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 Post subject: Instruction manual for an Eico 470 oscilloscope?
PostPosted: Aug Wed 07, 2019 3:34 am 
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Location: St. Louis, MO
Note: NOT the more common 460. I got the construction manual (was also available as a kit), but I'd really like to have the instruction manual if anyone has it. I need to align mine after recapping it.


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 Post subject: Re: Instruction manual for an Eico 470 oscilloscope?
PostPosted: Aug Wed 07, 2019 4:29 pm 
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Location: Fernandina Beach, FL
If you don't find one, here is a guy who says that he has them, I think $17. No affiliation...

http://www.tinywebshop.com/Manuals/man_eico.html

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 Post subject: Re: Instruction manual for an Eico 470 oscilloscope?
PostPosted: Aug Wed 07, 2019 8:30 pm 
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The vendor doesn't define which manual he's selling (operating or assembly - the 470 had two separate manuals).

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 Post subject: Re: Instruction manual for an Eico 470 oscilloscope?
PostPosted: Aug Wed 07, 2019 8:42 pm 
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Location: St. Louis, MO
That site is where I got my assembly manual.


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 Post subject: Re: Instruction manual for an Eico 470 oscilloscope?
PostPosted: Aug Thu 08, 2019 12:32 am 
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Location: forked river , n.j. , usa
http://bama.edebris.com/manuals/eico/470/


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 Post subject: Re: Instruction manual for an Eico 470 oscilloscope?
PostPosted: Aug Thu 08, 2019 1:16 am 
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Joined: Jul Mon 01, 2019 4:42 pm
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Location: St. Louis, MO
That's the construction manual, not the instruction manual.


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 Post subject: Re: Instruction manual for an Eico 470 oscilloscope?
PostPosted: Aug Thu 08, 2019 4:39 am 
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Joined: Jun Sat 09, 2007 8:14 am
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Location: Florida
I looked at the schematic and the only "alignment" I see is setting the input compensation. In general this is a matter of tweaking the trimmers until a square wave is displayed as square as possible. The procedure for the 460 will give you an idea of this.

RRM


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 Post subject: Re: Instruction manual for an Eico 470 oscilloscope?
PostPosted: Aug Thu 08, 2019 5:10 am 
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Joined: Jul Mon 01, 2019 4:42 pm
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Location: St. Louis, MO
Funnily enough, I'm reading the 460 book right now...

There's 3 adjustments inside. 2 are trimmer caps for adjusting the 10 and 100 attenuator settings, C102 and C103. The other internal adjustment is called a very helpful "CAL. ADJ." in the construction book. It's R108 on the schematic. I have no idea what it adjusts.

The 460 has a few more adjustment screws inside, so it's not directly similar.


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 Post subject: Re: Instruction manual for an Eico 470 oscilloscope?
PostPosted: Aug Thu 08, 2019 5:32 am 
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R108 adjusts the voltage on the internal calibrator. When you select the internal calibrator, is there some kind of note that indicates what voltage is used?

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"Measure voltage, but THINK current." --anon.


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 Post subject: Re: Instruction manual for an Eico 470 oscilloscope?
PostPosted: Aug Thu 08, 2019 6:17 am 
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Joined: Jun Sat 09, 2007 8:14 am
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Location: Florida
ZombieElvis wrote:
Funnily enough, I'm reading the 460 book right now...

There's 3 adjustments inside. 2 are trimmer caps for adjusting the 10 and 100 attenuator settings, C102 and C103. The other internal adjustment is called a very helpful "CAL. ADJ." in the construction book. It's R108 on the schematic. I have no idea what it adjusts.

The 460 has a few more adjustment screws inside, so it's not directly similar.


The circuits are not identical because they are different models but the principle is the same and it's not complicated.

