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HP-35 Power Supply Waveforms
04-03-2019, 10:26 PM
Post: #12
RE: HP-35 Power Supply Waveforms
We re-designed the circuit on a different breadboard using the same components.
At the beginning we were having the same values, good Vcc and bad Vgg and Vss.
We decided than to change the zener, although the one used was coming from a donor
and the multimeter was giving it as working.
We tried another one (also from a donor) but the transistors were getting hot ...
We tried a replacement with a measure of 0,7 volt (which still I don't understand why it means a
voltage cut of 7 V) and everything worked fine.
Vbatt is 3,94 Volts
Vgg is - 15,47 Volts
Vss is 7,21 Volts
Vcc is 9,67 Volts
Values are slightly higher than expected, but I think we can consider it a success
We'll try to post the waveforms soon.
As for the Toroids we followed your suggestion, but L1, L2 and L3 all have a resistance of 1,3 Ohm,
and even if we measure L1+L2, or L1+L2+L3 this value doesn't change
We are however planning to buy a LCR meter or a multimeter with LCR functions,
at that point we should be able to measure the inductance.
One last note about the other thread : http://www.hpmuseum.org/forum/thread-12690.html
The pictured board has a connection problem with both the Ground trace and a couple of
interconnected PSU components.
However, now that with this experiment we can select a complete list of PSU components
proven to be working, we may go back to that project and use external wires to replace
the broken traces.
Thanks again to everyone for all the ideas !

   

BTW, what should we change to get on this PSU the exact values for Vcc, Vgg and Vss and
not these which area little higher ?

Edoardo & Alberto
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Messages In This Thread
HP-35 Power Supply Waveforms - cruff - 04-29-2018, 09:10 PM
RE: HP-35 Power Supply Waveforms - teenix - 03-28-2019, 11:06 PM
RE: HP-35 Power Supply Waveforms - cruff - 03-29-2019, 12:16 AM
RE: HP-35 Power Supply Waveforms - cruff - 04-02-2019, 12:20 AM
RE: HP-35 Power Supply Waveforms - cruff - 04-03-2019, 12:12 AM
RE: HP-35 Power Supply Waveforms - cruff - 04-03-2019, 12:59 AM
RE: HP-35 Power Supply Waveforms - albertofenini - 04-03-2019 10:26 PM
RE: HP-35 Power Supply Waveforms - cruff - 04-04-2019, 12:48 AM
RE: HP-35 Power Supply Waveforms - cruff - 04-05-2019, 11:50 PM
RE: HP-35 Power Supply Waveforms - teenix - 04-06-2019, 09:52 AM
RE: HP-35 Power Supply Waveforms - cruff - 04-06-2019, 12:36 PM
RE: HP-35 Power Supply Waveforms - cruff - 04-06-2019, 06:24 PM
RE: HP-35 Power Supply Waveforms - Zaphod - 04-09-2019, 10:34 PM
RE: HP-35 Power Supply Waveforms - cruff - 04-07-2019, 08:33 PM
RE: HP-35 Power Supply Waveforms - teenix - 04-08-2019, 09:21 PM
RE: HP-35 Power Supply Waveforms - cruff - 04-08-2019, 01:08 PM
RE: HP-35 Power Supply Waveforms - AndiGer - 04-08-2019, 02:21 PM
RE: HP-35 Power Supply Waveforms - AndiGer - 04-08-2019, 03:28 PM
RE: HP-35 Power Supply Waveforms - cruff - 04-09-2019, 12:49 AM
RE: HP-35 Power Supply Waveforms - cruff - 04-09-2019, 11:41 PM
RE: HP-35 Power Supply Waveforms - AndiGer - 04-09-2019, 05:17 PM
RE: HP-35 Power Supply Waveforms - cruff - 04-10-2019, 02:41 AM



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