gave my friend, the same that draws the terminal cap for printing in 3D, the scanner, he is going to do a good job. If you want, scan yours at 600 dpi and send it to me, my friend will complete yours and put your serial number.

Today i print the scanner as is in a good paper to see the aspect, and is quite good. On the other hand, i bought a very good varnish, colorless and applied it in spray after cleaning it. several paint peels off only for moving it on the table. But the result is acceptable. I think i will use the original scale with the varnish, and will prepare a good copy for the (lets hope) far future. So no problem to restore your scan, for free, and no taxes.

Originally Posted by Superscope

Not sure exactly what you meant by Leaf connectors. Do you mean the Switch or the Battery connectors?

Originally Posted by Superscope

(See Pic 3 for the left Spike looking from the back, not sure if this is detailed enough for what you want).

Yes, thank you, there you can see what i "called leafs" the multiple switch.[/QUOTE]

I clean and repaint the front panel.

Before/after

Yesterday night i repaired the P and R and /2 knobs, now they move softly and also cleaned the resistors.

Also painted in white the /2 knob, that i forget to do it before.

Today i will try in my job with the 20X magnifying glass to find the extremes of the broken of the different resistors boards, one is broken in the middle, so the job will be more than difficult.

Also, I want to re assemble the movement with the original varnished scale and try it to FSD.

There are 2 no original resistors with un known value, in parallel one is open and also broken, i can see the interior, the other one is open too. They are connected to the transformer and 12 A AC and 12 Volts AC. I will try with the electrical diagram to clarify why they are there.

[Superscope]

Aitor,

If your Resistors are connected to the Transformer and the AC 12 Amps/Volts line,
then this is the 96 Ohm resistor I re-wound and mentioned in my previous post.

I think on your Meter these are not likely to be original.

The 96 Ohm winding should be wound on the very end of the Small resistance Board.
i.e. looking in from the back, it is the very left Winding on the Board that is
bolted next to the Transformer.


On the Picture attached, the 96 Ohm Winding has been re-wound, The one on the Left.
Unfortunately for me, the Winding at the other end is/was also OC and I am in the process
of re-winding this.
I have unwound the original Wire, which then Broke in several more places.

Re-winding the Shunts is not an easy task, especially for the very long ones, which is
why it is not often done.
Manganin Wire is also very expensive and almost impossible to find in the lengths and Values required.


Ian

Yes, thank you, i thought it was the 96 Ohm resistor, somebody put it there instead of soldering it on the board and in that position looked like very rare for me and i was not sure it was the 96 Ohm one.

Do you know who can rewind that shunts with the appropriate manganin wire?

I repaired few of them, but 3 or for are irreparable due to multiple breaks in the middle...

Thanks

[Ed_Dinning]

Hi Aitor, you may be able to get the shunt materials from the Scientific Wire Co.
If you know what types you need I'll see what I have in my small collection of nichrome etc wires.

Ed

Thanks very much!!

First steps on restoring the scale with the computer. See photo

The idea is to print if it is necessary the scale directly on the metal (serigraphy). The mirror arc will be cut in the computer, so it will be possible to print directly on the polished metal and the mirror will be saved. Or could be print in a paper and then glue it to the metal, in this last case cutting the arc will be necessary.

Today, in my job with the binoculars, i tried to repair the shunts, i was able to repair 2 of them, but others has several wires broken and in fact that i solder few of them, they continue being opened... So i will fix them provisionally with resistors until i found where can i send the shunt to be rewind.


On the other hand, i found a workshop that works with metal and uses jet water and laser cutter machines. I will replicate the battery cover for this AVO 36 with the measurements that Superscope kindly said in this thread, 145Mm X 56Mm.

[The Philpott]

It seems now, that in every corner of the globe, someone is going 'beyond the call of duty' to repair these things. I am very impressed.

Goodnight everyone.