If this is in the wrong area, please let me know / move the thread.
I have a circa 1980's Audio Analyzer - unfortunately I do not have the custom CRT that you could purchase back then. I thought I could just get a bunch of adapters and hook it to a modern LCD, but that is not working.
What I am hoping to do is find out if the unit is putting out a decent video signal. I have access to an oscilloscope / DMM and will look for a CRT tomorrow. However, I have to make a decision soon on whether to keep / return it - so hoping to find out if the video signal is _clearly_ broken before I go and purchase a CRT that may/may not work with this unit.
So I want to test the pins on the monitor plug and determine if they are providing a good signal. The device turns on, fan starts, I can detect voltage on the various internal cards. Inside the computer there are 3 pins that go from the "Graphics card" to a DB-15 plug.
http://i.imgur.com/kG3yyLH.jpg
These 3 wires to go a DB15 plug on the back of the computer labeled CRT MONITOR.
When I attach my DMM ( 388-HD ) to the 3 pins that are attached to the card, I get:
PIN1: .3VAC (.06VDC ) .120 Khz
PIN2: .03VAC (.00VDC )
PIN3: .04VAC (.00VDC )
I have not tested with my oscope yet - I am going to do that this evening.
1) What would appropriate voltages be?
2) Am I able to measure these using my DMM ( I read that low HZ signals could be problematic )
3) Aside from plugging in a matching CRT, is there anyway to determine some basic level of functionality?
A manual for a similar unit ( the 201 ) which comes with a built in CRT says it operates at 50hz, which surprised me.. I figured it would be one of the 15hz types.
Any help appreciated!