Our division received a Roanoke Electronics Super Horn as part of a estate donation. This is definitely old school, as it consists of a sound unit that has an attached speaker and a 12 V dc wall wart to power it all, despite the labeleding on the back that says it requires 120 VAC.
The unit has a switch that allows choice of Steam or Desel sounds, but this one only has power leads to the Steam side.
It also has a bell switch with a choice of two rates of ringing.
A Volume switch controls that.
A 4-position Selector switch is said to control 3 different horns, plus an Off setting. But there's no horn despite a 2 position selection swicth offering Long and Short horns(plus Center Off) -- almost.
While rehabbing a number of flaky looking solder joints and generally looking it over, I managed to bump it just right a couple of times and the horn sounded! So the various intergrated circuits seem to be OK, It appears to be some sort of control circuit issue.
The horn switch feels solid and nothing else suggests the any of the other switch hardware has failed. There are no obvious caps leaking or other signs or a failure point.
I'd like to get this working, but there's little out there on the internet about it -- it's definitely pre-internet circa 70s-80s. It would be great for kids to be able to toot the horn or ring the bell , assuming we don't have to cancel mnext year's local train show of course.
Anyone have a suggestion about how tio get this relic working again?
Mike Lehman
Urbana, IL
Probbaly start by spraying some contact cleaner on the rotary switches and running them back and forth a few times. I found a picture of one on an auction site, assuming it's the same fevice - if that 'activate' toggle is a momentary toggle, you can try shorting the pins on it to mimic the switch closing to see if it works, that would point to that switch being bad, or flakey. Contact cleaner may help. Same with the little selector toggles.
Pic of the back shows it has a wall wart power supply, an audio out that I guess can feed a speaker directly, unknown wattage requirement, and a line out that can plug in to an amplifier.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Hi Randy,
Oops, sorry you had to look up the pics, as I'd intended to include a couple, but got busy and neglected to do so. Here are pics of the front and back of the Super Horn.
The little window that says "SEC" or something like that suggests an infra-red sensor behind it, but nothing obviously like that on board. We have a small wirelss throttle that appears to be infra-red, but no obvious base station, so kind of don't know what to make if it.
I tried to bridge the Horn switch contacts and no joy. Then I remembered I'd also forgotten to note that a set of paired voltage regulators were running hot and after accidentally bumping the contacts on one of them dfiscovered that would make the horn toot!
I suspect that the bad VR is behind this. I didn't find a circuit diagram, but will see about tracing things over and about getting a pair of these VRs and new caps to go with. It was bridging the poles on one of the VR caps that leads to a toot.
Thanks so much for the nudge in the right direction.
Probably just have a bad cap then. The VRs are probably fine even if they did get hot, most will shut down in overheated to save themselves.
If one's bad, more might be. Electrolytics with an unknown storage history are probably suspect. Ones in the sound generating part of the circuit will just make it sound odd, but in the power supply section, they can kill the whole thing. Also look for any of those little blob tantalum caps. They were often used as power filter caps back in the day and tend to fail rather dramatically.
OMG ! - I still have one of those packed away in a box somewhere ! I also built Keith Guterez (sp) SDX-1 diesel sound system to go with it that was published in MR eons ago. It was pretty high-tech stuff at the time.
Mark.
¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ
rrinkerThe VRs are probably fine
Yes, they did seem to check out once I put the meter to them. The hot one is the middle one, which shares a heat sink with the innermost one. They seem to be back to back, one is +5v and one is -5v. The outermost one seems to be 12v.
A view of them from the side, somewhat askew after I replaced the 10uf cap with a 100 uf (closest I had)
Top view of same area
A top side vew. The big cap is another I replaced, subbing a 4700 uf for a 3500uf.
rrinkerlook for any of those little blob tantalum caps. They were often used as power filter caps back in the day and tend to fail rather dramatically.
Most of the small orange blobby ones I think you're referring to are to the right in the pic above. Here's a better loo at them from a different angle.
None look obviously failed, but as you say the do fail. I don't have enough to just start subbing for the ten or so present. Is there a test that tells you if they're good or not?
Finally, underneath the voltage regulator location in the first few pics are a pair of jumpers. They may be factory as they use the same wire as some of the gavtoruy wiing, but they are a bit odd being the only wires on the bottom of the board.
To the right of the purple wires are the yet uncut legs of the cap I replaced at the middle VR that is askew in the first few pics. If I jumper them with a screwdriver the horn blows.
The blobs I see in all the pics are ceramix caps, those are OK.
Seems strange that jumpering over a filter capacitor makes it work. Unless there is a damaged trace.
Randy,
Yeah, good to hear nothing is likely wrong with those small disc caps.
Those purple jumpers are interesting. In the pic, they emerge on the lower side of the board from the lower two points that are fed from right next to a black box on the top side of the board. It's labeled R3203L and has a diode marking on it (and I was unable to google anything on it), with + and - sides feeding the big 4700 uf cap. It is fed directly from the incoming switched power circuit.The 4700 cap's legs where the other two ends of the purple jumpers are soldered to are then in turn soldered to the two + and - minus traces that feed the voltage regulators in line above, including the one that gets hot.
The traces where the pruple jumpers attach to seem undamaged, so maybe it was a structural reinforcement to carry each leg over and solder it again to the bus traces that feed the VRs.
I tried cutting the 4700 cap legs that are bent and seem redudant, but that kills the bell, so they are needed to make the thing function, I suspect the problem is after this section of the board so will do some more tracing later today and report back.
Thanks!