Off beam values Hackers?

[boater sam]

Fixing Hackers is fun but why did they use such odd values of electrolytic capacitors?

Example, the 205 amplifier pcb uses 80uf (2 in parallel), 6.4uf, 40uf and 400uf. None of these are present day standard values.
Is it a supply situation or deliberate act to use unpopular values?
I substitute the closest values from stock, 100uf, 10uf, 47uf and 470uf. With the wider tolerances these seem close enough.

[Mike Watterson]

Most older electrolytics are +80% & -20% tolerance and in most applications even wider tolerance is OK. Except valve rectifiers have a maximum loading and best to have about x2 rating vs actual no load voltage.

2, 4,  6.4, 20, 32, 40, 64 and 80 used to be common. See also resistors
Now replaced by
2.2, 4.7, 22, 33, 47, 68 and 100
From
1.0, 1.5, 2.2, 3.3, 4.7, 6.8 (E6)
Only more precise tolerance capacitors use E12
1.0, 1.2, 1.5, 1.8, 2.2, 2.7, 3.3, 3.9, 4.7, 5.6, 6.8, 8.2,

So you'd only replace a non-electrolytic 4uF (maybe in an audio filter) with 3.9 as 4 + 80% = 7.2uF! Otherwise 4.7 is fine.
80uF + 80% = 144 uF, so 100uF is fine



Resistors were first to use E series (History of E series)