Author Topic: System 80 Driver Board / Gottlieb Q's  (Read 1391 times)

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Offline MartyJ

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Re: System 80 Driver Board / Gottlieb Q's
« Reply #30 on: May 04, 2009, 09:18:48 PM »
You dont need to go splashing big bucks on a Fluke just to test a simple transistor. - Also just cos its a DMM and nice and modern doesnt also mean that it makes your life simpler. I hate DMM's unless reading a voltage as the correction factor due to internal resistance is minimal.
 Go spend $40 on an ANALOGUE meter. Set it to Ohms. Put leads on E and C on your transistor - any reading and its stuffed.

E to B should read high with leads one way and low with them swapped around - same with C to B.

In other words you have a "gate" that only allows a flow of electrons one way, if you get the same readings with the indicator sweep on the meter with red and black leads swapped then your "gate" is stuffed and so is your transistor.

Its by far the easiest way i know to test a transistor. DMM's are a pain in the butt

An analogue meter is no doubt a lot cheaper and for someone with a good foundation in electronics would be the best option.  Unfortunately for me, I'm still very much a noob in this area.  I can repair and my solder skills I would now rate as above average, but I still lack the basic knowledge of how and why things work.  When my year frees up a bit I'm still planning on trying to get a basic electronics course under my belt, along with an airbrushing course too!
I can follow the PinRepair guides now from start to finish, compare readings and replace whats broke.  Unforuntately I think a DMM would be a better option whilst I'm still noobing.
The problem with my existing DMM is that due to its faulty readings, I nearly went out and purchased a NOS driver board (but Dave came to the rescue!)...But still I don't want this problem to occur again as I will definately be doing more repairs in the months, weeks, years to come.
I can go out and buy another DMM from DSE/Jaycar etc...for $50 to $100 but the one common thing a lot of people are saying is buy a Fluke.  If there is an intermediatery DMM - ie between a chinese cheapo and a Fluke, I would be interested.  I'm not a professional so the top shelf stuff is not required, but I don't want a 'my first multimeter' either!