Today’s quick teardown target is a 1985 vintage electronic load made by Kikusui of Japan. It came from eBay with a noisy fan, but was otherwise fairly functional despite the considerable age.
Only 2 inches wide
The load offers quite a nice set of features, all without using a microcontroller.
- Constant current and constant resistance modes
- 4-110V input range up to 12A
- 12A and 1.2A range
- Two independently settable current levels with pulse ability (1kHz and 100 Hz)
- Current monitoring output for scope connection
Being purely analog, no serial interfaces are available. Instead the load takes voltage and resistance control signal via terminals on the back. Opening the lid brings us a very tightly packed unit:
Very compact and tightly packed design. Fan removed for replacement
Massive heatsink and cables galore
Current sense resistor
Thermostat
Power BJT transistors by SanKen are behind this board
Power BJT
1985 datecodes
Input leads soldered straight to screw terminals
Wires everywhere
For those interested, user manual is here. The load is very compact and handy, especially for those with small desks. The exposed high voltage leads on the transformer made me want to put a sheet of isolating material on the inside the case opposite of them, just in case. At least the case is grounded…
Just FYI it’s Kikusui, not Kukusui…
Indeed- fixed!
Thanks for pointing that out
What fan did you replace it with? I have the same unit with a noisy fan that I would like to replace.
Thanks.
If my records are correct, I used NMB 2412PS-12W-B30. It’s a a current model,but 115VAC version. It ends up running a bit slower on a 100V transformer winding, but oh well
Hello,
Kikusui PLZ 72W can work at 220 V ? (Europe)
If yes can you tell how to change power input setting ?
User manual seems to indicate 120V only (108-132V AC to be precise)
Telonic in the UK have been selling Kikusui loads for years.
https://www.telonic.co.uk/All-Electronic-loads-s/1846.htm
Might be worth giving them a shout.