The ONLY thing is that there's one wire hanging and I don't have a clue where it's supposed to be connected to.
...
The wire comes from the selection knob.
The oscillator that generates high voltage seems to work (I hear it buzzing) and I've measured like 300 V.
About the tv screen you mean the old tvs with tubes right? I tried the oscilloscope screen with no results.
I knew about the americium inside smoke detector, I actually was thinking on buying one haha
Unfortunately I can't read the schematic you provided, it's not quite the same model.
If it doesn't work, I'd like to test the geiger tube. In that regard BradtheRad, or anybody, if you have any more information about how to do it I'd appreciate it. I should also test the high DC voltage output.
I've added a picture where it shows the headset plug as I found it. It seems to me it's connected to the tube's ground mesh. How should I connect a speaker or headset in order to hear the "tac tac" (if it ever works!).
The regenerative amplifier in the Victoreen is a rather unusual detail. Most instruments are using a more conventional muti-stage amplifier, as I remember it from a F&H GM device.I didn't suppose the Victoreen schematic would match your unit.
Guys! Success! Well sort of!
I plugged the missing wire and the headset ring to an old PC speaker I had (powered) and.. tac tac tac!
I've measure around 30 tacs per minute (more or less, it's quite random) at around 0.4 kV with the x1000 scale. If I unplug the tube, then I don't get any tac, so quite happy to see that the tube works!
I'm also hearing the oscillator high frecuency buzz through the spearkers. Is it possible it's just peaking it up? The connections are improvised and the speaker quality is bad I think, I guess I could take out it with some filtering.
So it seems to me that the wire hanging out was just the headset wire. The problem now is that I'm not getting any visual readings (the galvanometer). The needle just doesn't move with the tacs...
No, I didn't suppose the Victoreen schematic would match your unit. There could be other schematics on the internet. I had to look at several because there was an A and B schematic for mine.
Also check into discussion groups. I followed one on Yahoo for a while. It may still be there.
Since it appears to have a built-in kV test, you may as well trust it for the time being. Even if the volt level is borderline, there will probably be particles that are strong enough to trigger the tube to fire.
Asking just in case... did your unit come with a radioactive sample attached to the housing? I found one on mine.
I tried a few things. Headphones, an audio speaker. These get awkward and bulky. I ended up soldering a piezo beeper to the contacts and it works fine.
Check for voltage coming from the tube mesh. If it's low voltage then you can go a similar route as I did.
The picture shows the wire attached to a round grounding ring. Must be meant for the headphone jack.
It appears that someone removed the headphone jack.
All of a sudden it is plausible that your loose wire is the output of the clicks. Could it go to the missing headphone jack? I think so.
However in case it is not the output...
Your picture shows a row of 5 solder joints, each with a wire attached, except one does not (labeled below):
I think I see it from both sides. It seems to have no purpose except if a wire were attached. Look closely at it for any hint of tiny broken wires. Or even a tiny spot of copper amidst the solder?
There's low resistance between every pair. I was shocked not see the needle move when I tested with it with the multimeter (usually the current from the ohmeter causes some deflextion!)
I'm intrigued about the black wires. I noticed that the lamp, which I suppose it must light as it detects a tac, doesn't light at all either. Seems to be a LED, since it has polarity and I measured like 8 kohms (!). I'm tempted to bypass this LED (shortcircuit it) and see what happens, should I do it?
Also the AC->DC system makes no sense to me. The original battery is 6V so the rectifier's output should be ~8V tops, but I measured like 37 Volts at the output of the rectifier!!! (wtf!) The transformer gives 26V for 220V which doesn't make any sense. If it were for 110V it'd give 13V which is still a lot! The rectifier bridge output is connected to +Vcc. I'm lucky if I didn't burn anything!
The counter says it's either for 110 or 220V. The weird thing is that the cable comes with a drop resistor (see the pictures). I'm going to check that out, maybe that's the problem. Edit: I checked, it seems fine, a series resistor of 1.8kohms not big deal it shouldn't drop too much voltage under normal operation...
I guess the transformer is bad, what do you think?
The counter didn't come with any radioactive source. I found out that it's nearly impossible to detect radiation from bananas since it's too weak compared to background. Also a smoke detector doesn't look like a good option because (most likely) my tube can't detect alpha particles. I'm going to ask at the faculty of natural sciences , I heard the have some radioactive rocks...
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?