Lock-in Amplifier Built-in Oscillator Adjustment Model 5210 EG&G, Princeton, etc

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Mine is a PerkinElmer, but the 5210 instrument has had many identities--EE&G, Princeton Applied Research, Signal Recovery--but is always the same gear. What it doesn't have is a Service Manual or even a few pages on callibration in the Operators Guide. Mine could use an adjustment to the internal oscillator, but there are a lot of 'pots' under the hood and I don't want to make a little problem into a big one.

Does anoyone know where I might find some help? I have carefully searched the 'net with not so much as a schematic to show for my efforts.

Thanks in advance . . .
Donal

[Kleinstein]

I remember using one of these a long time ago. The old version (before 1995) I used had schematics in the printed instructions. I remember, because I had trouble with the DAC outputs  - I had to add series resistors to make it tolerate the capacitance of a 2 m coax. There was also a very similar 1 channel version - one might have a second chance with this model to find such an instruction online. So at least some (likely the older ones) of the manuals included schematics.

I don't remember exactly how the oscillator was made - I would expect something like an XR2209, as I remember it showed some drift, so not yet a DDS one.  Adjustments of an XR2209 / ICL8038 type FGEN should not be so difficult, even without a schematics.

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Thanks for the inspiration! I found the 5210 is still an active product of 'Signal Recovery' (a sub of Ametek, an establihed instrument company) and can be serviced by them. But I want it serviced by 'me' so I sent a nice email request for a pdf 'Service Manual.' Here's a link to a tech note: https://cpm.uncc.edu/sites/cpm.uncc.edu/files/media/tn1002.pdf
It shows a small square labled 'Internal Oscillator' . . .

That is as close to a schematic I've found yet.

[chuckb]

The older model 5104 has the schematics and alignment instructions. Maybe it will provide clues for you.

http://www.ameteksi.com/-/media/ameteksi/download_links/documentations/supportcenter/signalrecovery/instruction_manuals/18978-a-mnl-a.pdf?la=en

[lowimpedance]

There is one of these lock ins at work, but the handbook does not contain schematics or adjustment details unfortunately.
There is a block diagram and some basic descriptions of the block parts but similar top your posted tech note info.
So if Signal Recovery wont supply more information your only bet would be older models manuals you can find online.

[Kleinstein]

The single channel Version that is very similar should be the 5209.
I remember seeing a printed schematics in the instructions of either the 5209 or 5210.

For the block diagram it looks like the internal oscillator is a separate block and not used in the phase shift (e.g. as a PLL). So chances are that circuit part is rather well isolated from the rest and should not be that difficult to understand.

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From reading the 5104 instructions for calibration (cal/adjust), and from what I remember about the boards inside the 5210, the 5104 document is a big step in the right direction. Thanks! The report from the factory rep was that the unit should go back for calibration as "it is digital."

Right: if by that it means holding a tweaker between two digits.

The good news is that I ran some experiments to check out the function of the lock-in amp along the lines of a vid from YouTube and found everything as it should be except for the display of the internal oscillator freq. The internal oscillator oupput was spot-on, just not shown correctly on the LCD.

This moved this instrument into the "don't break it" category so I'll wait a while before 'tweaking' anything.