EEVblog #452 - Stanford Research SR430 Teardown

[EEVblog]

Inside the Stanford Research SR430 Multi Channel Scaler Photon Counter
Unboxing video here:

Datasheets:
http://www.physics.rutgers.edu/ugrad/389/muon/SR430m.pdf
http://www.elektronik.ropla.eu/pdf/stock/hit/hd63484.pdf
http://cds.linear.com/docs/en/datasheet/100737fbs.pdf
http://www.analog.com/static/imported-files/data_sheets/AD96685_96687.pdf
http://www.onsemi.com/pub_link/Collateral/MC10H107-D.PDF
http://www.datasheetcatalog.org/datasheet/SGSThomsonMicroelectronics/mXqzrvy.pdf
http://www.physics.brocku.ca/~edik/gpib/TMS9914.pdf
http://www.freescale.com/files/microcontrollers/doc/data_sheet/MC146818.pdf
http://www.analog.com/static/imported-files/data_sheets/AD586.pdf
http://en.wikipedia.org/wiki/Emitter-coupled_logic

[poorchava]

I saw a TEAPO capacitor. One of the most recognized "bad caps" brand 

[free_electron]

Reamwood avenue They're still there.. just a few traffic lights away from where i am.

[Cognito]

I noticed one thing on the PCB for the CRT. It seems that it uses four brands of electrolytic capacitors, based purely on the color. I don't know if that is usual or not, but why did they decide to do it anyway?

Great teardown Dave! I always learn alot

[bitwelder]

Dave, did you clean/vacuum the boards before shooting the video?
They were spectacularly clean for having 20 years of service behind.

[Scott]

Digikey carries the BPV10 photodiode and it has a 2.5 nS rise time and only costs $0.86.

Thorlabs charges $150US for a DET10A which is a 1 ns rise time Si diode in a nice box with a bias battery. The FDS02 diode from Thorlabs is $74, but has a 47 pS rise time. It's in a nice FC/PC mount so you can screw it onto the end of a fiber optic cable.

They charge $42 for a bare 1 nS rise Si diode, so that BPV10 is a great value.

Electro-Optics is fun!
-Scott

[CarlG]

Interesting video   of a long lived instrument! Surprisingly (at least to me) it's still running at SRS, would you believe it?!!

Suggested use from the datasheet:
The SR430 is useful in a variety of applications where it
is necessary to count events as a function of time: LIDAR,
time of flight mass spectroscopy, and fluorescence decay
measurements are just a few examples.

Obvious, isn't it

The -2V is the ECL termination voltage, not mentioned in the video I think.

Interestingly, it's 10H ECL series, not 100H, that is temperature compensated. Maybe a price issue, or that 100K was rather new at that time (correct me if I'm wrong). Or maybe 100H wasn't even invented then; I lost track somewhere in the beginning of the 90's. A lot of new ECL logic families seem to have emerged since then

Note also that ECL basically is "constant current" i.e. a device draws the same current in either state as well as during switching. Of course, the decaps are still needed

I think that the refdes starting number is defined by the schematic sheet number, e.g. 1000-series on sheet 10. I prefer to number passives along that scheme in multisheet schematics.

EDIT: for the interested: Onsemi 10H/10K app note

[JuanPC]

Hi,
can someone explain more about the Oscillator Dave is Explaining from Minute 33:25~34:41

It has a 25MHz PLETRONICS P1100HC, is rare to see an XO with so many .000000
www.pletronics.com/files/index.php/p1100-hc.pdf?
TCXO with 1ppm has only .0000
anyway...
near has a 74HC191 counter...?
http://www.datasheetcatalog.com/datasheets_pdf/C/D/7/4/CD74HC191.shtml

bottom has a schmitt trigger working as a Oscillator, MC10H116P.
from the resistor ^ the cap to ground looks like a Osc.
http://en.wikipedia.org/wiki/Schmitt_trigger#Use_as_an_oscillator
L301 looks like a variable coil.

how oscillates at 200MHz_?
has 0.5~1.6ns Rise & Fall, pretty decent, but enough for 200MHz_? 300Mhz oscilloscope has 1ns Rise & Fall.  could be.

goes to the SP4633 /64 prescaler high speed 1Ghz divider... _? that means the Schmitt LC-Osc is generating more than 200MHz_?

MC10H125 quad translator for interfacing data and control signals between the MECL section and saturated logic section of
digital systems.? has a Rise&Fall 0.3~1.2ns. im lost here, could it be just to change the voltages to something the next understands_?

the MC10Hc125P goes to the MM74HC4046 PLL... the VCO has 12MHz ?

the LF411cn jfet op-amp with a bandwith of 4Mhz ?
exept the op-amp most are negative voltages.
the op-amp is just a buffer,?

LC-Osc.
http://en.wikipedia.org/wiki/LC_oscillator


f= 200MHz
L=?
C=?

Why a XO if has an LC_?

Logic would be the Schmitt for cleaning up the clock, and dividing for a lower frequency... but the L301 does not fit in the equation.

[AngeloGomes]

Hi Guys, I have a SR850 and the circuitry for the CRT is the same.

My Sr850 CRT is passing away and  I am wondering how to replace it by a LCD display.

Can someone give some advice about how to do it?

[free_electron]

these things are simple MDA monitors.