OK but, don't go ripping stuff out willy-nilly. Lets see if we can get a handle on what's going on first.Ah ha! The Marantz 2250 has the same SV-3A's
It's now early evening here so I am off out. Back on it tomorrow.
OK but, don't go ripping stuff out willy-nilly. Lets see if we can get a handle on what's going on first.Ah ha! The Marantz 2250 has the same SV-3A's
OK but, don't go ripping stuff out willy-nilly. Lets see if we can get a handle on what's going on first.
It's now early evening here so I am off out. Back on it tomorrow.
If you can get to the bases of H611 and H613, put you dmm on those points and measure the voltage. It should be close to four Vbe's or 2.4V. Maybe a little more or a little less but not substantially so.
I would next measure the voltages at the base of H615 and H617.
With power back on, measure the voltage at H603 emitter.
With power off, measure the combined in-circuit resistance of R627||H605. Try it with the meter leads one way, then switch them and measure again. Do this with R627 at both extremes of rotation.
Base to base:
H615 to H617 = 1.88V
H616 to H618 = 2.02V
I should have specified where to set the pot for this measurement. Please try it with the pot set to maximum resistance.
All the voltages listed in your drawing are within reason, if a little high. The one exception is the half a volt on H617 & H618 measures closer to 1.5VTo hopefully improve clarity, this is the DC circuit we are looking at:
R621 doesn't appear damaged or anything. Brown, Black, Brown, Gold = 100 ohms. Tests at 101.5 ohms. It's counterpart at 99.5 ohms.Does R621 *look* OK? The voltage drop across R623/R625 is about a volt less than it should be. The voltage drop across H701/H605/R627 is lower than it should be. That all points to the current through this series section is too low.
Yet the 0.6 volts at the emitter of H603 would indicate there is 6 mA - as long as the emitter resistor is indeed 100 ohms.
The voltage at J605 is 49.6V if that's what you mean.Have we measured the 50 volt buss yet?
As I adjust it, the waveform appears to smooth out a little, then goes back. I get the same result no matter which way I adjust itHave we measured the 50 volt buss yet? Have you tried adjusting R615 toward a lower resistance, raising the base voltage (and emitter voltage hence current) of H603?
the half a volt on H617 & H618 measures closer to 1.5V
YesDo we also have 1.5 volts to ground on J612 and J614?
YesHow about on the bases of H002 and H003?
These are at zeroCan you measure a voltage at the emitters of H002 or H003? Those *should* be at ground potential.
At first I was like "there's no way", but the more I look at the schematic, the less I understand what pins jumper to where. For example, what pin does the collector of H001 go to?Any chance you got the base and emitter connections of H002 and H003 reversed?