So after some delay I am finally getting back to this build.
I am wanting to put neon flashers in, which as the instructions say can be done.
What high voltage pin do I use? It just says use a hv pin, but doesn’t specify which one.
What type of resistor should I use? It says 56k-100k. I have both, they are rated 5w, will this be enough?
You can get the HV from either pin 4 of POWER (SV1) connector or from the HV test point next to the LEDS (SV6) connector.
Where did you get those resistor values from? The copy of the manual I'm looking at says to use 270K resistors. The actual correct resistor value is highly dependent on what neons you choose. For example, on one of my clocks I used NE-2 neon bulbs and settled on 150K resistors after some experimentation.
Be sure to use one resistor for each neon bulb. Pairing up neons on one resistor will not work. Whichever one has the lower striking voltage (tolerances!) will light up and steal all the current, keeping the other one(s) from lighting.
5 Watt resistors are absurdly large and probably won't fit on the board. 1/4 watt or 1/2 watt is plenty.
Look into it later when the dust is clearing off the crater.
I’m trying to add some images to show some things, not having much luck. Please see the attached images of the manual which states the resistor values - once I can get them up.
There is no marking on the neons at all. I am told they are INS-1, that’s what they were sold as. See attached photo - again once I can get them up.
I miss typed the resistor value should have been 0.5
I’m not very knowledgeable with regards to resistors.
What difference will putting a 100k on make compared to a 56k?
Okay, understood about 0.5W versus 5.0W. 0.5W or 0.25W are fine.
I was under the impression we were talking about a Classic Rev.6 board here, but the only Classic manual I can find "56-100K resistor" is the Rev.4. Those values are too low for INS-1s. The Rev.6 manual is closer to reality with its "270K resistor". I ran a search of the forum to refresh my memory of past INS-1 discussions and found that the resistors have been debated before. At least one person had good results with 200K, Another speaks of 220K, Consensus seems to be that 56-100K is too low. Plenty of complaining about INS-1s being temperamental and unstable too. Good luck.
Note that the INS-1 has polarity. There's a dot on the pinched part of the glass. It indicates the anode.
With neon bulbs the resistor serves as a current limiter. Too high a resistor value and the neon will either refuse to light up or light weakly and flicker. Too low a resistor value and the neon runs hot or fails prematurely or just plain blows up.
Back of envelope resistor calc for an INS-1:
Maintaining voltage = 55v
Desired current = 0.5mA
Supply voltage = 170v
Awesome thanks for that your amazing.
I have got 220k resistors too which is great.
So the neons should be connected between Pin 4 of SV1 and Pin 4 of SV6. Just want to make sure, I case I cause issues on the board.