Trash picked treasure

[Diesellpower]

So my aunt was throwing out a ton of boxes of old stuff. I was helping her move it out for trash day. It seems that my uncle was into RC stuff 30ish years ago. I took home about 6 boxes of stuff for planes, boats and cars. Found a complete gold pan in there. Lots of foam tires, extra wheels, servos, batteries, chargers, misc stuff and an extra motor. So the batteries wouldnt take a charge (suprize). Without anything to lose, I gave them a couple momentary buzzes with my welder and they started drawing current from the chargers. I actually got it to run! For about 100 feet before that antique battery pack fell asleep.
I have been researching like mad for the last few days, as I didn't know squat about RC anything outside of a toys-r-us car for Christmas when I was a kid. I am hoping you guys can steer me in the right direction to get this thing running again. Maybe I can build a dirt track for it in the woods out back. All paperwork and receipts I could find were were the early to mid 1980s. And in 80s dollars, this stuff was expensive as hell.

Right now, I assume that at minimum, I'll need new batteries for the motor and radio. When I put in the old ones, it was really "twitchy". The motor would randomly go forwards for a moment. The steering servo worked most of the time, but would sometimes go full right for a moment. This seemed independent of when the motor would twitch.

At any rate, now that I know that everything is somewhat functional, I want to get into usable condition. There seems to be about a hundred routes to take to get there. I have a few hundred bucks of discretionary money that the wife doesn't know about, but would like to keep the budget low until I see if its a hobby that is going to grab me. (most of them do)

Pictures, or it didn't happen:

[BattleTrak]

Nice trash buggy! How does the bottom of the chassis look? To take the path of least resistance..I would get a moderate capacity 7.2volt nickel metal hydride (Nimh) battery with a Tamiya connector and and a simple charger to get it running again. These Dynamite ones are inexpensive and probably in stock at your local hobby shop..
https://www.dynamitesale.com/dynamite-speedpack2-7-2v-2400mah-6c-nimh-flat-tamiya-for-batteries/

https://www.dynamitesale.com/dynamite-prophet-sport-mini-50w-multichemistry-charger-for-chargers/

Keep in mind it’s an old buggy and should be lightly driven. It probably needs the gearbox and shocks rebuilt before you go too crazy with it.

[Diesellpower]

The bottom seems pretty nice. Has some scratches back under the motor. After draining the battery and recharging again, it runs for a good 3-4 minutes and is faster then my dog. The smaller battery for the radio doesnt have any kind of mount tho. it just flops around in there.

Has anyone seen a battery charger like this before? I have never heard of charging a battery by a set current on a timer. There's only one hobby shop left here, and it's all the way on the other side of town. So it's online shopping for me.

[Frankentruck]

Yeah I used to have a similar charger. Lower amps charges slower but was easier on the battery (not getting too hot). Higher amps when impatient and need it changed sooner. 3 to 4 min run time isn't terrible for an older battery. Is that in grass, on dirt, or pavement? A new higher mAh battery will last much longer but will also get the motor hotter with the longer run time.

With a slightly newer receiver that supports a battery eliminator circuit (BEC) you wouldn't need the 4AA pack at all.

Really that's a pretty nice condition buggy. It doesn't have much scraping from any past concrete running.

[juicedcoupe]

With a slightly newer receiver that supports a battery eliminator circuit (BEC) you wouldn't need the 4AA pack at all.

That isn't what a BEC receiver means. A BEC receiver allows higher voltage (usually 7.2-8.4) voltage to be supplied directly to the battery port. They typically have a resistor between the battery post and the output rails.

The positive and negetive rails of the receiver should be common, allowing the esc's BEC to power it. That receiver should be fine, assuming that the esc is wired properly (G plug!).

[Frankentruck]

I was pretty sure you needed a BEC receiver for the main battery power from the ESC to be able to be used to run the steering servo. I could be mistaken though.

From the Futaba 2PKA radio manual:
.

