Stanford Research SR715 LCR Meter Teardown - Page 1
Forum section: electronics / testgear

author: barnacle2k
author_rank: Regular Contributor
timestamp: July 22, 2015, 10:48:23 pm
content: Because of all the recent talk of LCR Meters, here my newest acquisition fresh from ebay:A Stanford Research SR715 LCR Meter, it boasts a 0.2% base accuracy rating.It came with the full manual in a binder, as always with Stanford Research gear the manual contains the full schematics.Also included a nice pair of Kelvin clips.Did some basic measurements to test it out, but I don't have any capacity or inductance standards.It has a RS232 interface for PC connectivity, the GPIB option is not fitted.Another nice feature is the external bias connection via banana plugs on the back for up to 40V or 100mA.Measuring 100n 5% Wima:Small hand-wound inductor 100µH calculated:1.000K resistance standard:100.00K resistance standard:How well does it measureLOW ESR? (Yes that is a 1000µF 1200V foil CAP)A big old inductor (rated 4.7H @ 100mA):1000µF standard capacitor:The very nice manual:Original cal certificate included:TEARDOWN time (4 Screws later:)Boring switch matrix:The money shot:Beefy protection circuitry and filter caps: (Nichicon of course)The only SMD part I could find on that board:Dale precision resistors:CPU is a Zilog Z80:Under the input:

author: Lightages
author_rank: Unknown
timestamp: July 22, 2015, 10:52:36 pm
content: Thanks for the look inside. It is always interesting to see how different designs of the cases have converged over the years. That is a very different looking case. Also interesting is the neon lamp being used as a "spark gap".

author: AF6LJ
author_rank: Unknown
timestamp: July 22, 2015, 11:24:25 pm
content: Thanks, nice tour through that LCR meter.

author: Vgkid
author_rank: Super Contributor
timestamp: July 22, 2015, 11:35:04 pm
content: Thanks for the teardown, i guess i will post the insides of my bridge.

author: Salas
author_rank: Frequent Contributor
timestamp: July 23, 2015, 02:38:15 am
content: Very nice pictures. The form factor reminds of cash registers though. Weird choice for test gear.

author: TiN
author_rank: Super Contributor
timestamp: July 23, 2015, 04:33:55 am
content: Nice LCR. And that cap is enormous..

author: barnacle2k
author_rank: Regular Contributor
timestamp: July 23, 2015, 09:27:01 am
content: The form factor is a downside, its not rack or stack-able.But i recall a lot of bench, LCR meters had this kind of formfactor, the Telemeter Electronic LCR Databridge units for example.It might be due to the manually operated LCR bridges being a flat tabletop kind of deal.Quote from: TiN on July 23, 2015, 04:33:55 amIts quite a beastySpecs:RMS: ripple current 100Ampsshort circuit current: 35kAmpsESR: 400µOhmESL: 50nHenergy content:666Joules (demon capacitor out to kill me?)

author: commie
author_rank: Frequent Contributor
timestamp: July 23, 2015, 01:46:34 pm
content: One of the nicest boards I have ever seen. Take note the use of Z80 microprocessor(Von Nuemann) whilst PIC/AVR are Harvard. Nice!CheersCommie

author: HighVoltage
author_rank: Super Contributor
timestamp: July 23, 2015, 03:03:51 pm
content: Quote from: barnacle2k on July 23, 2015, 09:27:01 amA long time ago, I owned a Wayne Kerr 421- LCR meterIt had also a similar strange form factor.As I see, they are also around for sale....Nice tear down, btw.Thank you for sharing those great pictures.

author: PA4TIM
author_rank: Super Contributor
timestamp: July 23, 2015, 04:15:44 pm
content: This was is the GR digibridge. Looks like these calculator/typewriter style cabinets were populair in the 70's

author: PaulAm
author_rank: Frequent Contributor
timestamp: July 23, 2015, 04:27:37 pm
content: I was looking at one of those for a while, but ended up with an HP 4262a. It's a little easier to stack.

