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

July 1, 2017

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

Filed under: Test Equipment — Spencer @ 4:34 pm

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.

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November 26, 2016

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

Filed under: Test Equipment — Spencer @ 12:13 am

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!

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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!

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November 25, 2016

Keysight DSO-X 3024T firmware update

Filed under: Test Equipment — Spencer @ 11:56 pm

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.

 

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November 19, 2016

Audio Precision USB APIB Adapter (inside photos)

Filed under: Test Equipment — Spencer @ 11:05 pm

I am using PCMCIA to APIB to control my AP system two cascade under winxp.  The PC is celeron with PCMCIA slot and thus is running very slow.  One way is to use a PCI to PCMCIA adapter if PC is to be upgraded.  I just have one i5  – 3570K with 8GB ram and ITX Mother Board and thus no PCI slot!

Recently I saw a old AP USB to APIB adapter on ebay for about US$350 and thus I think it is time to upgrade the speed of the AP system. 

Here is some photos inside the adapter.

USB interface – Cypress CY7C68014A-128AXC

74ATC240 / 74ACT245

4420P-G01 / 4816P 

See photos for details.

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November 6, 2016

Ekras distribution amplifier inside photo

Filed under: Other Amplifiers — Spencer @ 12:18 pm

This is Korean distribution power amp and record some photos before throw away.

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