[Diesellpower]

The manual for the speed controllwr says that it has a BEC that suplies 5v @ 0.5A I am making an asumption that it isnt enough since it isnt hooked up. There is an extra small gauge black and red wire comming out of it that isnt hooked up to anything.
It has a smaller futaba 4.8v battery pack that plugs into the radio through a second on/off switch. Thats the one that has nowhere to mount securely.

After i get to cleaning it up and get a better handle on what electronics are available, i might replace it all with somthing from this century.

[Frankentruck]

If you remove the 4.8v battery pack, with a fully charged battery can you also steer the buggy? If not, then it just needs a BEC compatible receiver.

[juicedcoupe]

I was pretty sure you needed a BEC receiver for the main battery power from the ESC to be able to be used to run the steering servo. I could be mistaken though.

From the Futaba 2PKA radio manual:
.
Screenshot_20221023-154253.png

Back in the day, it was common to use a small resistor and diode as a external "BEC". Even some newer (Tamiya) esc's have a separate power wire that must be used with a BEC receiver.

Cars with MSC's need an external battery pack or power from the main pack. If using the main pack, you use a BEC receiver or external BEC.

I'll try to get some pictures later.

[juicedcoupe]

The first picture is a non-bec receiver. The battery and both channels share the same positive and negative rails. This can still be used with an esc with internal bec. Truthfully, most modern receivers aren't bec. Do not directly connect more than ~6 volts directly to these.

This is an older Futaba bec receiver. You can see the separate circuitry, along which the capacitor and surface mount resistor. You can supply these with 6 or 7 cell packs.

I also have an old Airtronics bec receiver that uses a transistor to limit voltage. I'd take a picture of it but the circuitry is hard to follow.

[juicedcoupe]

The manual for the speed controllwr says that it has a BEC that suplies 5v @ 0.5A I am making an asumption that it isnt enough since it isnt hooked up. There is an extra small gauge black and red wire comming out of it that isnt hooked up to anything.
It has a smaller futaba 4.8v battery pack that plugs into the radio through a second on/off switch. Thats the one that has nowhere to mount securely.

After i get to cleaning it up and get a better handle on what electronics are available, i might replace it all with somthing from this century.

That is sufficient power for early analog servos. Unless something is wrong, there should be no need for the secondary battery pack. The esc should back power in to supply the receiver and servo.

The two smaller wires were for powering a couple small led brake lights, if you wanted.


A more modern radio system that uses common plugs would make things easier, and free up some space. A reversible esc would also make the car more enjoyable. If you shop around, you can probably find a cheaper radio system, servo, and a Hobbywing 1060 esc for $50-60.

[Diesellpower]

I ordered that dynamite charger and battery. I also ordered a bearing kit for the car.

U am looking at this on amazon. This is what i need to get rid of the second battery, right?
https://www.amazon.com/ShareGoo-Converter-Module-Quadcopter-Holder/dp/B075QJDW3Q/ref=mp_s_a_1_9?keywords=rc+ubec&qid=1666625252&qu=eyJxc2MiOiIzLjA3IiwicXNhIjoiMi40NyIsInFzcCI6IjIuMjgifQ%3D%3D&sr=8-9#aw-udpv3-customer-reviews_feature_div

Also, what do i need for the transmission? Just clean it out good and re lube?

Ill save the shocks for last. You can see some oil residue like they have leaked some, but for the moment, they are still keeping the car from bouncing if i drop it from a foot or so off the ground.

[juicedcoupe]

The Novak esc has an internal bec. It shouldn't need anything else.

[Diesellpower]

Will it just backfeed the power through the one set of wires connecting the radio to the esc? The first time i ran it, nothing worked without the smaller battery plugged in.
The battery only lasted about 20 seconds tho, so maby it just didnt have enough juice.

After running it dead and charging it again, it ran for several minutes, so ill try it again.

[juicedcoupe]

Make sure that all three wires on the esc are connected properly.

It looks like your uncle cut the original plug off and replaced it with a Futaba G plug. Those were phased out long before that esc was produced.

That esc would have originally came with the newer Futaba J plug, which is similar to what everyone uses now.



But yes, the esc should back power into the receiver from the main battery pack.

With the exception of one msc equipped car, all of my 30+ cars are wired like this.