Strobe Tuner Repair?

[the elephant]

I have an ancient (and quite excellent) Conn ST-2 single wheel strobe tuner that was made when dinosaurs roamed the planet. I would like to have it rebuilt using new caps, bulbs, a cord, and other fun stuff.

I know that Peterson used to do this service. Anyone else? Does anyone here know these and want to make a buck? (I would rather ship this to someone I "know" than some large company that would rather I dump it to buy one of their strobes. I am sure that Peterson would love it if all the remaining Cone strobes would disappear, if you get my drift.

Anyone here ever had a Conn strobe rebuilt? Is it expensive? Can I do it myself? I have some electronics soldering chops and a very good Hakko iron, but I cannot read a schematic, and am an idiot regarding all the components.

[tadawson]

I did a bit of digging, and these things look pretty simple.

As far as rebuild, I would think caps, the pilot light, cord and test the tubes (replace if needed) and a good cleaning would do it.

The orange lamps on the wheel are neon tubes, and unless they are starting to not light, myself, I'l leave them, since there really isn't anything to burn out in a neon lamp (that, and not sure how easy they would be to find).

I don't think this would be very hard to work on if you have vacuum tube equipment and test gear that can handle the voltage.

If not, I'd be very leery, since it looks like there is 600 volts in the ST-2.

Is yours having any problems at this time, or just looming to freshen it up?

- Tim

[gocsick]

I am actually kind of surprised you can't just get a rebuild kit with the caps and tubes on eBay. I'm currently rebuilding a Seeburg jukebox.. and basically every module in the thing has a pack of all the current equivalents of the vintage components. There is even a guy in the Netherlands who custom winds transformers to give you so the right taps for the different voltage you need. Save for some old radios I've done on the past. I guess strobe tuners are just too niche.

[the elephant]

@tadawson

Lights up. The wheel spins. Nothing registers. I have two of the correct mics, and neither works, so it must be in the unit itself. I do not have *any* testing equipment, as I said, electrical idiot, but I used to assemble and test circuit boards. But no real knowledge is needed in an assembly plant; just follow the instructions you are given. I can do the work. I do not *understand* the work. I know about the 600V, though. I have good soldering tools, as I have bodged several Mac mobos in the past and have recapped an SE/30, but that is just simple parts swapping and not diagnostic work. I have a Fluke meter, but do not really know how to use it for something like this.

[the elephant]

@gocsick

Had no idea rebuild kits like that even existed. I'll have to look, but I assume there are no such kits. The existence of such kits—to me—implies a thriving rebuild community, and there is not one for strobe tuners, so far as I can tell.

Peterson bought out Conn's division that used to make tuners back in 1985, and used to handle all service and repairs. I do not know if they still honor this. I sent them an email, and I'll see what they say.

Until then, I am left to look at the massively huge components and wires (not a PCB, IC, or even an old-style transistor in sight—this thing is fully Post-WWII technology) and think that I could *easily* do the work myself… if I knew how, if I could source the parts, etc.

I'll scour eBay to see if such a kit exists right now. Thanks.

[gocsick]

You really need an oscilloscope to troubleshoot...

What immediately jumps to mind... since you are not getting any response at all.. but it is spinning up

Faulty preamp or comparator circuit

Bad op-amp

Signal not getting to logic that drives the strobe ring

Oscilloscope really helps here to trace the signal path and visualize the input waveform.

Without some experience reading the prints and having at least a $99 Amazon scope/meter... I think your original inclination to find someone do it for is the right one.

[the elephant]

Yeah, but WHO? Most YouTube videos are hobbyist radio guys who look at the schematic and the layout and are confused by what everything does (and why); it's just a cool, old tube-driven device that has a radio vibe to it that they picked up at a garage sale for a few bucks.

I found one guy who seemed to understand how it works and how it is used. I can never figure out how to contact YouTubers, though, except through comments, and no one seems to ever read my comments.

[tadawson]

Trying to figure out my free time, but what you describe is on the simple side of the circuit . . . one dual element tube, one preamp tube and about 16 other caps and resistors I see on a quick count. The wheel is driven, so sounds like the power supply and that side of the unit is OK.

Drop me a PM . . . I can take a look at it (and these are far, far, simpler that the stuff I normally work on). (But I did grow up on tube gear, so it's very familiar . . .).

(I was just asking condition because I didn't really want to take on a smoking hulk . . . )

- Tim

[bloke]

Trying to figure out my free time, but what you describe is on the simple side of the circuit . . . one dual element tube, one preamp tube and about 16 other caps and resistors I see on a quick count. The wheel is driven, so sounds like the power supply and that side of the unit is OK.

