Stall warning failure

[rusbac]

I recently replaced my buzzer with one approx 85dB. It seems slightly quieter than the original, however it's hard to judge because the new buzzer is also noticeably higher in pitch.

If I need to repair/rebuild the buzzer. Any idea how loud (dB) a replacement ought to be?

[rydfly]

Christine, that's good to hear (pun intended!)

Can you share where you sourced your replacement?

I recently replaced my buzzer with one approx 85dB.

[rusbac]

https://www.radioshack.com/pages/search ... %20buzzers}
(Sorry the link won't play nice)

I can pull my receipts for the exact part number if you'd like. But I just went to the store with my housing in hand, and picked the unit that fit the best and had the correct voltage. My indicator light never stopped working which made it very easy to isolate the problem to the buzzer component itself.

[rydfly]

Hopefully I'll find something simple to correct with my original. Otherwise, I may have to make a quick trip to Radio Shack... as in REAL quick because ours has a "closing forever" sign in the window right now and I think they're all about to disappear nationally!

Thanks for your quick response.

-Kennet

[rydfly]

So I removed the stall warning unit this evening and checked for continuity across the posts. There was none. Also, the light bulb was burned out.

I disassembled the unit, separating the light assembly from the buzzer component. I checked continuity between the single-strand copper wire that ran from the positive-marked terminal into the buzzer and the body of the buzzer itself (including at the screw hole where it grounds to the housing when assembled). Again, no continuity.

Figuring I had nothing to lose, I used a 12V motorcycle battery as a power source, connecting to the single-stranded wire and the screw hole at the center rear of the buzzer... it sparked and the buzzer gave a brief noise, then silence (and no more sparks). After that, there was nothing I could do to trigger it again.

Now I REALLY have nothing to lose... so I pried all the tabs apart and opened it up. It looks like that single stranded wire runs all the way through it, connecting to what I assume is the mechanism that vibrates when electrically excited. However, when I check for continuity between the wire on the outside and the soldered terminal on the inside, there is none.

I realize this may be tough to visualize without pictures, but from what I've described, should there be continuity in this last place I checked? Also, is it possible that my motorcycle battery fried this thing? I would've thought it would be ok given that it's a 12V system that it operates on.

I was surprised that this buzzer is wired with only a single strand of copper wire given that it's connected in parallel with the light assembly which uses a heavier gauge multi-strand wire.

-Kennet

[Bruce Fenstermacher]

No, your motor cycle battery did not fry it. This is a 12v buzzer and in actuallity probably has a range of 6v-18v. You just happened to make your broken wire contact.

FYI, your airplanes electrical system is 12v which actually means it runs between about 12.5v and 15.5v depending on the state fo charge of your battery and adjustment of your voltage regulator. Your motor cycle battery at peak charge could be a little over 13v and probably 12.5v. Basically your car, motor cycle, lawn tractor and airplane have the same battery voltage and characteristics, just different sizes of capacity.

Replace the single strand wire with another wire which can be larger than the original and if you had your choice, fine stranded wire. Your buzzer should work.

Please please take pictures of your buzzer and the inside. It is rare that anyone takes them apart, except for me and I've only taken those apart from Lionel trains. I don't have, and never have had, a broken horn from a stall warning.

Please take lots of pictures and sent them to me to my email full at full resolution so I can post then for you AND use them in a print article on how to repair them. (btw whether you figure out how to post pictures here or not, they won't help for my printed article, full resolution pictures emailed is the only way that works for that)

Thanks

[rydfly]

Done, Bruce! You should have a series of emails with about 20 pictures or so. I'll let you post some of them here if you want. I'm going to attempt surgery on this thing later this morning. I'll keep everyone posted on the prognosis.

-Kennet

[GAHorn]

Kennet..... if your buzzer does not work.... contact me. I have a solution for you.

[GAHorn]

I just wrote a short article with pics and sent it to Bruce for possible inclusion in The 170 News regarding this repair. Hopefully it will help (presuming the pics are of sufficient quality....I've posted a couple of pics with this msg to give a preview) I replaced the horn-capsule with an near-identical unit and it works/sounds virtually identically.
If anyone's indicator-horn instrument has failed, feel free to contact me regarding possible repair options.

[vaflyer]

I'm in the same situation. My light works but the buzzer has stopped working! Sent a direct message to gahorn but appreciate any help.

[170C]

One of our TN members just experienced an issue with his stall warning buzzer. Turned out it was a bad ground. He got lucky.
Hard to find 60+ year old equipment still in tip-top condition

[N2625U]

Will yours work if you move the tang on the wing? Had a problem on my 172 with the electric stall buzzer. It would work on the ground when moving the tang but not in the air. Electrical contact cleaner did the job.

[lowNslow]

Just wondering if the problem is the capacitor as those old paper/foil ones are notorious for going bad with age. A neighbor of mine used to restore old radios and said you always replace all the capacitors and just some of the tubes. If that's the case, you could keep the original sounding horn.

[rnealon1]

Reviving another thread, my stall warning horn stopped working also. The light still works.

The back of the indicator/horn unit has terminals marked 12V and W as opposed to + and -. Is 12V the positive?

Bob

[cessna170bdriver]

Reviving another thread, my stall warning horn stopped working also. The light still works.

The back of the indicator/horn unit has terminals marked 12V and W as opposed to + and -. Is 12V the positive?

Bob

I have a new replacement buzzer that George Horn gave me that I never used, as my problem turned out to be with the switch. If you verify that the buzzer is bad, Let me know and I’ll forward it on to you.