Tektronix oscilloscope showing sin wave but outputting constant value

Question

I have two Tektronix oscilloscopes:

scope 1: MDO34

scope 2: MDO4104C

I am running this code to get data from them:

def acquire_waveform(self, channel: str, recordlength: int=1000):
    """Get waveform data from channel

    Args:
        channel (str): Channel you want to get data from, default: CH1

    Return: list of waveform data in format (Time,Volts)
    """

    # set up
    self.write('ACQUIRE:STATE OFF')
    self.write(f'SELECT:{channel} ON')
    self.write(f'HORIZONTAL:RECORDLENGTH {recordlength}')
    self.write('ACQ:STOPAFTER RUNSTOP')

    # acquire waveform data
    self.write('ACQUIRE:STATE ON')
    self.write('DATA:SOURCE ' + channel)
    self.write('DATA WIDTH 1')
    self.write('DATA:ENC RPB')
    ymult = float(self.visa.query('WFMPRE:YMULT?'))
    yzero = float(self.visa.query('WFMPRE:YZERO?'))
    yoff = float(self.visa.query('WFMPRE:YOFF?'))
    xincr = float(self.visa.query('WFMPRE:XINCR?'))
    xdelay = float(self.visa.query('HORizontal:POSition?'))
    self.write('CURVE?')
    data = self.visa.read_raw()
    headerlen = 2 + int(data[1])
    header = data[:headerlen]
    ADC_wave = data[headerlen:-1]
    ADC_wave = np.array(unpack('%sB' % len(ADC_wave),ADC_wave))
    Volts = (ADC_wave - yoff) * ymult  + yzero
    Time = np.arange(0, (xincr * len(Volts)), xincr)
    return Time, Volts

When I do this for scope 1, I get the expected data. On scope 2, I get a constant value of about -2.52 V. Both scopes are displaying the data properly and are set up/triggering in the same way.

Ive tried using the MEAS:IMMED function and it seems to be able to measure things on the scope, but waveform data isn't being output how I expect it.

I am trying to acquire data from CH2.

This is the setup I'm using:

# HORIZONTAL
oscilloscope.write([
    'HORizontal:RECOrdlength 1000000',
    'HORIZONTAL:DELAY:MODE OFF',
    'HORIZONTAL:POSITION 50',
], 'Set scope horizonal record length, delay, and position')

# Scope CH1
oscilloscope.write([
    'CH1:BANdwidth FULl',
    'CH1:COUPLING DC',
    'CH1:TERMINATION MEG',
    'CH1:SCALE 0.5',
    'CH1:OFFSET 0.0',
    'CH1:POSITION 0',
    'SELECT:CH1 ON',
], 'Setup scope CH1')


# CH2
oscilloscope.write([
    'CH2:BANdwidthFULl',
    'CH2:COUPLING DC',
    'CH2:TERMINATION MEG',
    'CH2:SCALE 0.5',
    'CH2:OFFSET 0.0',
    'CH2:POSITION 0',
    'SELECT:CH2 ON',
], 'Setup scope CH2')


# TRIGGER
oscilloscope.write([
    'TRIGGER:A:EDGE:SOURCE CH1',
    'TRIGGER:A:EDGE:SLOPE RISE',
    'TRIGGER:A:TYPE EDGE',
    'TRIGGER:A:LEVEL:CH1 0e0',
    'TRIGGER:A:MODE AUTO',
], 'Setup scope trigger for CH1 edge, auto')

# Horizontal for a few RF cycles
oscilloscope.write([
    'HORIZONTAL:POSITION 50',
    'HORIZONTAL:SCALE 40E-9',
], 'Setup scope horizontal for a few cycles')

# Acquire
oscilloscope.write([
    'ACQUIRE:MODE SAMPLE',
    'ACQUIRE:STOPAFTER RUNSTOP',
    'ACQUIRE:STATE RUN',
], 'Setup scope acquire and run')