HP-35 Power Supply Waveforms

[teenix]

(04-06-2019 08:59 AM)albertofenini Wrote:  With a Vbatt of 3,94 Volts this is what we get
Vcc : 9,67
Vss : 7,21
Vgg : -15,47

Much better that the previous, but still too high, I would not power a calc with these.
The Transistors are original (0550 and 0094), the 2,2nF, the 22microF and the 60microF capacitors are originals and so is the Toroid.
Resistors are a mix of new and original, but all of the exact (measured) value
Diodes, Zener and smaller capacitors are new, of very close value to the original ones.
We may try to find a zener with even a lower value or harvest one from a donor and see how it change,
what do you think ?
Thanks and take care !

Not sure what value zener diode you are using, but maybe try a 5.6V or 6V or 6.2V, 500mW. They are all cheap to buy.

cheers

Tony