Stall warning failure

How to keep the Cessna 170 flying and airworthy.

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GAHorn
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Re: Stall warning failure

Post by GAHorn »

rnealon1 wrote: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
‘If it “stopped” working... it implies that it Once-Worked... so unless you’ve switched the leads..... :wink:

(Either way, you can use test-leads and try it each way and soon find out. Reversing them will cause no harm.)
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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rnealon1
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Re: Stall warning failure

Post by rnealon1 »

Thanks George, I think I reversed the leads although I thought I marked everything carefully. Prior to my inspection the light worked but not the horn. Now neither works, and the bulb is good.

I noticed also there is no retaining ring for the light, it just pulls right out.

Thanks,

Bob
Bob Nealon

Southbury, CT
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GAHorn
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Re: Stall warning failure

Post by GAHorn »

Well, the lamp doesn’t have any regard for polarity, so this indicates (pardon the pun) that you have an internal wiring and/or grounding problem with the horn/light device. (Beware: Lamps are like fuses... looking at them doesn’t prove them. They must be tested for continuity.)
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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rnealon1
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Re: Stall warning failure

Post by rnealon1 »

cessna170bdriver wrote:
rnealon1 wrote: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.
Hi Miles,

I sent you a PM, but it does appear to be the buzzer and I would be happy to pay good money for the one you have.

Thanks,

Bob
Bob Nealon

Southbury, CT
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cessna170bdriver
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Re: Stall warning failure

Post by cessna170bdriver »

Bob, I just saw your PM a short while ago. I’ll put the buzzer on its way to you tomorrow.
Miles

“I envy no man that knows more than myself, but pity them that know less.”
— Thomas Browne
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rnealon1
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Re: Stall warning failure

Post by rnealon1 »

Does anyone know what the retaining ring looks like for this unit, that prevents the face from falling out of the case? And/or where to obtain one?

I actually have 2 units now. On my original, the face will not stay in. On the other, the face cannot be removed; possibly super glued or somehow corroded in place. Neither has any visible retainer.

Thanks!

Bob
Bob Nealon

Southbury, CT
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Hawkeyenfo
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Re: Stall warning failure

Post by Hawkeyenfo »

Does anyone have another buzzer lying around collecting dust? Mine hasn't worked since I've owned it (13 years now....)

Thanks!
Fly Navy !!!!

1941 Boeing PT-13D Stearman
1952 Cessna 170B
1960 Piper Aztec (PA23-250)
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GAHorn
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Re: Stall warning failure

Post by GAHorn »

Hawkeye, check your PMs.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
jrod270
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Re: Stall warning failure

Post by jrod270 »

Bump, how do you get these units apart? Also where did you guys get the replacement buzzer?
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GAHorn
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Re: Stall warning failure

Post by GAHorn »

jrod270 wrote: Sun Jan 19, 2025 10:17 pm Bump, how do you get these units apart? Also where did you guys get the replacement buzzer?
Which unit are you trying to disassemble…??… the bakelite cylinder with the lamp? …or the lift-detector.?

The bakelite lamp/horn assy is disassembled from the front by carefully prying the metal grill out of the bakelite cylinder. Inside is where the metal canister “horn” is located…usually held in place with a machine-bolt/nut thru the rear.

The canister horn is not available as individual parts AFAIK …. they can sometimes be repaired by working on the vibrating points and/or the capacitor which is found inside some units might be all that is needed…… but it might also be replaced with an “owner produced part”…such as a cheap metal buzzer/horn such as I supplied at the Deming convention. I may still have one or two if you contact me privately. :wink:

(the type horn I’m mentioning LOOKS exactly lie the one in this youtube video Bruce posted which explains how to repair these little type of horns)
https://www.youtube.com/watch?v=3LsDKsNBBKQ
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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TCU76109
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Re: Stall warning failure

Post by TCU76109 »

Since this thread was revived, and in case it’s news to folks here, Cessna sent out a Service Bulletin SEB-34-32 about stall warning horns in certain models of 182s, 206s, and 207s. It points out the original stall warning horn is no longer available, and they have a new bracket & horn. The horn itself appears to be a Sonalert-style horn, and the P/N is 9910080-5 at $294.

https://cessnaowner.org/wp-content/uplo ... 06-207.pdf

The diagrams are quite interesting.

This installation might provide some assistance to those looking for a basis to use a modern horn to replace a part that’s no longer available.
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rnealon1
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Re: Stall warning failure

Post by rnealon1 »

I have a working stall warning panel unit from my 170B if needed.

Bob
Bob Nealon

Southbury, CT
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GAHorn
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Re: Stall warning failure

Post by GAHorn »

rnealon1 wrote: Sat Jan 25, 2025 7:21 pm I have a working stall warning panel unit from my 170B if needed.

Bob
I hope you have one installed as well….. as per the TCDS it is “Required Equipment” on a B-model. :wink:
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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rnealon1
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Re: Stall warning failure

Post by rnealon1 »

:D

Yes I have one installed thank you. It is also in working condition.
Bob Nealon

Southbury, CT
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