RRM


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 Post subject: Re: Instruction manual for an Eico 470 oscilloscope?
PostPosted: Aug Thu 08, 2019 11:12 am 
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Joined: Sep Thu 23, 2010 6:37 am
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Location: Powell River BC Canada
Eico 460s ran hot and needed attention to keep the DC amplifiers happy.
And charred resistors were known to unsolder themselves from the
printed circuits.

On the bright side it had a fine trace with a lighted graticule.

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 Post subject: Re: Instruction manual for an Eico 470 oscilloscope?
PostPosted: Aug Thu 08, 2019 4:51 pm 
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Joined: Jun Sat 09, 2007 8:14 am
Posts: 3911
Location: Florida
radiotechnician wrote:
Eico 460s ran hot and needed attention to keep the DC amplifiers happy.
And charred resistors were known to unsolder themselves from the
printed circuits.

On the bright side it had a fine trace with a lighted graticule.


Huh? I built my 460 about 1967, it's still in use, has none of those problems, and doesn't use printed circuits. It's all hand wired on a metal chassis.

RRM


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 Post subject: Re: Instruction manual for an Eico 470 oscilloscope?
PostPosted: Aug Thu 08, 2019 5:38 pm 
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Joined: Sep Thu 23, 2010 6:37 am
Posts: 11803
Location: Powell River BC Canada
I have about four 460s, and I built at least one in the past. And I remember
parts on a board close to the CRT socket getting very hot and loose.

Also I remember a 300 ohm twin lead from the front preamp section
to the board at the back.

I will go to the pile and have a look as it has been about forty years
since touching one.

(there is mention of a late version of the 460 using a solid state power
power supply and no 6AX5) -- just a mention..

If I have one of these, I'll take a photo.

_________________
de
VE7ASO VE7ZSO
Amateur Radio Literacy Club. May we help you read better.
Steve Dow
ve7aso@rac.ca


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 Post subject: Re: Instruction manual for an Eico 470 oscilloscope?
PostPosted: Aug Fri 09, 2019 2:03 am 
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Joined: Jul Mon 01, 2019 4:42 pm
Posts: 200
Location: St. Louis, MO
Retired Radio Man wrote:
The circuits are not identical because they are different models but the principle is the same and it's not complicated.


Well that's good to hear that it isn't complicated. The problem is that I'm a newbie and have never aligned an oscilloscope before. I can fix anything... IF I got the correct manual. Any pointers would be greatly appreciated!

pixellany wrote:
R108 adjusts the voltage on the internal calibrator. When you select the internal calibrator, is there some kind of note that indicates what voltage is used?


Nope! The construction manual says follow the tests in the Operation section of the instruction book.


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 Post subject: Re: Instruction manual for an Eico 470 oscilloscope?
PostPosted: Aug Fri 09, 2019 2:15 am 
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Joined: Jan Tue 10, 2012 8:39 am
Posts: 787
Well it doesn't much matter what voltage you use as a calibrator, as long as you know how much it is. I suggest running the control over its range to see what you get, and then returning it to its former setting. Once you establish what it can do, the proper figure will be obvious. Usually one Volt or 5 Volts, etc. Then you can watch it and adjust gain to get the required number of divisions.


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 Post subject: Re: Instruction manual for an Eico 470 oscilloscope?
PostPosted: Aug Fri 09, 2019 2:19 am 
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Location: Lincoln City, OR 97367
Greetings to ZombieElvis and the Forum:

You wrote:

Quote:
The other internal adjustment is called a very helpful "CAL. ADJ." in the construction book. It's R108 on the schematic. I have no idea what it adjusts.


You have two threads on this instrument. If you go back to the other thread:

viewtopic.php?f=6&t=362339&hilit=+Eico

...in the last post, I told you exactly what R108 was for and how to set it.

Please do take care to read what people write here, otherwise it becomes a waste of everyone's time.

