DavidN71

I assume you mean the HV transistors fried from a shorted probe cable. In that case the 2N404 is an exact replacement if you can still get them. Otherwise the Ukraine/Russian MP16b works. I bought a couple of hundred of the Russian germanium transistors years ago and they have a metal shell so they are less likely to blow from overdriving. But the metal shell is base so you have to be careful about it touching another component on the board. The main thing is the transistors must be PNP and germanium (not silicon) or the bias will not be correct and they may not oscillate correctly to build up voltage. The 4.7k ohm resistor is used when doing a BNC mod, although you should never hot swap probes anyway. If you just want protection for the HV circuit without doing the BNC mod, then insert a…

I assume you mean the HV transistors fried from a shorted probe cable. In that case the 2N404 is an exact replacement if you can still get them. Otherwise the Ukraine/Russian MP16b works. I bought a couple of hundred of the Russian germanium transistors years ago and they have a metal shell so they are less likely to blow from overdriving. But the metal shell is base so you have to be careful about it touching another component on the board. The main thing is the transistors must be PNP and germanium (not silicon) or the bias will not be correct and they may not oscillate correctly to build up voltage. The 4.7k ohm resistor is used when doing a BNC mod, although you should never hot swap probes anyway. If you just want protection for the HV circuit without doing the BNC mod, then insert a 4.7K ohm 1/8 watt carbon resistor inline with the hot lead. Follow the center lead from the probe cable back to the board and put your resistor inline somewhere there.I have never used transistor sockets. If you blow them that often, you should fix the first cause.

Your email at the iCloud is overquota so I am posting this here."Finding another tube that will fit in the probe is the first challenge. The second is the CDV-700 operates on 900 volts. You will find it very difficult to fit a tube and enough zeners and resistors inside the pickle probe. The CDV comes with 3 megohm resistor inside the shell for the 6993. It is possible to add zeners and resistors inside the case of the CDV, but you have to be very careful.https://www.ebay.com/itm/162302270934 This Russian tube will just fit and is cheap. You would need 5 100v zeners turned backwards to drop the voltage into the SI-21BG's working voltage range. You may also need a 10 megohm resistor inline to make the tube stable.https://www.ebay.com/itm/NEW-RARE-GM-Tube-OCD103-019-Tested-Extend-CDV-…

Your email at the iCloud is overquota so I am posting this here."Finding another tube that will fit in the probe is the first challenge. The second is the CDV-700 operates on 900 volts. You will find it very difficult to fit a tube and enough zeners and resistors inside the pickle probe. The CDV comes with 3 megohm resistor inside the shell for the 6993. It is possible to add zeners and resistors inside the case of the CDV, but you have to be very careful.https://www.ebay.com/itm/162302270934 This Russian tube will just fit and is cheap. You would need 5 100v zeners turned backwards to drop the voltage into the SI-21BG's working voltage range. You may also need a 10 megohm resistor inline to make the tube stable.https://www.ebay.com/itm/NEW-RARE-GM-Tube-OCD103-019-Tested-Extend-CDV-700-range-to-100-mr-hr/254774108471 this is the FEMA tube that extends the range of a CDV-700 by a factor of ten and is direct plug and play. If you got it from FEMA back in the day it came with a peel and stick label to put on your CDV. That is a fair price the seller is asking. I own one. No mods needed to the CDV and you can switch back to the 6993 quickly if you want to.Range extension is difficult to predict with homemade probes. You would need to pay someone to calibrate the probe after you make it. Most people cannot legally possess sources that put out 1/2 rem or 5 rem / hour. You might as well get an ion chamber CDV like the 717 or 720 for those ranges as the CDV-717's are cheap and there is a service in Texas that will calibrate them for a reasonable fee.https://www.ebay.com/itm/VTG-VICTOREEN-CDV-715-1A-Radiological-Survey-Meter-READ-C-ALL-PICS-TESTED-C-PICS/284121946279 This one "zeros" "passed the circuit check" That's all you need to know. Nothing else is user serviceable and this one could be sent away to be calibrated."

