5 replies to this topic

[boxpressed]

I think it's time for me to invest in a quality multimeter to help troubleshoot some current issues and in anticipation of future ones. First off, can anyone recommend a good one that won't break the bank?

Second, how do you do it? For a Colecovision PS, it is as easy as plugging in the PS, setting the multimeter to "voltage," and touching the black probe to ground and then using the red probe to test the other pins?

How would you test a PS that has only one "pin" -- such as a 2600 PS or an A8 PS? Thanks in advance for any advice.

[nathanallan]

When you say touch to ground, do you mean as it's plugged in and turned on? I normally use a WaveTek, they're pretty inexpensive, here's one that will fit the bill:

http://rover.ebay.co...r=sbar&_lwgsi=y

Not too expensive and capable at the same time. They are not much more brand new.

To properly test a power supply it has to be tested under its normal load or a similar load, such as inside the case (speaking of a 2600) or the board outside the case with a game in and also controllers and RF cable hooked up. Same as you described, center positive pole to red and then ground of the device.

If you test it by itself it'll give you an unloaded result, which might not be accurate as far as it working correctly or not.

[Zach]

We use a Sinometer MAS830B in my class. Someone with more experience than I decided on that model.

[Rybags]

For simple voltage testing even a $5 MM would be practically as good as a $300 one.

You only really need accuracy to .1 Volt when checking what's being put out.

In the cases you can't test under normal load e.g. don't want to risk your gear, you could simulate the load by using light bulbs or something else that draws about 70-90% of what the PS should be rated to.

The cheap rotary dial MMs are OK, they seem to vary a bit in what functions they provide.

A handy function is the continuity test with the beep - you can test for solder bridges or a good circuit quickly by touching 2 points, the beep tells you that the 2 points are joined.

[boxpressed]

This is all very helpful information, thank you. I forgot about testing under a regular load. So here's the noob question: let's say that I plug in a unit and cartridge to test. Where would I put the probes to test?

[Stephen Moss]

It depends on which supply you are testing...
If testing the main power brick then on the PCB at the power connector would be the obvious place although that will probably mean removing the PCB to get to the under side.
If testing the VCS's internal regualted +5V supply and you don't have a circuit diagram find a standard logic device which should have a four digit number printed on the top staring with 74, i.e. 7400 or 7414. When you find one located at one end should be a semi-circular notch or circular indentation. With that end furthest from you the power pins will be 0V bottom left and +5V top right.

Additionally although the DC power connector used on a 2600 may be single pin as you call it there are none the less two terminals (the inside and outside) although I cannot rember the polarity off hand.