I have an Aneng UT61e; cheap but quite good. One of my scopes has a pair of 100x probes that lets me look at a few kV, but I was too lazy to bring it up today. If I run into problems I'll post some screenshots.
After installing the diff-amp transistors and Q1, current-drain increased to 360mA. I suggest you bench-test your power-supply board by itself first; disconnect all cables, and jumper J5-4 and J5-5 together to enable the HV supply. Make sure all generated voltages are correct, especially the 300V supply (should be around 305V per the instructions). On Friday, May 21, 2021 at 4:10:55 PM UTC-7 John Snow wrote: > 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/96129fff-2dc9-48c4-9047-ae9f30112735n%40googlegroups.com.