If the CDV works correctly then you have at least 880v even if it measures otherwise.I would suspect you are loading the circuit trying to measure it. The resistor must be clean and not resting on any surface and the jumpers need to be on something clean dry and non-conductive. 1kv will bleed off easily and overload the weak HV supply on a CDV

Sorry for the delay in replying. CR means diode. CR-4 and CR-3 are headphone diodes. The headhones are mono clickers, not audio headphones. Pulses on that circuit make them click one per radiation event. The filtering capacitor on that circuit is 50v, so any common 50v (or higher) diode should do. The pulse is supposed to be about 12v, which will easily pass forward on even a cheap diode, the 50v rating is enough to block the backside of the pulse from causing a click.https://www.jonshobbies.com/civil-defense-lionel-c... has a shematic of the CDV-700 Lionel 6BCR-2 is coupled to a 50v capacitor on the low voltage side of the circuit that oscillates to provide a/c to the step up coil that drives the geiger tube. Since cr-2 is coupled to a 50v capacitor, a 50v common diode like CR-4 should …

Sorry for the delay in replying. CR means diode. CR-4 and CR-3 are headphone diodes. The headhones are mono clickers, not audio headphones. Pulses on that circuit make them click one per radiation event. The filtering capacitor on that circuit is 50v, so any common 50v (or higher) diode should do. The pulse is supposed to be about 12v, which will easily pass forward on even a cheap diode, the 50v rating is enough to block the backside of the pulse from causing a click.https://www.jonshobbies.com/civil-defense-lionel-c... has a shematic of the CDV-700 Lionel 6BCR-2 is coupled to a 50v capacitor on the low voltage side of the circuit that oscillates to provide a/c to the step up coil that drives the geiger tube. Since cr-2 is coupled to a 50v capacitor, a 50v common diode like CR-4 should be used.

Yes, that seems to be one that is still made. 50c each in small quantities.https://www.allelectronics.com/item/r6000/0.2-amp-6000-v-rectifier/1.html

I avoid working on Anton's unless they are broke. They are much more complicated than ENi's and Lionel's. When replacing a capacitor that is known bad the voltage matters, as does the capacitance and whether the cap is polarized. Like you said, I don't know of a mylar cap with that rating. Maybe someone tried a fix and it didn't work. https://www.ebay.com/sch/i.html?_nkw=high%20voltage%20ceramic%20caps eBay is a pretty good place to start. The blue caps are not mylar, they are ceramic. Buy at least 2kv, 3kv is better. The current rating system is the actual voltage the cap will fail, the old system when things were made in the US was more lenient.

You don't make a corotron replacement. You measure the unregulated voltage and then add zener backwards and check again. If the CDV works and the voltage is below 930v then you are probably safe. I have one ENi that works fine at 880v. Using zeners backwards to drop voltage is an art. They were not rated to do that, but will if the current is kept low enough. CDV's can't push much current so that works well.

It's a 1N34 and it's obsolete. It's was a germanium diode. That matters. The forward voltage is lower on germanium than silicon. The 1N34a is the modern replacement or use a 1N270. Just make sure you are getting a germanium diode. eBay has both in germanium. They are commonly used in fuzz boxes for guitar effects.

300v zeners have become almost impossible to find. Lately I have been forced to use 200 and 100v zeners.https://www.ebay.com/itm/1N5388B-200V-5W-ZENER-DIO...200v OnSemi brand 1N5388B 200v zeners for cheap.

It worked with my Canon camera. One lipo and one dummy cell = 3.2v. An older camera like the 120sx was made to operate on alkaline cells. I got rid on my 120sx because it was so unstable with 2 cells. I now own a Kodak AZ401 that uses 4 alkaline cells and it runs great. Modern cameras are just too power hungry to get by with 2 AA cells.The run time isn't as long with lipos though. Nicads have an even lower voltage than alkaline cells. I avoid them. Nicads are toxic, too. Nickel metal hydride cells usually work if Nicads will and don't have the toxic cadmium in them.If the camera is voltage sensitive, and most are, the 2 nicads fully charged is 2.9v. Under load the 2 nicads will drop to 2.4v but the camera will complain that the batteries are low when the batteries drop below 2.8v. The lit…

It worked with my Canon camera. One lipo and one dummy cell = 3.2v. An older camera like the 120sx was made to operate on alkaline cells. I got rid on my 120sx because it was so unstable with 2 cells. I now own a Kodak AZ401 that uses 4 alkaline cells and it runs great. Modern cameras are just too power hungry to get by with 2 AA cells.The run time isn't as long with lipos though. Nicads have an even lower voltage than alkaline cells. I avoid them. Nicads are toxic, too. Nickel metal hydride cells usually work if Nicads will and don't have the toxic cadmium in them.If the camera is voltage sensitive, and most are, the 2 nicads fully charged is 2.9v. Under load the 2 nicads will drop to 2.4v but the camera will complain that the batteries are low when the batteries drop below 2.8v. The lithium iron phosphate cell is 3.2v fully charged. The absolute bottom discharge voltage is 2.5v, but the current output will be so low long before then that the camera will shut off.

