FET Audio | Hi-End Audio & Electronics DIY Electronics & Repair

These were newly acquired in Nov 2015 from eBay.

PXIe-1062Q: for both PXI and PXIe cards with power supply.

PXIe-8105: controller for the system with upgrade to IDE 120 GB SSD from Kingspec (China) and 4 GB (2 x 2GB) DDR2 RAM.  Actually I found all on hand DDR2 ram with higher speed with work on this controller.  BIOS has also been updated to the latest version 1.3.3.  Speed wise is ok fast now with SSD and 4GB ram under window 7 32bit.

PXI-4130: SMU with two output: +/-20V max 2A and 9V 1A.  This supply can be programmed to check transistors or FETs under Labview.

The total cost is about USD$1500 but if getting a SMU with dual output will be much more expensive!

I shall learn and try to develop a program to sort the mosfet 2SK1530 / 2SJ201 soon.  Sorting of the Toshiba 2SK170 / J74 is also very good as the speed is supper fast and reading is stable with no oscillation concern.

USB GPIB adaptor 82357B from Agilent has big issue to link up with other equipment on the NI controller even I follow the steps as what is advised by Aglient website.  Finally I get the original NI GPIB cable Type X13 183285-02 and every things works perfectly.  No wonder the price of second hand USB-GPIB cable from Agilent is half of that from NI!

Changing the 3V back up battery in the PXIe-8105 controller must need reset the reset jumper pins or else the controller cannot boot up at all.

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This scope failed 3 years ago and the symptom was just no display after power on but some LEDs flicks to a point and stopped at “ADD” LED there!  Recently I take it out and attempt to repair it.

The first suspect is the high voltage board defective and I open it and do a check on the high voltage board switching transistor and everything looks fine.  Also I can get about 65k switching frequency at the switch mode power supply.  After looking around, I see there is a “G Bias” pot on the high voltage board and then I turn it clockwise and see some display DOT on the screen.  The scope wordings of time base and input attention can be seen also.  Thus I reboot it and see a “Step 05 fail 44” error on the screen.  After checking the service manual it point to the DAC on the control board and thus I look at it again.  Oh I find the leaking SMD capacitors with corrosion in its surrounding components.

It can be seen that the components surrounding the three E-cap are with corrosion solder join!  So in totally changed all 4 SMD e-caps on the control board as the other corner also have one more leakage e-cap.

After changed the 4 caps, I put back the board and power on the set but the failure symptom is still same step 05 fail 44!!!  So I probe around the DAC chip and check the Vref 10V at pins 14 and pin 15.  The voltage is really low and close to 0 volt.

So I started to check the components around the DAC U2234 and later find out that the resistor R2228 10k is open circuit.  I replace it with another one smd resistor and after that I power up the set and it works again!

I burn in the set for about 15 mins and then I start to smell something from the scope and of course power off it immediately.  Open up and found the line filter caps (RIFA) brands are all burnt together with two more resistors.

C1018, R1018, C1016, R1010 (parallel with RT1010; 15 ohm not on schematic) were all burnt of open circuits.  Later I also find three more Rifa capacitors on the other PCB (2200pf and 10nF 250v ~ is also crack a bit on the body.  I take them out and all the 2200 pf caps are with very low value of about 100pf!  Thus I order them from element14 and they arrive after 3 days.  For the 0.068u 250V~ cap, I use on hand 0.1uf 250V~ cap to replace them (blue color on the picture).  After put back, everything  works fine.  I have brought this 25 years old scope back to life!

I also note that there are many same scope 2445 or 2445B with similar failure of step 05 fail 44.  I hope this information can help some of the people to repair their scope.

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I acquired this machine for a month from Seagate Singapore but this set do not have the JTA software option for jitter measurement.  I have asked Lecroy for the cost of JTA option but they want to charge me 5k USD ! Anyway DDA-120 is for disk drive analysis and it has a simple jitter measurement using period@level function.  Also it has period, frequency, sigma and histogram function which is good enough to do some clock signal jitter measurment as below:

 I have also taken some measurements of DAC chips as in attached file.  They are WM8804, CS8416, DIR9001; SRC: CS8421, SRC4192 & AD1896.  The measurement is on the MCLK (master clock) of the DAC FDA-1 in different test version durng development.

Jitter Measurement

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This is a very old machine used for automatic tester with HPIB control capability.  There is some very good old transistors as shown.  The transformer is still EI type and thus the set very heavy even the size is not big!  The bad thing about this supply is too noisy for lab use due to fan noise.  But it is a very low noise and high speed power supply from 0 to 20V and 5A maximum.  If you want to change the input AC voltage, you have to open the set and select by two switches near the IEC socket.

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I acquired this function generator in Oct 2011 and here is some internal photos to share.  My set is with the internal 10Mhz reference oscillator option.

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