| Electronics > Repair |
| HP 6177B series zener diodes ?? |
| (1/2) > >> |
| coppercone2:
I am replacing the diode on this thing because alot of them are like chipped. I got all the replacements but on the PCB there is a deviation from the manual. VR13 has two diodes soldered together in series. The manual says 6.19V 5% 1N753. But on the PCB there is two diodes. one is a "light blue (almost greyish), yellow ----> brown" (brown I believe indicates the diode orientation, on black glass body). The second diode looks like a much physically smaller diode. its bands are "brown, deep sky blue, yellow". So it looks like this "light blue, yellow, brown" -> yellow, sky blue, brown WTF is this?? they twisted the leads together and bend it over with alot of uncut lead left over But when you probe it, it measures like a clamp. That is, both diodes are facing each other. so positive lead in middle makes both ends beep. The smaller diode drop is 0.5, the bigger one is 0.7 |
| coppercone2:
--- End quote --- did they decide to drop the voltage by 0.5 volts? as far as I can tell thats all it does |
| coppercone2:
Oh Its in change notes but not documented in the diagram. its hp 1901-0461 |
| andrewtaylor:
--- Quote from: coppercone2 on May 16, 2024, 05:23:11 am --- did they decide to drop the voltage by 0.5 volts? as far as I can tell thats all it does --- End quote --- the simple but significant reason: temperature compensation for the voltage in the overall circuit.. |
| coppercone2:
is this still recommended with modern diodes? the device did not improve by enough to negate this benefit did it? |
| Navigation |
| Message Index |
| Next page |