Servos, what works with what, Why, Why Not?
 

I acquired a GP CUB-60 a few weeks ago, it had a Tower System 3000 radio and 5 servos. 1 Futaba S3003, 1 Futaba FP-S148, 1 Hobbico Command CS-51, 2 Tower System 2000 TS-51. I charged the depleted battteries overnight and turned things on, IT WENT NUTS. I had seenthis before when I tried to use a FP-S148 as the throttle servo with 4 S3003 servos, had to buy another S3003. In this case I took out the S148 and the system still had the gitters. I next removed the S3003 and still the problem, next the CS-51 and the remaining 2 TS-51 were Okay. I went ahead, because I had the time and interest, and checked the S3003 with my plane which had all S3003 servos, it was fine. I had some Command CS-51 in a bag on the wall so I tried the CS-51 with a set of CS-51s on the System 3000 receiver- Worked fine. I found 3, FP-S148s on a servo tray from an older plane, I attached all of them, plus the one from the CUB to the System 3000 and again all was fine In each case if I put any one of the other Servos in the mix, the whole system got the gitters. I thought that sometime ago the manufacturers decicdet omake things compatible but perhaps it is a generation gap thing. Maybe all Servos from one era are compatible but as technology has advanced, differences have by necessity appeared.

It someone with knowledge of this could provide information I would appreciate it greatly. I resolved the CUB's problem by replacing all the servos with a set of old JR NES-517 servos, they all worked just fine with the Tower System 3000 receiver.

RE: Servos, what works with what, Why, Why Not?
 

I mix all kinds of servos together Futaba, JR, Hitec and even some Airtronics and have never had a problem. Naturally the plugs must be compatible.

Bill

RE: Servos, what works with what, Why, Why Not?
 

Mixing and Matching is something I've done, in the past, also. Even with Airtronics servos it was just a matter of lead swaping at the connector and they were fine. As I indicated I have seen the problem with FP-S148s and S3003s both by Futaba. I expect to use all of the servos, I removed from the CUB, just not together.

It has only been in the last two years, that I've seen the problem, hence my question, WHY NOW. There has to be some incompatibility for some reason and it is not as simple as, "Gee the servo must be Bad" or "Maybe it's your receiver". Is it possible the S3003 expects a different pulse width or something and the FP-S148 cause some interference with that or visaversa? I can't believe I'm the first or only one to see this problem.

RE: Servos, what works with what, Why, Why Not?
 

simitar1,
It sounds like this is an old system that you picked up. The receiver battery may be weak or bad. Check the voltage. If you don't have a voltmeter,connect just one servo to reduce the load and if it gets better the battery may be the problem. Also check the wiring.

Dave

RE: Servos, what works with what, Why, Why Not?
 

The Battery was load tested with 500ma load versus normal 250, with an Ace Accu-cycler I even removed the Transmitter battery and checked it. All the wiring is the same and works great. All the obvious has been investigated twice over. With the total change to matching servos it range tests with the antenna down to better than 100 feet.

I've been in the hobby since 87, I'm retired from GM where I was a Systems Tech repairing, at component level not just a board swapper, (the good old days) computer circuit boards, Video systems, Laser scanning equipment, Printers, monitors and the occasional garage door open or TV remote. If I put the setup back as it was, as I did say I had, it gitters. I've removed different servos to see if it was just one or even two, it is any combination of that group.

RE: Servos, what works with what, Why, Why Not?
 

A Systems Tech would want to clearly define “… it gitters …”.

Bill

RE: Servos, what works with what, Why, Why Not?
 

Your problem is quite certainly not the servos. It has to be connectors, wire size/length, battery capacity, wiring but not the servos. If you are a tech, it is quite simple to examine the servo circuitry and see that they are all essentially the same design and most even use the same chips.