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Tenma DMM Drivers & PC Software

My new DMM I posted about a while back came with PC software & drivers for the RS-232 interface, on a CD. I haven’t used CDs for some time, so I had to dig out my USB drive.

The Tenma website doesn’t list the software for all their models, so to help others I’m posting an archive of all the supplied drivers here. The archive contains software & drivers for the following Tenma models:

Tenma Multimeter Drivers (783 downloads)

Tenma 72-1015
Tenma 72-1016
Tenma 72-1020
Tenma 72-2610
Tenma 72-2620
Tenma 72-7712
Tenma 72-7715
Tenma 72-7730
Tenma 72-7730A
Tenma 72-7732
Tenma 72-7732A
Tenma 72-7735
Tenma 72-7745
Tenma 72-7750
Tenma 72-7755
Tenma 72-7760
Tenma 72-7790
Tenma 72-8400
Tenma 72-8720
Tenma 72-9280
Tenma 72-9380
Tenma 72-9380A
Tenma 72-9405
Tenma 72-9490
Tenma 72-10405
Tenma 72-10410
Tenma 72-10415
Tenma 72-10440
Tenma 72-10445
Tenma 72-10465

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IC Decap: ITE IT8712F Super I/O Controller

IT8712F Package
IT8712F Package

These chips are used on PC motherboards, to control many of the legacy peripherals & things such as temperature monitoring & fan speed control.

Here’s the block diagram from the datasheet to show all the features, this IC handles many things on a modern motherboard!

Block Diagram
Block Diagram
IT8712F Die
IT8712F Die
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DIY SMPS Fan Controller

Now the controllers have arrived, I can rejig the supplies to have proper thermal control on their cooling.

Changes Overview
Changes Overview

Here’s the top off the PSU. The board has been added to the back panel, getting it’s 12v supply from the cable that originally fed the fan directly. Luckily there was just enough length on the temperature probe to fit it to the output rectifier heatsink without modification.

To connect to the standard 4-pin headers on the controller, I’ve spliced on a PC fan extension cable, as these fans spent their previous lives in servers, with odd custom connectors.

Fan Controller
Fan Controller

Here’s the controller itself, the temperature probe is inserted between the main transformer & the rectifier heatsink.
I’ve set the controller to start accelerating the fan at 50°C, with full speed at 70°C.

Full Load Test
Full Load Test

Under a full load test for 1 hour, the fan didn’t even speed up past about 40% of full power. The very high airflow from these fans is doing an excellent job of keeping the supply cool. Previously the entire case was very hot to the touch, now everything is cool & just a hint of warm air exits the vents. As the fan never runs at full speed, the noise isn’t too deafening, and immediately spools back down to minimum power when the load is removed.