repairing a DEC VT420

Hi, I bought a VT420 from a neighborhood garage sale ($5) that turned out not to work. Turn it on and I saw nothing happening. Only heared a faint "fip ... fip ... fip ..." kind of sound, you know that one "fip" when a screen comes on, just a little softer and repeated about 1 per second and no screen came on. Opened the box and powered on, the kathode in the tube didn't seem to glow. More inspection turned out that what seems like a ceramic capacitor was exploded or fried, all black and crummy, impossible for me to identify its specs. Can someone help me out with a schematics or databook or something? Again the terminal is DEC VT420 the blown-up capacitor is C621. What kind of collateral damage do I have to expect? I mean, does a fried capacitor normaly cut short? Here are some hints: - That C621 is in close proximity to C617, another sizeable capacitor. However there are no marks left on that one after cleaning the explosion site :-) - A diode D603 is also in that neighborhood, doesn't look bad, but I didn't test it yet. - I do see suspicious brown-coloration in an area farther off around D607 and R649. I wouldn't be surprized if R649 was fried. - R650 is in next to R649 but looks fine to me, though I didn't test it. It's always a problem to test components while in the circuit, don't know what I should expect. I appreciate any help. thanks, -Gunther -- Gunther Schadow, M.D., Ph.D. gschadow(a)regenstrief.org Medical Information Scientist Regenstrief Institute for Health Care Adjunct Assistant Professor Indiana University School of Medicine tel:1(317)630-7960 http://aurora.regenstrief.org