Drop me a PM . . . I can take a look at it (and these are far, far, simpler that the stuff I normally work on). (But I did grow up on tube gear, so it's very familiar . . .).

(I was just asking condition because I didn't really want to take on a smoking hulk . . . )

- Tim

If you're kind of a big deal, I have a early 80s 12-in polytone bass amp that drops out (volume) I'm pretty sure it's not the pots.

I don't know if you noticed but I put my really nice Fender bass up for sale and an Ampeg tube amp to go with it from the same vintage, but all the sudden I'm playing bass again and I would love to have this little amp working again. ...I'm not asking for charity.

[tubatodd]

@the elephant there's a guy on YouTube that has a channel called D-Lab. He does mostly old tube amp restorations. I would imagine he could fix a strobe tuner. In fact he might feature your repairs on his channel.

[1 Ton Tommy]

The most common failure on this sort of gear is electrolytic capacitors. They "dry out" if not used for a long period (that period being determined by build quality) and then when voltage is applied short out. Big ones are hard to test even with the capacitor check function on a Fluke meter -- I once worked in the division of Fluke that designed these things. You can assume the caps are bad, get the size of the cap off the cap itself and buy new ones, observing the voltage spec. They aren't expensive and are available from Mouser electronics amongst others. If you can solder it's not a difficult job. Some power-supply and output-coupling caps are cans that plug into the board like a tube and these can sometimes be expensive. They're mostly found on audio equipment.

There are other failures that are easier to detect such as: burned resistors (sometimes resulting from shorted caps); dirty potentiometers, rotary switches, contacts in plugs and jacks and so on. A can of electronic contact cleaner will work wonders.

Cold solder joints can also be a problem but more so on printed circuit boards. One can see this failure with a magnifying glass then heat the joint to re-flow the solder. This often happens from vibration, like on portable equipment or a bass amp. I think your strobe would qualify as portable and maybe subject to vibration or physical shock.

Most vacuum tubes are available either as NOS or reproductions. Russian tubes are common.

[tadawson]

Trying to figure out my free time, but what you describe is on the simple side of the circuit . . . one dual element tube, one preamp tube and about 16 other caps and resistors I see on a quick count. The wheel is driven, so sounds like the power supply and that side of the unit is OK.

Drop me a PM . . . I can take a look at it (and these are far, far, simpler that the stuff I normally work on). (But I did grow up on tube gear, so it's very familiar . . .).

(I was just asking condition because I didn't really want to take on a smoking hulk . . . )

- Tim

If you're kind of a big deal, I have a early 80s 12-in polytone bass amp that drops out (volume) I'm pretty sure it's not the pots.

I don't know if you noticed but I put my really nice Fender bass up for sale and an Ampeg tube amp to go with it from the same vintage, but all the sudden I'm playing bass again and I would love to have this little amp working again. ...I'm not asking for charity.

Not sure what you mean by "big deal", but I've been working on stuff for 50 years or so . . . grew up in a small town with marginal repair facilities, so Dad DIY'ed and pulled me in. Took an EE degree and have stayed with it, servicing, designing, and building some custom stuff . . . mainly supporting myself and my sound and lighting business. Not much of a fan of surface mount stuff, but have the tools for a lot of that as well. Mostly for myself, but I do take on some outside work (it's neven been my full time gig . . . ) for friends and folks with common interests such as here, and I do have a fully equipped dedicated electronics shop. The biggest issue now is for bigger stuff like an amp, I'm way up in the UP of MI, so getting bigger stuff here typically requires shipping. If you have the model number of the amp, let me see what I can dig up on it . . . I'd certainly be willing to look at it, and to date, recall only one thing that I couldn't fix in all those years. Heck, were we closer, I'd consider meeting . . . I'd like to get some rebuild work done on my 1970's Mirwfone 186 . . . :-) :-)

[bloke]

@tadawson

"Big deal" just means knowledgeable and competent, in this case.

It's more expensive and more risky to ship a 186 than a 13x13 amp (though heavy). If you came down here when the summer repairs are gone and on a day or two that I have no gigs... or at least they are at night or something... I'll be glad to work on a 186 while you are here.
Otherwise, I would be otherwise putting this little amp to use around twice monthly even before you might manage to get here, so I wonder if I could ship the amp to you and you could bring it back down here along with your 186 when the hottest weather is gone and all of the school repairs are back at the schools...??

We put up people who drive here from a distance and feed them, so all they lose are their fuel costs for driving... And we encourage people to come down here in their smallest vehicles to save gas, but that's up to them.