Regards,

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KB6GM


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 Post subject: Re: Instruction manual for an Eico 470 oscilloscope?
PostPosted: Aug Fri 09, 2019 3:09 am 
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Joined: Jan Tue 10, 2012 8:39 am
Posts: 787
R108 adjusts the calibrate voltage, which apparently comes from the 6.3 Volt transformer winding. Since that starts out at about 20V p-p, I assume the pot sets the voltage somewhere around 1 Volt p-p or maybe 5 v p-p. It's not stabilized so it's only approximate. (The diagram shows no resistance values.)

A better way might be to clip the sine (before R108) with a pair of zener diodes and calibrate to that. Then you have a voltage that doesn't vary with the power line. But these kits were very price sensitive and a pair of diodes would have had too much cost impact.

There are many ways to improve this oscilloscope but most who own it probably want to keep it original. If you want better performance there is no shortage of inexpensive options.


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 Post subject: Re: Instruction manual for an Eico 470 oscilloscope?
PostPosted: Aug Fri 09, 2019 3:55 am 
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Joined: Jun Sat 09, 2007 8:14 am
Posts: 3911
Location: Florida
radiotechnician wrote:
I have about four 460s, and I built at least one in the past. And I remember
parts on a board close to the CRT socket getting very hot and loose.

Also I remember a 300 ohm twin lead from the front preamp section
to the board at the back.

I will go to the pile and have a look as it has been about forty years
since touching one.

(there is mention of a late version of the 460 using a solid state power
power supply and no 6AX5) -- just a mention..

If I have one of these, I'll take a photo.


There's a metal sub-chassis near the CRT socket with a twin lead to the front end.

RRM


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 Post subject: Re: Instruction manual for an Eico 470 oscilloscope?
PostPosted: Aug Fri 09, 2019 5:48 am 
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Location: Lincoln City, OR 97367
Greetings to Bob91343 and the Forum:

The schematic with the parts list on the side (for values) was posted by the OP at the following URL:

https://imgur.com/p0IwJ7a

Based on this drawing (with parts list) I built a quick and dirty LTSpice simulation of the calibrate circuit. The voltage that can be obtained at the calibrate switch contact (junction of R106 and R107) ranges from 250 mV peak-to-peak to 600 mV peak-to-peak. Therefore, I recommended that a 500 mV external, accurate 60 Hz signal be introduced into the scope at the front panel input terminals and that this signal be set for 10 divisions of peak-to-peak amplitude. Without changing the scope gain controls, the scope should be switched to the calibrate mode and R108 adjusted for 10 divisions peak-to-peak. This will calibrate the scope at 60 Hz. How well the calibration will hold at higher frequencies is anybody's guess, but this should be pretty good for a service grade scope.

If you want the LTSpice file, you will have to PM me; .asc extensions are not allowed by the ARF software.

Regards,

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 Post subject: Re: Instruction manual for an Eico 470 oscilloscope?
PostPosted: Aug Fri 09, 2019 8:46 pm 
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Joined: Jul Mon 01, 2019 4:42 pm
Posts: 200
Location: St. Louis, MO
Jthorusen, you sure did. I'm sorry. I never got past the graticule part of that post. I looked up on Google maps where the nearest office supply store was and the 2 closest to me have closed since I was there last, then I got distracted trying to fix my signal generator. You know how I said I can fix anything if I got the manual? That's a slight lie. I'm not even sure if the panel meter works right. First I had a sticky needle, then once I got that cleaned out, I still can't figure out why I couldn't calibrate the RF output right.

You mentioned a transparent sheet. Has anyone made a replacement graticule before? I've been searching around online for transparency films for overhead projectors. I can whip up an evenly spaced grid in Excel. My tube is a big'gun at 7", but an 8.5" sheet should cover that just fine. Would something like this work? https://www.amazon.com/dp/B07KS3VTQQ/re ... tDb6PD53FF

I decided to check R108. Apparently they used every single drop of flux they had on it. It's now glued shut and its resistance values are jumping all over my VTVM and DMM. Ehh, never mind. I was able to work it out smooth though I never did get it open.


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