The International Cessna^® 170 Association

Anyone know of a shop to have a Jasco alternator repaired? All the big shops point me towards Quality Aircraft Accessory out of Tulsa Oklahoma. Only problem with that is they will only offer a bench test and exchange, no repair. My alternator is making voltage just fine but has developed and sequel in the radio/intercom that is driving my wife nuts. I hate to replace something that is working especially at $625 exchange. I've talked with the local shops and no one wants to touch it.

Send it to Jasco!

Jasco made by Sigtronics, owned by Hartzel sold all inventory and rights to the outfit in Tulsa. I'm temped to switch to plane power simply because parts are available, and most shops can perform an overhaul. But I see that some have had problems with plane power, so I'm not sure what the best solution is.

How about a noise filter on the alternator output ?

It's has one installed. I see they may have better ones available now. But the noise developed in the way home from Oshkosh, until that time everything was good. It been steadily getting worse since. I have another one on loan I could swap it out and try it.

jmurtap wrote:It's has one installed. I see they may have better ones available now. But the noise developed in the way home from Oshkosh, until that time everything was good. It been steadily getting worse since. I have another one on loan I could swap it out and try it.

May have a diode going bad. Also depends on what type filter you have. Electrolytics have a relatively short life.

This is the one installed

jmurtap wrote:This is the one installed

Cessna part number....probably pricey. Make sure you check your battery terminals, alternator output lead and any of your other power connections for cleanliness and corrosion.

You might try Georges Electric in Sacramento, CA. They are a FAA certified repair station and mjight be able to help you.

It all looks good Ed, I gave George a call he said no go on Jasco's.

You might try calling Quickstart Electrical in East Peoria IL 309 694 3800 or Harvey Brothers in Galesburg IL 309 342 3137. Both have been around many years and do good work.

I am of the opinion that noise filters are just a bandaid for either a poor installation or parts going bad. If it starts making noise in the headset, it could be one of several things, including but not limited to: a loose ground somewhere in the system, alternator diodes going bad, regulator going bad, etc.

In closing we pulled the alternator to force a result in our radio noise. After pricing out a overhauled unit, we disassembled my current unit and found nothing wrong. So in desperation we installed a capacitor, a new larger filter, new seals and rubber on gear drive, new tach seal. While waiting on parts I was digging through the logs and discovered the main leaf spring hadn't been changed since 75, so while I was down I pulled the springs and discovered a healthy stress riser. So new springs and hardware were in order. Since the tailwheel was off.. hmm might as well clean, inspect and repaint that as well. Ohh what the heck lets put on new chains and springs too. So after all this got back together, we do a ground run, and guess what the dang noise is still in the radio.. A local pilot building a RV14 whom had many years in the audio industry said very plainly it has to be a ground. So I start rechecking grounds and every time I'm under the panel I get disgusted at the wiring, old wires cut and left there with new tied right to the old.. Anyways I digress, all the grounds seem to be making good continuity with the fire wall and the firewall make good continuity with the engine block and the alternator. With no hope left I detached and cleaned every ground I could find, (several as they just ground to anywhere). I also cleaned all the coax antenna leads under the dash. After which a test run resulted in a crystal clear and quite radio. Not to get my hopes up, during this run I was having trouble with my landing light fuse again, after which I found the problem with a bad solder joint. So today I fixed the fuse holder and the weather finally agreed it was a good day to have a test flight. I'm very delighted for the first time in 7 months there was absolute no alternator noise, the radio was crystal clear and quite. Now if I only knew what the final fix was!! This simple problem took on to be a lengthy project that I'm very glad is over and working properly!! Thanks for all you input!! Now back to enjoying blue sky's!!

Hip bone leg bone syndrome is hard to avoid. I finally got things situated with my panel upgrade/repair, and it was great to know the airplane a little more, but scary to see some of the crap that's under the panel. The oldest wiring was the best wiring, unfortunately. While I hate you had so much trouble, if a very nice airplane like yours has similar issues to mine, I feel a little but better, because I know your airplane was well taken care of for a long time.

The "not sure what actually fixed it in the end" is frustrating to say the least.

Jason, you seem to indicate you think the whine came from the bad solder joint. Did/do you fly with your landing light on all the time? Did you fly this test flight with it on?

If turning off the landing light, when the whine was present, didn't eliminate it, then the solder joint didn't cause it.