I've done here to Interlochen (back when I was much younger) in 12 hours flat. I drove at insane speeds that I would not recommend. If you live in southern Michigan (??), maybe you could actually get here in 12 hours flat at reasonable speeds that aren't much above the speed limits...??
(Hotels are nasty and expensive.)

extraneous information:
I sort of forgot that I have a Roland cube-60 ($30 pawn shop find during the most draconian portion of the economic shutdown) that works for bass if the volume is not turned up to 11. It's nowhere near as good as the 12-in polytone bass amp, but it might do until the polytone is made to work again. It would be amazing to have that old polytone working as it should. I actually have two OEM speakers for it. I have a heavy-ass Peavey with a black widow, and I even have a behemoth Woodson (same guts as Kustom) PA with two columns (4 X 10" + 4 X 10")... but there's no way that I'm dragging either of those to some little jazz combo gig.

(I actually use the PA to practice playing along with a recorded piano accompaniment or symphony orchestra, as it's all I have that can really crank as loud as those real instruments can actually crank without distorting.)

I think it would be really cool if you can get Wade's strobotuner fixed. I picked up one of those a long time ago and could never get the motor to work right. I later ended up with a Peterson with a little TV screen thing that works perfectly. The Peterson and the Woodson PA were actually stuff tossed in the pile with a whole bunch of band instruments I bought.

[the elephant]

I am considering joining a local vintage radio club (for home tombstone radio receivers from the 1920s and 1930s, not a HAM group) because they all know a small amount about tube technology and where to get parts. I am hoping to drag this old tuner to a meeting and get some lessons on how to source parts and how to diagnose issues on such old gear. I want to do a complete rebuild of this with all new (or as many as possible) parts, save for the two neon bulbs, which seem to be very difficult and expensive to source today. Both of mine light up fine, and neon bulbs of this type rarely go out. You pretty much have to damage them to kill them.

So maybe this will be how I attack this project. I certainly do not need to ship this off anywhere as I already own something like four digital tuners and some phone apps. A real strobe is superior, anyway. and I prefer to learn by doing, as they say (whoever "they" might be).

[bloke]

If it's okay to continue to barely broaden the topic - as I did regarding my bass amplifier...

... I actually own another pretty amazing Peterson made item, which is the first tuner they ever made, and it is vacuum tube operated. It does not have a dial and doesn't mechanically show the user when their instrument is in tune, but basically it's an electronic tuning fork which emits tones, and was mostly used by organ pipe tuners to tune organ pipes whereby they would match the pitch of the organ pipe with the pitch emitted from this device.
I believe the fact that it is loud helped those people hear both the pipe and the tuning device, as it's much louder than any tuning fork.

Apparently, these things are rare as hell.

I don't need it, but it's really cool.

It's still sort of works but I think some of the tubes might be a little weak.

I don't pull it out and mess with it.
After all, what would I really do with it other than to show it to somebody?

Most people here have figured out that I'd really don't collect things and tend to sell stuff that I don't need or use.
Of course, I hold on to pictures of family members and little things that people I love have given to me... But I'm not a person that buys "vintage Lionel train outfits" or any of that sort of thing... And you also probably have noticed that I'm not a collector of tubas even though I have quite a few - but those quite a few each have specific gig purposes.

I think it would be pretty nice to have this Peterson thing working just as it should, but once it was made to be like that, it would probably just be set on a shelf and collect dust and corrode...

I'm not going to sell it, because a friend/colleague/former student gave it to me and - when he did so - he told me that it was in appreciation for things I had done to help him over the years. I was sort of shocked, because I really couldn't think of that many things I had done for them...but apparently what I did do meant something to them, so this gift of this super rare Peterson tuning thing means something to me. Maybe I'll post a picture..
(??) ... If I ever did get rid of it, I would probably give it to someone who [1] really really wanted it for their collection, and [2] whose help in my life has really meant something...but - right now - I just don't know if someone who fits in the middle of that two-circle Venn diagram.

[the elephant]

Conn made one of those waaaaay back in dinosaur times, called the Lectro Tuner. I think that they had already discontinued it by 1985 when Peterson bought them out. I suspect that Peterson knew of this device (or stumbled across an old one) and decided to reintroduce it to the market. I agree, they are useful, if not a little deafening, as a very good drone pitch generator. You can indeed hear it clearly as you play. In fact, I seem to remember the beats it produced for me were against my forehead, and something you had to be stupid to not correct as you played. Here is one on eBay. I am not sure this is the same thing you are talking about, but I seem to remember the one I used being for organ tuning using beats, and we used it in my HS band on occasion, when individuals suffering from "the stupids" took over a rehearsal.

CLICKY!

[bloke]

Google tells me that Peterson's first "chromatic tuner" (tone generator - ie. this thing) dates back to 1948...
...but I can't find picture-one on the internet (other than the one I'm about to post below), because they're stupid-rare.

