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/f615d2a1-f42f-4116-b352-92b5828845d8n%40googlegroups.com.
