> no sound
*NO* sound at ALL? Or faint hum/hiss with no guitar? Big difference.
> On a couple of the pots the whole shaft pulls out. Would that cause the signal to stop?
A Volume pot, turned full-down, sure should 'stop signal'. Push the shafts back in and turn the pots half-up. That should pass sound. Unless the shaft-break also shattered the internal resistor wafer. You can jumper-around this guy's Volume pots. The bass/treb pots, busted, may give odd tone but not "no sound".
> The pilot light comes on but no sound. Any ideas where to find a schematic, and how to troubleshoot?
Car lights work but engine won't start.
Don't REALLY need a schematic to troubleshoot a car with a major problem. Some systems "just have to be" and the general symptoms don't need brand/model details.
If the car won't crank, there's a couple big wires and a little relay. You expect to find 12V a bunch of places.
If the car cranks but won't cough, you check fuel and sparks. In old days we'd pull the hose off the carb and see if gas ran out. (Don't try this on modern non-carb cars.) Also pull a spark wire and see if the sparks are happening (again, modern cars foil us; but a Neptune City DanE ain't modern.)
You want to work inside the chassis. *You can get killed in there!!* Read good tube amp safety instructions.
I would check the speaker first. Does the Ohm-Meter say 6 Ohms? If you carefully clip-lead it to your testbench amp's speaker, does sound come out? A dead speaker explains all the symptoms.
So does an un-plugged speaker. (I wonder how I know this?)
After verifying that sound could come out, I'd go for B+. Like if a car battery isn't 12V, there is A Problem. We know that tube-amps generally have B+ of 250V to 600V (so be *careful!!*). The 7189 tell me guy aimed for 400V (however the plan shows 7189 under-run at 310V, you could have run 6BQ5/EL84 in this, maybe 7189 were on-sale that month). There's a wire from the rectifier to a filter-cap (a multi-cap can in this plan). *Carefully* clip your DC volt-meter to ground and that cap. Stand back. Power-on. Watch the meter. We'd expect it to stay low while the rectifier warms up, maybe go high, then fall as the power tubes warm up. Without the plan, I'd be looking for 400V, but 310V would not be "wrong", and the plan says it is right. 100V or zero would be wrong. This points to PT, rectifier, or a short on the B+ (and if you've had it powered-up a while, you'd know if it was shorted).
The pilot light on the plan is across the 110V wall-voltage. It tells you the power switch and main fuse are good, nothing more.
PLEASE convert the power-cord to 3-pin and clip-out the ground-flip cap. When AOK, wrong flip gives a strong tingle which you probably survive. When 50 years old, that cap could be dead-short and flow "infinite" current through you to ground.
Topic: Danelectro DX-250, not working (Read 3982 times)