author: cnqhdszq
author_rank: Regular Contributor
timestamp: February 26, 2017, 02:21:26 am
content: I need the diagrams of SR715 ,may you take photos of it and Email to me ? E-mail : qhdszq@126.com thanks

author: JonM
author_rank: Unknown
timestamp: February 26, 2017, 02:44:17 am
content: Quote from: cnqhdszq on February 26, 2017, 02:21:26 amYou can download the manual from SRS:http://www.thinksrs.com/downloads/PDFs/Manuals/SR715720m.pdf

author: JonM
author_rank: Unknown
timestamp: February 26, 2017, 02:54:40 am
content: Quote from: JonM on February 26, 2017, 02:44:17 amHowever, I now see that the manual ends with the parts list on page 7-12 and no schematics included. Now I know that I may be missing information in the mis-placed paper copy of the manual for my SRS560.

author: cnqhdszq
author_rank: Regular Contributor
timestamp: February 26, 2017, 07:31:32 am
content: Yes The manual does not have diagram in.

author: guenthert
author_rank: Frequent Contributor
timestamp: February 26, 2017, 04:55:32 pm
content: Quote from: commie on July 23, 2015, 01:46:34 pmWell, barnacle wrote "Z80", but in the picture you can clearly see a Z8, which happens to be a (Harvard architecture) microcontroller (quoting Wikipedia here, as I've not encountered that chip myself. It's a bit, er, dated).

author: bluesystems
author_rank: Newbie
timestamp: February 16, 2021, 08:49:25 pm
content: I see by your post you have the schematic diagrams in your pictures of the manual for the SR715.My SR720 has started producing "Out Error 1" on power up and I could use a set of schematic diagrams to sort it out.In the past Stanford Research has supplied schematic diagrams on request for a moderate fee. This seemed fair.When I requested this time service documents including the schematic diagrams their response was disappointing . I received."We don't supply schematics with the SR720. You will probably want to send the product back to SRS for service."For me it is uneconomic as the unit will have to be shipped internationally.Stanford Research seems to be no longer interested in allowing their customers to support their own equipment. I find this very disappointing and short sited.I wonder if you would consider sharing your copy of the schematic diagrams so I can get my SR720 back up and running.Thanks for any reply. Bob J

author: korlatos
author_rank: Regular Contributor
timestamp: October 24, 2023, 10:37:54 pm
content: For some reason, SRS now includes schematics in the manual posted on their web site.

author: korlatos
author_rank: Regular Contributor
timestamp: October 24, 2023, 10:45:18 pm
content: File now attached.

author: coromonadalix
author_rank: Super Contributor
timestamp: October 25, 2023, 08:19:44 am
content: few years ago they wanted 125$ usd to get a manual copy + schematics lolllthks

author: Kosmic
author_rank: Super Contributor
timestamp: October 26, 2023, 03:41:03 am
content: They also added the Calibration, Troubleshooting and Maintenance section of the manual

author: maxwell3e10
author_rank: Frequent Contributor
timestamp: October 26, 2023, 04:30:40 am
content: It looks like they posted manuals with schematics for a majority of their products!

author: coromonadalix
author_rank: Super Contributor
timestamp: October 26, 2023, 04:00:18 pm
content: are they gonna close ?? strange behaviour ??

author: Kosmic
author_rank: Super Contributor
timestamp: October 26, 2023, 06:09:46 pm
content: I think they just updated the manuals on their web site and for some reason decided not to lose time by creating stripped down versions.It's not like the added (not removed) sections were not in the manual in the first place.

author: tuanpq
author_rank: Newbie
timestamp: August 13, 2024, 09:06:13 am
content: can someone upload the LCR firmware? thank you

author: Kosmic
author_rank: Super Contributor
timestamp: August 15, 2024, 05:56:33 pm
content: here's the firmware for a SR720 v 1.03will probably not work on a 715 though

author: BillyGo
author_rank: Contributor
timestamp: September 19, 2024, 01:22:48 am
content: I just noticed my SR720 is behaving weirdly for components with a high Q factor, for MKP capacitor the D factor always goes above 0.004 and the Q factor just jumps from 800 to 1200 randomly. The reading can only be stabilised unless I set the frequency to 10KHz, but still not in the range for what it is supposed to be.It makes me start worrying about the testing I used to do for inductors and coils in the past few years