Futaba fp-t3pg magnum senior partial tear down

[JosephS]

I

I purchased futaba magnum senior with some case damage, but otherwise in good condition some time ago. It was also missing the battery cover.
I won an auction on a second more complete one.

The new one was in rough shape with a lot of oxidation on the metal parts. As well the trigger was sticky.

I started to tear down the recent one to see if I can transpose plastics.

Most unexpected is that the pistol grips are removable.

There are brass plates underneath that are soldered to the negative/ground plane.

The grip portion can’t be fully split until the back of the controller is removed. It holds the split sides together. As well there is a screw in the case right over the split area that controls the tightness of the rotation. It looks like if you tighten this down you can lock the controller at a preferred angle.

Here is behind the din connector that the controller used to charge as well as for external power.

It looks like it would be simple to use a life or lipo battery externally using a custom din plug.

[RC10th]

Keep going

These are awesome radios. I thought the cord was basically just a buddy box cable.

[JosephS]

Keep going

These are awesome radios. I thought the cord was basically just a buddy box cable.



MagnumSenior.jpg

From the wiring it sure looks that way.
The controller and batteries are a heavy combination. Moving the batteries would make this lighter, though unbalanced.

It’s shocking how well built it is.

It seems to be a bit more involved than I would like just to move the case plastics.
The main problem on the new acquisition seems to be the throttle pot. It is sticking. I will try some plastic safe electric cleaner and see if I douse it if it frees up.

It was missing a bunch of screws when I I opened it up making me think that someone opens this up before me. I’m going to guess it doesn’t work. That would go along with the $30 price.

[juicedcoupe]

The main problem on the new acquisition seems to be the throttle pot. It is sticking. I will try some plastic safe electric cleaner and see if I douse it if it frees up.

I have two Magnum AM transmitters, both have the same problem.

[JosephS]

The main problem on the new acquisition seems to be the throttle pot. It is sticking. I will try some plastic safe electric cleaner and see if I douse it if it frees up.

I have two Magnum AM transmitters, both have the same problem.

Were you able to fix them?

[juicedcoupe]

The main problem on the new acquisition seems to be the throttle pot. It is sticking. I will try some plastic safe electric cleaner and see if I douse it if it frees up.

I have two Magnum AM transmitters, both have the same problem.

Were you able to fix them?

I didn't get aggressive but I tried some electrical contact cleaner. It didn't help.

[Dangeruss]

The new one was in rough shape with a lot of oxidation on the metal parts. As well the trigger was sticky.

Sticky like you pull the trigger back/push it forward and it's sluggish to return to center?

If so, working the trigger back & forth for several minutes usually free's them up. May takes a couple sessions. The grease used to dampen the trigger congeals over time and the back/forth motion restores its fluidity.

[CalPolyME]

I know this thread it old, but I had a similar issue with a trigger that would not return to center. My issue was the potentiometer was seizing. I scavenged a throttle potentiometer from another Futaba radio that was functioning well. The radio was a different model (don't recall which one), but it used the same potentiometer as the 3PG. I just de-soldered the old one and soldered in the replacement. It worked great. I've noticed a few things about older Futaba radios: (1) they used high quality components, (2) many of the components were common across different radio models. I have a few disassembled Futaba radios that I keep for parts scavenging when I need to repair or restore one of my good radios.

[JosephS]

I know this thread it old, but I had a similar issue with a trigger that would not return to center. My issue was the potentiometer was seizing. I scavenged a throttle potentiometer from another Futaba radio that was functioning well. The radio was a different model (don't recall which one), but it used the same potentiometer as the 3PG. I just de-soldered the old one and soldered in the replacement. It worked great. I've noticed a few things about older Futaba radios: (1) they used high quality components, (2) many of the components were common across different radio models. I have a few disassembled Futaba radios that I keep for parts scavenging when I need to repair or restore one of my good radios.

Thanks I haven't fixed this yet this may help. It's going to be a while before I get to this project.

I may have different generations of Futaba radios. I found very few of the parts seemed common between my t3pg and my newer model magnum junior.
I do agree it feels like a high quality build in taking this apart and putting it together.

Doing a quick internet search on how to fix a sticky potenimeter that the best thing to do is replace it.

Deoxit makes a compound F-5 just for pots and sliders.
Regular deoxit seems to have a few recommendations, as well as contact cleaners.
Some reported that soaking in regular isopropyl alcohol can work as well.

Maybe someone else can chime in on what works.

Found an audio repair forum where someone went on a deep dive explaining how to clean vintage potentimeters

[JosephS]

I decided to tackle some of this tonight. I partially disassembled the one with a sticky trigger and used some rubbing alcohol while I worked the trigger back and forth; it freed up the motion.

I then decided to actually test out the radios. I have 1 set of working crystals, 2 working Magnum senior radios and 2 working Novak (Ner-2s and Polaris) receivers. They felt nice while I was using them.

My Futaba receiver wasn't working.

I'm missing a few screws for the cases and need to fabricate a replacement battery door. As well I disabled the rotation adjustment on both the transmitters disassembling them wrong.

The remote didn't seem happy with 8x 1.5v alkaline batteries the voltage needle hit top so hard it pinged. For the short time I was testing all seemed fine.

[GoMachV]

Seniors (and many other of that era) ran 7 AA with a dummy spacer or 8 nicad cells.