[old_tv_nut]

The tolerance on electrolytic capacitors for TVs and radios is usually much larger than 20% on the plus side. Typical consumer parts tolerance would be -20/+80%. Usually the only concern in design was that it not vary too much on the low side, which would increase hum. So, even if the originals were oversize, I think 47 uF will be fine to replace the 50s, especially if you use tighter tolerance units, like +/- 20%.

The 20MFD@25v should be replaced with something closer to both its specified capacitance and voltage (but not lower).