3 PIN CDI Different Component?

[Alfasrule]

Receive 2 Units from an Alfisti to recondition them. I took the 1st one apart and I noticed it was repaired, and it had a different component ZD1. I just thought it was just a 5W instead of a 10W. So I ordered the correct component. Yesterday I finally got the other Unit apart and the same exact change was installed on this Unit as well. These changes were made some years ago. The device in both is quite different than the one called out in the schematic. The schematic calls out a 82V 10W Zener Diode. The device installed in these Units is a TransZorb Transient Voltage Suppressor? Been doing electronics for over 30 years first time. I want to see how this works verses the Zener Diode. Reading the data sheet it should work better since it fires for a set time. 1N6293
http://www.goodark.com/datasheet/transient_voltage_suppressors/transient_voltage_suppressors/1N6267-1N6303A.pdf

Has this been done by anyone?

[HawgRyder]

Any component that would restrict the voltage to 82V should work.
The only thing that might be a problem would be leakage below the 82V threshold.
I suppose an MOV would work too if you could get one to fire at 82V +/- 2V .
The whole idea is to prevent the CDI generated high voltage pulse from backing up into the 12V power line.
Bob

[mysocal911]

Originally Posted by HawgRyder

The whole idea is to prevent the CDI generated high voltage pulse from backing up into the 12V power line.
Bob

Actually, the purpose is to limit the maximum voltage the switching transistor 'sees'.

[HawgRyder]

Ooops...sorry...you are correct...My brain froze for a minute.
The idea remains the same....but in a case of power to the transistor...only a one way limiting device will work.
Technology has come a long way since these boxes were designed...and components have changed a lot....so a Zener (82V 10W) could be smaller and more robust now.
My personal look on things...I usually replace components with better parts...so by all means...82V...but perhaps a 25W unit instead.
I tend to over repair things...my own CDI had a 40Amp SCR placed in it...instead of the 6Amp.
They were the same size, so why not?
Also...the new SCR was rated at several hundred volts higher.
Bob

[Alfasrule]

The Zener is the same as the old one physically and it costs over $16.00. The 1N6293 is much smaller and easier to install and costs less than a dollar. I will get this unit working this weekend and compare the signals of the 2 different versions of this circuit. I already have the signals stored from a Unit with the original components installed. I will post the results.