I have an MRC Tech 4 Dual power pack for 2-cab operation. If I wanted to connect two inexpensive 2 lead rectangular panel voltmeters (one for each cab control)- inexpensive 20 volt DC ones that I see online- and place them on my control panel, how would I wire them?
The idea is to show track voltage for each cab control.
Cedarwoodron
The voltage meters goes across the + and - poles of your output.
BUT… unless you have meters with the “0” in the center then you will harm the meter when you put the power supply in reverse.
You can put rectifyers back to back on one leg of the meter so that you will only pass forward voltage to the meter.
An Ammeter stays on the + side of circuit between the power supply and the railroad. Same deal with the recitfyers.
ROAR
I use LCD panel meters on my control panel. They will read negative or positive voltage but all three wire meters need an isolated power source to power the meter (wall wart). I use cheapo 9 volt DC wall warts to power my three wire meters.
Two three wire meters will require two wall warts to prevent shorting between cabs on your Tech 4. If you can find four wire meters a single wall wart or any 12 volt DC constant power source will power both meters.
This is my control panel.
Those cheap online ones, they just connect where the track leads go. They will show - for one direction, but the voltage will be right. The ones with only 2 wires won’t even turn on until you get above a certain voltage though. You really want the kind that have 4 wires, 2 to connect to the circuit to test, and 2 to power the meter itself. The meter power would need to come from a seperate power supply liek a small wall wart rated for whatever the specifications on the meter show it needs.
–Randy
If You want a real simple way to have what You want…that is if You are good with working with small wood cabinets…which I scratch built out of 1/4’’ thick birch lattice. Installed a DC analog volt meter into the wood cabinet which is held in place by velcro strips on top of a MRC TechII 1500. The DPDT center-off toggle to the left of the meter is connected right to the variable DC output on the pack. Two wires go to one end of the toggle and to the far end of the toggle, but they are reversed on the two leads…the two center leads go to the meter. The toggle is oriented so it matches the reversing switch on the pack. When You want to reverse polarity with the reverseing switch, You put the toggle in the center position, switch the polarity with reversing switch and move the toggle to the position that the reversing switch is in. Seems like a lot of work, but it’s really quite simple…I use it for work bench purposes, since the early 80’s. You’ll see it in the top right hand corner of the photo:
I could have wired it directly to the reversing switch inside the pack…but did not want to. That pack has some security screws, that would not come out without major surgery…LOL
Photo may be clicked on for a larger view:
Take Care! [:D]
Frank
Wanna borrow a screwdriver? I now have 2 sets that have pretty much every kind of oddball bit for any sort of electronic gizmo. I don’t have my old tech II any more to see if these kits have the type of screws used on those, but there really are a wide variety of really strange looking bits in these sets.
–Randy
I had one many years ago. I believe it looked like a Torx but a pin stuck up in the middle of the screw required the tool to have a hole in the center. The bit fit in my Xcelite screwdriver handle.
Rich
Yep, have a couple of those. Believe it not, I needed one to unscrew a recoil starter assembly from the engine shroud. (Briggs & Statton 8hp. motor). They don’t want the average guy to work on ANY thing any more! I was SUPPOSED to take the engine shroud, with recoil assembly attached, to my “Local B&S service center” and have it all replaced. [8o|]
Sorry! way [#offtopic]
Mike.
These have the head like the shape of a cone with a slot in the center. You could stick a flat blade screw driver in the slot…but only tighten it clockwise…counter-clockwise the blade would slip out of the slot. They are counter-sunk in a 1/4’’ hole. You could drill the head off or have the right tool…LOL
But heck…it’s been working since the 80’s so if it ain’t broke, I’m not going to fix it.
Speaking of security Torx screws…I bought an 85’ Secretary Of State Police Interceptor Crown Victoria at auction once. The carb was a variable ventura four barrel…needed a rebuild bad…to My dismay…that carb was loaded with those security Torx screws…wound up buying a whole set of those, just to rebuild that carburetor. Set was not cheap either. Would have just replaced the carb, but would have also had to replace the intake manifold…that was also weird…two small barrels, two big barrels. The rebuild worked great though.
Now back to Our regularly scheduled dead thread…LOL.
Take Care! [:D]
Frank