[:'(]Can anyyone tell me the resistive value for the resistor R12 on the receiver board in my tank? I have an S&S Panther with a bad cannon. Was working sort of, now it does not work. I get 2 volts at the motor, and I traced bsack to a charred black and silver resistor on the receiver board in the tank. All other motors get around 6 volts, so I would assume this is the issue. Also, the shooting LED no longer lights up, but that's understandable since the dropped voltage for it is from the 2 volts instead of 6 volts.

Anyway, if anyone can tell me the value for that resistor it would be great. I am familiar with repairing electronics, but this resistor is charcoal....must have been bad from the factory.


Thanks all. [8D]

Dmon1996

you have a picture? My eyes are getting bad I cannot find R-12 with a magnafying glass, i could ohm it out for you if you can point it out!

The Blitz

R12 is 1K according to samarkh's schematic

Thanks, I'll try a 1K ohm resistor.

Dmon1996

Thanks for the assistance. As it turned out, I misread and I needed R11, not R12. But I found the schematics and found that I needed a 2.2 ohm resistor. I scrounged thru my old electronics junk and found one. Cut out the charcoal that was a resistor and soldered this one in. That fixed the voltage to the motor. However I found that the motor had excessive resistance (real resistance, not electrical). Seems that a slim piece of casting from the motor end cap had been inside the plastic "bushing" and as such it was difficult to turn the motor. I carefully bent out the tabs, disassembled the motor and cleaned it out. After reassembly it was turning far easier. I reassembled the tank (resoldering several wires- those wires are very brittle! They broke far too easily....) and am now out of the motor pool and ready for battle!

This forum rocks. I've only been in it for less than a week and already I've gotten help and advice on several issues. I just wish you guys were from my neck of the woods so I could buy a round....


Dmon1996

Hi all,

Just a note, in my many years of experience in design and repairing electronics (and electrical). It is seldom (but not impossible) that a "passive" component just fails. By passive I mean a resistor, capacitor or inductor. Usually the culprit is something else like an active component; transistor, diode, short etc. So if a resistor fails, you replace it, don't be surprised if it blows again. Don't try a higher power replacement either.

In this case the solution by Dmon1996 supports my post, as in most cases I beleive it will be the same. This forum will be a great help, but I just would like to point out that the blackened part is not always the problem.

Yep, like people that replace fuses in some electrical items - "there, its working again" (not "let's find why it blew a fuse in the first place")

Sorry for stepping in and do some interruption, but I have to say something different. please check the WiKi link below and find out how bad capacitor is common problem for many devices.

[link=http://en.wikipedia.org/wiki/Capacitor_plague]Capacitor_plague[/link]

Yeah that started many years ago with some poorly made Taiwanese capacitors - many PC motherboards and other devices used them ( "its a capacitor, what could go wrong" ), not many manufacturers came forward and admitted component faults. They were just dirt-cheap (hence everyone switched supply to those) just weren't up the task, overheated, bulged and died quickly....

Good point, but in a bad component specification we would see many similar failures. Just like automotive or appliance recalls. Like "hey bad ???, send in to replace".

But uncommon failures are usually from unique usage, random component failure, bad/inconsistent manufacturing, etc. I've repaired far too many items with simple failures that should have been returned or maybe reported. But with overseas units, with no warrantee, what do you do?

I'm fortunate enough to be able to fix some/most of these issues, but then again I rarely use something as is and immediately modify it. This results in not seeing or dealing with manufacturing issues, or if encountered not caring.

My two WSN T34/85 (first ones no Ir combat) both had issues, and both issues were irrelevent with the mods I planned for them. Someone buying it for what it was suppposed to be would have had a defective product

BTW: I bought both of the T34/85 as is, so defective issues were a mute point anyway. Be careful when you buy!

As a computer technician, I will agree with the whole bad cap issue. I have had to replace bad motherboards where the entire bank of capacitors along the CPU have bulged and leaked. The most notorious seemed to be several models of HP as well as a few models of generic PC motherboards made by Asus.

Now, that being said..... HP is a fine manufacturer of computers and laptops, and Asus is a premium motherboard manufacturer. I don't want anyone to think they are crappy- just a bad run (probably the same crappy Tiawan caps in both).

Dmon

It's a good bet that the 'culprit' in your issue was the mechanical problem in the motor. Stalled DC motor draws much more current, hence burned component some where along the line...... 'nuff said.

Keeping in line with Blitz's comment about fuzes...I replaced a 13-board in my Panzer III a while back because something burned and the right track wouldn't quit running. I couldn't figure it out then. However, 123splat mentioned a stalled motor. I've noticed recently that when I run my PzIII about 1/2 to 2/3 of the time I can hear a humming when it stops moving. It's almost like a motor is trying to run but shouldn't be. (helps to run it occasionally without the smoker and the volume turned off ). Is that a stalled motor? If so, how do I fix it?

Well "COULD" be a stall. When the tank stops, is the right stick at null or just close to null?

Stall is just that. At a certain power level, the motor stops running because (usually) of some mechanical load overpowering the motor's output. Motor turns into a big inductor and passes more and more current. Stall problem only exists electrically when the motor has power (Usually that is NOT the case when the tank is supposed to be stopped, right stick at null).

Pull the motor in question and check on how freely the shaft will turn with the motor out of the gear box. If it is binding, you will have to disassemble the motor to discover the cause (could be a number of things).

If motor turns freely out of gear box, obviously, the next thing to check is the gears and the motor's pinion to gearbox mesh with the motor re-installed. If you now have binding load on the primary gears in the gearbox (the ones where the motor connected, not the gearbox output shaft), you could probablly fix that by gear break-in process, followed by judicious cleaning and re-lube of the gearbox.

If none of the above.... you might have an imbalance in the motor drive (commonly compensated by setting the trims on the xmitr). Cause could be output of the driver board electtonics or the xmitr signal biases. If so, with low or null inputs from the xmitr, the driver board is still getting input from the opposing drive (trim bias the forward/reverse drive to x clicks reverse, in zero bias, the motors still want to run forward, so you trim to reverse until the motors stop at null stick, if the trim gets bumped, at null stick the motors still get power, but not enough to move the tank). In your issue, if this is the case, it would be with the left/right trim for the right stick if it is just one motor humming. This is more likely than a motor stall.

BUT,,, is the humming comming from the motor(s), or the speaker? that would be another issue.

I'm pretty sure that it's not the speaker. I turn the volume all the way down and it's dead quiet all the way through the start-up, running and shut-down processes. Also, the humming doesn't happen all of the time. So, I think it's probably the motor or the trim like you suggested. I'll try those. I don't think it's the gears; they're nylon. I didn't think that they needed a break-in.

Thanks.