Latest workbench additions

[stinius]

[/quote]
it's straight from a taiwanese second hand equipment dealer. [/quote]

Maybe you could attach a file with a link to that dealer? 

Cheers

[syn08]

Maybe you could attach a file with a link to that dealer? 

Cheers

Let me know what you are looking for and I'll check with those guys

They don't really have any online presence, they mostly do wholesale business with US second hand equipment dealers. Since I was in China back in the 90's, I have a personal relationship with one of the guys over there.

[stinius]

Ok
I will.
Thanks

[Pete Basel (PB2)]

Maybe you could attach a file with a link to that dealer? 

Cheers

Let me know what you are looking for and I'll check with those guys

They don't really have any online presence, they mostly do wholesale business with US second hand equipment dealers. Since I was in China back in the 90's, I have a personal relationship with one of the guys over there.

I have a client who told me last week he is ready to buy an:
Agilent Model 4156C Precision Semi-Conductor Parameter Analyzer

He is looking used and also has contacts in China but anything
you might know of we would appreciate a referral for.

Nice unit you got there by the way!

[syn08]

I have a client who told me last week he is ready to buy an:
Agilent Model 4156C Precision Semi-Conductor Parameter Analyzer

This is a current model at Agilent and it's over 40k (with a minimum amount of software which is, BTW, VERY expensive) new. It is unlikely it's available (or anywhere cheap) with my guys, but I'll check anyway...

[Pete Basel (PB2)]

I actually think there is a replacement model out already that is I think more modular.
It is a current model but I think it might be phased out sometime in the next few years.
They told me it "might" be phased out soon, then there would be 5 years of full support.
Thanks very much for looking into it.

[GK]

Here is the input stage schematic for the Tektronix 1A7 differential plug-in vertical amplifier. Due to the specified sensitivity of 10uV/division it's a low noise circuit with parallel triodes (nuvistors) in the input stage to keep the noise down. The tube input stage also has a bootstrapped cascode and an elaborate long-tail pair current source to keep the CMRR high and handle large common-mode signals.

I'm using this as the inspiration for the input stage of my latest (hybrid) build, but I'll be using Miniwatts instead of the nuvistors.
 
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[GK]

So, it seems that I'm the only one here enthusiastic about the old Tek stuff 

Here is another nice bit of kit that I totally forgot I had. It's a rack mounting power supply that allows you to use any of the dual channel vertical amplifier plug-ins independantly, with the ouput signals for both channels of each provided on the front panel. Real handy whenever a wideband, calibrated amplifier is needed. It also contains a multivibrator with a calibrated attenuator to provided a square wave calibration signal. I'm gonna clean this one up and stick it into my testbench rack.

[megajocke]

Beautiful 

I saw something similar in a local online auction. One channel though and loaded with a differential amplifier plugin. Should have bought it - the old stuff really has impressive quality.

[GK]

the old stuff really has impressive quality.

It sure has. Some of the old HP stuff is nice too, but the Tek stuff is still the best. It says something about the quality of the build and the components used that after 50 odd years these machines are still running. Pics attached show inside the 575. The components are soldered (with silver containing solder) to ceramic terminal strips. I wonder how many man hours went into the assembly of one of these.

[Edmond Stuart]

[snip]
The components are soldered (with silver containing solder) to ceramic terminal strips.
[snip]

Does this one still have the little spool of silver solder for repairs, bolted inside the chassis?

Edit: Here's one my oldest piece of equipment: a HP181A storage oscilloscope.
Not as nicely built as a Tek, but, as you see, still working after 40 years.
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[GK]

Does this one still have the little spool of silver solder for repairs, bolted inside the chassis?

It might have. I'd have to pull the cover on the other side and have a look. I've got a HP scope that looks identical to yours. Got it for $20 non working. That little fiddly power push-button to the lower left of the display was broken. After shorting the power switch out the scope came alive but it had triggering issues. Something to look at again when I have the time. With it came the original service manuals, in HP microfiche!

EDIT: Just pulled it out. Mine's a 180A mainframe with a 1801A dual channel vertical amplifier and a 1820C timebase.

[Pete Basel (PB2)]

the old stuff really has impressive quality.

It sure has. Some of the old HP stuff is nice too, but the Tek stuff is still the best. It says something about the quality of the build and the components used that after 50 odd years these machines are still running. Pics attached show inside the 575. The components are soldered (with silver containing solder) to ceramic terminal strips. I wonder how many man hours went into the assembly of one of these.

The old Tek stuff is nice, but my view is that it is just not worth the maintenance given the performance level it provides.  I don't have to spell it out for you, you certainly know what I'm talking about.  I currently have a Tek 7704 that I got at a very good price but had to repair.  The repair was easy - a shorted Tantalum cap.  It is 200 MHz and takes an assortment of plugins.

I have a Tek 532 tube scope that is similar to what you're showing, needs to be gone over and I'm willing to give it away to someone
who will actually use it and not part it out for profit.  Pick up only in Connecticut, 06611.

[Pete Basel (PB2)]

My first employer out of school had a new tek 7704A when they had just come out.  It was the first really good scope that I ever used and it was really expensive.  I believe around $20K or more - you can get them cheap now on ebay:
http://www.prolexdesign.com/images/tek7704a.jpg

http://www.jvgavila.com/tek7000.htm

It is rather large and bulky, the rack mount version might be better in that regard, and there are faster versions also.
The common plug-ins go for 10-$25 on ebay last I checked.