Sales update

January 22nd, 2018

22 Jan 2018


MOSFET: Toshiba 2SK1530-Y/2sJ201-Y pairs for sales:

NNN-PPP 3 pairs, match NNN and PPP only: HK$600.  AVAILABLE

NNNN-PPPP 4 pairs, match NNNN and PPPP only: HK$800. AVAILABLE

Note that there is no NP match but those order early may have Limited stock!



Toshiba K170BL – only 6.5mA to 9mA (HK$100 for 4 pcs)

Toshiba J74BL – 6.4 to 10mA (HK$110 each pc); >10.5 to 11.2mA (HKD$75 each pc)

Toshiba K170 / J74 pair HK$150 each pair (6.8 to 10mA).  Limited stock!

Note all jfets can be matched to maximum 4 pcs in one group of same channel type.  Example NNNN, PPPP, NNPP, and NNNNPPPP.  All within 0.2mA Idss tolerance.

Thank you for all the support! 

Due to my daytime job and out of country most of my time, I can only ship once a month.  Please email to me for any inquiry.

hp 5334A Frequency Counter 100MHz

July 23rd, 2017

Pick up this in junk yard for a low price and found inside all corrosive due to battery leakage!  After I do a cleaning and washing on the main PCB and replace all 6 pcs 100uF 15V cap with new Panasonic FC capacitors,  the set can work as it is.  Gone through performance check and all ok, self diagnostic also all OK, frequency can measure up to 105 MHz and level down to 35mVpp which is a bit better than spec.  Date code of part is mostly at year 1986, this this is a 30 years old hp equipment and is still working fine!  Made in USA.


Leader 1507A Repair (3-51FT-A Replacement)

July 1st, 2017

This digital signal generator was stored for too long time and the internal battery was leaking and corroded the PCB near by.  After removing the battery (Nicad 3-51FT-A) and cleaning the PCB, power on test show that there was no display on the front panel.  One 1k resistors was also replaced in the charging circuit and put back a 3.7V 110mAh Ni-Polymer rechargeable battery, but the set still could not power on.  Note that the battery was got from ebay China seller with only SGD$0.9 and free shipping!  It is a 110mAh capacity and the original batter is 80mAh capacity.

After measuring the rail voltage, it was find that the two 5V supply after the regulator JRC 7805A was not at normal voltage, one close to zero and another one 4.5Vdc. Replacing the two regulators with Toshiba 7805S regulator and the set is back to normal.  Here are some photos for the repaired set.

NI PXIe-8370, PCIe-8371, PXI-GPIB upgrade

November 26th, 2016

I was using NI PXIe-8105 embedded controller in my NI PXIe-1062Q chassis but the speed is too slow.  Recently I have acquired the controller card PXIe-8370 (about 800MB/s; pcie x 4).  The PCIe-8371 card can be put  in my computer PCIe x 16 slot (for VGA card) and function perfectly. Mother Board is Gigabyte H77N ITX version. OS is WIN7 64bit version and both the NI and audio precision system two cascade is working fine with an I5-3570K CPU.  The fan noise of the NI chassis is even lower then before and the power loading is lesser without the embedded controller!


Without the embedded controller, I lost some I/O like parallel port, GPIB etc… and thus I have to get one more PXI-GPIB card.  Later I find out my Agilent 82357B USB – GPIB controller is also working fine in with NI system.  In the past, I plug the USB into PXIe-8105 but cannot make it work properly!  Thus the PXI-GPIB card become excess!

Key sight DSO-X 3024T firmware update

November 25th, 2016

Update: 3rd July, 2017

Further updated firmware to 07.11.2017061225 version.

Keysight has released new firmware 04.08 for DSO-X 3024T and here are the photos of upgrade process.  The whole process take about 5-6 mins.