I'm working on an Eico ST96 tuner and have found what appear to be a number of errors in the instruction manual.
To begin with, in the tube pin voltage test chart, the manual states .62V for pin 6 of V8 which is a 6BE6. This is the screen grid pair (pentagrid mixer) and should thus have a high voltage. I'm guessing they meant 62V. My tuner measures 53V at this point.
Next I found was specification of 73V for pin 6 and 116V for pin 5 of V4, a 6AU6. Pin 6 is screen grid and is connected to the final FM IF transformer primary along with that stage's own bypassed supply (10k into 4.7nF). Pin 5 is the plate and is connected to the other end of said primary winding. Unless the resistance of the IF transformer primary is very high, these voltage specifications should be about the same. It is no coincidence that the manual states matching voltages for the screen and plate of V3 and V2, the previous FM IF stages. My tuner measures 56V at both pins 5 and 6.
I should mention this tuner is functional.
Other than that, things seem to be okay but I wouldn't be surprised to find other errors. I just wonder if others have noticed errors like this in Eico manuals?
To begin with, in the tube pin voltage test chart, the manual states .62V for pin 6 of V8 which is a 6BE6. This is the screen grid pair (pentagrid mixer) and should thus have a high voltage. I'm guessing they meant 62V. My tuner measures 53V at this point.
Next I found was specification of 73V for pin 6 and 116V for pin 5 of V4, a 6AU6. Pin 6 is screen grid and is connected to the final FM IF transformer primary along with that stage's own bypassed supply (10k into 4.7nF). Pin 5 is the plate and is connected to the other end of said primary winding. Unless the resistance of the IF transformer primary is very high, these voltage specifications should be about the same. It is no coincidence that the manual states matching voltages for the screen and plate of V3 and V2, the previous FM IF stages. My tuner measures 56V at both pins 5 and 6.
I should mention this tuner is functional.
Other than that, things seem to be okay but I wouldn't be surprised to find other errors. I just wonder if others have noticed errors like this in Eico manuals?
Found another significant error in the manual.
The page 10 Fig.6 labelled picture of the underside of the chassis lists both the loopstick and the local AM oscillator coil as L1. In fact the loopstick is L1 and the LO OSC. is L2.
Page 9 Fig.3 of just the circuit boards does not have this error.
The page 10 Fig.6 labelled picture of the underside of the chassis lists both the loopstick and the local AM oscillator coil as L1. In fact the loopstick is L1 and the LO OSC. is L2.
Page 9 Fig.3 of just the circuit boards does not have this error.
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