...so on top is my OLD Peterson chromatic tuner, and - underneath it - is Peterson's very FIRST chromatic tuner.

I paid zilch for the pair.



The 450 - yes - has a black cabinet.
(noticed: When the cabinet IS black, it's mentioned in for-sale ads.)

The Model 450 is considered a rare and sought-after item, particularly the black models from the 1990s.

...and (again: background) I was just checking out my nearly-free Roland Cube to see how well it works as a bass amp Friday night (silly little jazz quartet gig)...
...I'll be able to make it work - turned up to mid-volume, with the treble at about 1-1/2, the mid-range at about 4, and the bass cranked most of the way up (round sound, and enough articulation - even with my antique flat-wound (though - oddly - still just fine) strings.

The plastic over the Peterson strobe display isn't broken...I have no idea what the phone camera was seeing...(??)

[tadawson]

@tadawson

"Big deal" just means knowledgeable and competent, in this case.

It's more expensive and more risky to ship a 186 than a 13x13 amp (though heavy). If you came down here when the summer repairs are gone and on a day or two that I have no gigs... or at least they are at night or something... I'll be glad to work on a 186 while you are here.
Otherwise, I would be otherwise putting this little amp to use around twice monthly even before you might manage to get here, so I wonder if I could ship the amp to you and you could bring it back down here along with your 186 when the hottest weather is gone and all of the school repairs are back at the schools...??

We put up people who drive here from a distance and feed them, so all they lose are their fuel costs for driving... And we encourage people to come down here in their smallest vehicles to save gas, but that's up to them.

I've done here to Interlochen (back when I was much younger) in 12 hours flat. I drove at insane speeds that I would not recommend. If you live in southern Michigan (??), maybe you could actually get here in 12 hours flat at reasonable speeds that aren't much above the speed limits...??
(Hotels are nasty and expensive.)

extraneous information:
I sort of forgot that I have a Roland cube-60 ($30 pawn shop find during the most draconian portion of the economic shutdown) that works for bass if the volume is not turned up to 11. It's nowhere near as good as the 12-in polytone bass amp, but it might do until the polytone is made to work again. It would be amazing to have that old polytone working as it should. I actually have two OEM speakers for it. I have a heavy-ass Peavey with a black widow, and I even have a behemoth Woodson (same guts as Kustom) PA with two columns (4 X 10" + 4 X 10")... but there's no way that I'm dragging either of those to some little jazz combo gig.

(I actually use the PA to practice playing along with a recorded piano accompaniment or symphony orchestra, as it's all I have that can really crank as loud as those real instruments can actually crank without distorting.)

I think it would be really cool if you can get Wade's strobotuner fixed. I picked up one of those a long time ago and could never get the motor to work right. I later ended up with a Peterson with a little TV screen thing that works perfectly. The Peterson and the Woodson PA were actually stuff tossed in the pile with a whole bunch of band instruments I bought.

Not a problem! If you think the amp ship OK, I have no issue with that. I am actually in the upper peninsula of MI, and the northern part of that (lake Superior on 3 sides), so Interlochen is about 395 miles out . . . On my 186, it's playing pretty well, but was bought as a bargain horn, and is a bit ugly, and has some dents in the bottom bow and branches that the local guy can't get to, and I've been considering a refinish, so likely more than a couple days, but have not made the call. Were on on I-35, we travel back to TX for family stuff, but that's about it (and the only place I know on the way is Denton Big Brass . . . and, ironically, I lived about 15 miles from them before moving . . . ). Still kinda trying to decide what I want to do with it, cast, etc.

I'm glad to work on Wade's tuner as well if he wants to ship it. That circuit really is simple . . . and the main proprietary part (the motor) sounds like it is fine. (The key thing there is that it is a synchronous AC motor, and the note selector knob basically sets a tone generator to a pitch for the selected note, and that is amplified to drive the motor. If you still have yours, short of the motor being physically damaged, I would think that wouldn't be that bad either.

Now that I'm talking bass amps, I ought to dig one of those out as well. The organizer of our long lived comminity band seems to have gotten lazy this summer, as well as not telling anyone so that someone else could step in, so we aren't playing . . . grrrr . . . Got some friends who could probably use an electric bass player, so who knows?

[bloke]

In that case, likely 900 miles...(very hard one-day, but easy two-day drive)

If you were DRIVING to Texas, you could stay over one night (here) get fed, I could hussle out some work on that 186 (maybe an afternoon plus a next morning) and you could drive on to Texas that day...but (again) shipping a 186 isn't advisable...at least not in the USA (expensive/careless handling).

[the elephant]

I'm glad to work on Wade's tuner as well if he wants to ship it.

Much obliged, sir. I'll surely contact you about it if I cannot take care of it myself.