Great, my VT52 is shot.

Ok, some test results below. 1) Are we sure J2-2 should be -12? It really seems to like being -15. 2) The voltage across the zener diode there is a nice solid -3.8-3.9v. It appears to be a germanium diode (.1v drop across, both directions) I could disconnect it and see if that makes things better. 3) E2.3 is -22mv referenced to ground E2.6 is around .6v. Ramps up from about .58 at startup to .61 then down to .60something. Note that is a positive voltage wrt ground. Q12 was reading -24.4v emitter -15v collector -23.8v base Q12 does not have a CE short What is this using as a reference to get the -12v from the transistor? Maybe the zener is just out of spec. Can someone with a VT52 cross check my voltages to see if they are accurate? Thanks all! > E2.6 I expect would normally be within +/- 2V of GND. > If E2.6 is way-positive (>Q4.E, > ~ +2.6V), then E2 is attempting to > throttle down the output but failing due to some failure around Q4/Q12. > > Measure the voltages on Q4 and Q12. > They could be leaky or low-gain. > It's conceivable Q12 has a CE short, but I'd expect the input to the > reg to be more than -15. > > The low -5 is odd, zener D14 looks to be a 5.1V type. > R45 is probably burning up. > I haven't spotted anything in the schematic that actually uses the -5, > it looks to be provided for some alternative character generator > (schematic pdf.42), > so that may depend on what character generator chip / daughter board > is used in your unit. >