I wouldn't put 28v through an 18v motor unless I had a couple of spares just in case it burned up the motor.

No reason, except that lithium cells are cheap and with 6 cells you get longer run time and don't need to change the charger except to add a couple of diodes. If the cost of the cell matters that much, then you could certainly do that. The tool won't care much.

It's in one of the pictures. I cropped it below. The rectifiers are under the black shrink wrap.

I was in a super Walmart today and saw for $50US a Black and Decker cordless drill, 2 20v lithium batteries and a charger. The batteries look almost identical from the outside to these Scotts.12020a's. But, since this is B&D, the cells are probably rejects from somewhere. They should still work in a drill, though. Drills don't pull obscene amps like weed whackers and leaf blowers and circular saws.

Thanks, our church has one for plays. The fog solution is organic and the safe version of glycol antifreeze, so it does caramalize eventually. The fog and cleaning solutions are sold separate from the machine and someone didn't read the instructions and clean out the machine before storing it away. Once I followed your instructions the pump works again. If you can't hear the pump, it's stuck. Otherwise it makes a clearly audible clicking sound. Thanks again.

You don't need to. Just take a thin strand of bright copper wire and wrap it between pins 2 and 3 if you are not sure. You do not need to solder it, just wrap it and put the tube in the socket as you would normally.

The white PVC connectors in between the tee and the 2 gate valves are there to make disassembly easier. The pump head was reused when the original pump burned out years ago and was replaced by the one pictured now.

The pump is a standard 1 1/2 HP [120v/240v] irrigation pump from Home Depot.The pump head output is 1 1/2", which is the same as the fire hose.I unscrewed the 1 1/2" output pipe and replaced it with a 1 1/2" tee. The NPT to NST adapter screws into the tee and the hose into that.The nozzle screws on the fire hose just like a garden hose nozzle does.No tools needed except a pipe wrench. The picture of the pump shows the connection there.

Thanks. I avoid cordless tools except where I don't have an easy choice. It seems batteries are expensive and don't last very long. My parents used to live on a boat, so there were many times safety came first even though they had more onboard 120v power away from the dock than most houses. I put a vacuum cleaner cord on a Makita drill once and ran it from my car battery. The on-board battery could not be swapped out. When it ran dead I had to wait for a recharge.

The cheap cells I bought don't do well on a weed wacker, but they aren't soldered in, so they can be swapped out for better if I wanted. I still have a couple of cheap nicad packs and between all 5 I can do what needs to be done. The cheap cells were like $1 each so I didn't expect miracles. I have bought completed packs from HobbyKing and they are careful to grade their packs/cells and charge accordingly. I built 2 packs from 3.2v lithium iron phosphate cells for a cordless drill at work and those work well. Very fast recharge times.But even those had issues with the spring loaded battery holders softening from heat when improperly recharged. The lithium iron phosphate cells got hot enough to melt off the plastic label when overcharged. I was using the wrong charger. They also quit worki…

The cheap cells I bought don't do well on a weed wacker, but they aren't soldered in, so they can be swapped out for better if I wanted. I still have a couple of cheap nicad packs and between all 5 I can do what needs to be done. The cheap cells were like $1 each so I didn't expect miracles. I have bought completed packs from HobbyKing and they are careful to grade their packs/cells and charge accordingly. I built 2 packs from 3.2v lithium iron phosphate cells for a cordless drill at work and those work well. Very fast recharge times.But even those had issues with the spring loaded battery holders softening from heat when improperly recharged. The lithium iron phosphate cells got hot enough to melt off the plastic label when overcharged. I was using the wrong charger. They also quit working, but at least didn't catch fire.

For high current draw you need cells rated with 25C. A weed wacker is pretty much a dead short when trimming grass. That's one of the reasons the original nicads don't last long. A cordless drill doesn't pull anywhere near the current and therefore is much gentler on the battery pack.http://www.tested.com/tech/502351-rc-battery-guide-basics-lithium-polymer-batteries/