Paying full attention - what model DMM do you have if you can't directly connect it? I have an 87V I'm happy to connect as it's rated for 1KV.
On Friday, May 21, 2021 at 11:38:27 PM UTC+1 gregebert wrote: > UPDATE 1: I built the power supply/driver board and completed some basic > testing. I installed all components EXCEPT the transistors for the diff-amp > that drives the CRT. The standby current at 12V is zero. The HV supply can > be enabled by grounding the POWER_ON signal; that causes the inverter to > run and the current is 170mA. The neon bulb is on and it's supply is 306V; > the +5 and -5 supplies also work. The filament supply voltage on my scope > is about 500kHz, somewhat sinusoidal, and about 17V pk-pk, which is about > 6.3 Vrms for a pure sinusoid. The HV is beyond the range of my DMM so I had > to put a 10meg resistor in-series to double the range (inaccurately, > because it's a 10% resistor) and measure around 1270 VDC. > > Next step is to build the other board. Stay tuned. > > On Thursday, May 20, 2021 at 7:34:52 AM UTC-7 John Snow wrote: > >> >> I've been checking over solderjoints, hoping to find a Q or U with a >> solderbridge, no luck. >> >> Ah, I hadn't made the connection - I found your build guide before, it's >> what made me decide to order one. It's been useful for making A or B >> comparions for anything standing out. >> >> I've also been checking over the circuitboard hoping to find a Q or U >> inverted, but they're all following the soldermask guides. >> >> There's no breakout for and ground VCC_300 to easily probe? >> On Thursday, May 20, 2021 at 8:10:06 AM UTC+1 Paolo Cravero wrote: >> >>> John, >>> pictures of my build are here: >>> https://ik1zyw.blogspot.com/2020/10/kit-oscilloscope-clock-8sj31j-review-3.html >>> >>> The code on the HV board is the same. I think I reversed a 79Lxx, but >>> the smell of it burning was too obvious and I cannot tell what the effect >>> was on the CRT. >>> >>> I do get intermittent failure probably caused by a cold joint at a >>> ground point that was not designed with thermal relief and it took me a >>> while to solder. >>> >>> Paolo >>> >>> >>> On Thu, May 20, 2021 at 12:49 AM John Snow <[email protected]> wrote: >>> >>>> Hi Paolo, >>>> >>>> no filament glow after one minute powered on, >>>> >>>> both fuses continuity checked, they've not blown >>>> >>>> I'm getting 60V across the indicator bulb. >>>> >>>> Which voltage regulator did you reverse? >>>> >>>> -- >>>> >>> You received this message because you are subscribed to the Google >>>> Groups "neonixie-l" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to [email protected]. >>>> >>> To view this discussion on the web, visit >>>> https://groups.google.com/d/msgid/neonixie-l/3f6e2a4a-ed6d-485d-9ccc-a0dfc157b451n%40googlegroups.com >>>> >>>> <https://groups.google.com/d/msgid/neonixie-l/3f6e2a4a-ed6d-485d-9ccc-a0dfc157b451n%40googlegroups.com?utm_medium=email&utm_source=footer> >>>> . >>>> >>> -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/99e05f50-a690-4325-a59a-87f8621cc6d7n%40googlegroups.com.
