Messages

Hmm, well check that the pot works, but otherwise it sounds like there are some bad or missing parts in the vibrato circuit.

TR-4 is the driver for the vibrato oscillator, that could have gone bad.

Other parts to check are C46, C53, R54 and D6, these couple the vibrato signal to the piano signal.

Further upstream, C27, C38, C44, and R32, R33, R43 form the rest of oscillator circuit.  C39 controls the AC gain of the vibrato signal.  This is also the cap to play around with if you do get the vibrato working and it is "thumpy".  If any of these parts have drifted far from spec it may cause the vibrato to stop working.

btw, the .12uf caps in the vibrato circuit can be sort of hard to find.  I tried putting .1 caps in when I rebuilt my amp and they caused the vibrato to stop working.  I could have probably played around with changing the values of the resistors in the circuit to get it in tune again, but the simplest solution was to hunt down the proper caps.  I found em on eBay - same seller still has a bunch: http://www.ebay.com/itm/370378550191

Good luck!

Are you certain you removed the jumper between point 12 and ground?  It might be on the back of the board; I have never converted a 206 so I don't know which side it is typically on.

A video could be helpful, or just some photos and sound clips.  There might be any number of things wrong with your piano which will give you headaches, some compounding or obscuring other problems.  For instance, the vibrato section of your amp may not even be functioning properly because of bad or missing components, and nothing you do with regard to the pot wiring will change that.

On a stock 206, there would be a jumper between point 12 and ground, have you removed that?  It shunts the vibrato signal to ground.

If so are you sure all the other necessary components for the vibrato are on the board?

Which resistor is connected to ground, the 2.2k or the 6.8k?  The suggested arrangement is having the 2.2k connected to ground (6.8k would be connected the the jumper installed at the edge of the board, and the common junction of the two resistors is where your aux out signal lead is connected).

If this is how you have it, you can attenuate the signal by putting a larger-value resistor in place of the 6.8k, or adding another in series with it to increase the overall resistance.  You can play around with the resistor values until you get the signal level you desire.

Also, do check the trimmer pot that is on the PCB.  That controls the preamp gain.  If it's turned way up that may also be heating up the signal. 

As far as connecting the trem pot goes, the wiper (center lug) goes to point 12, one outer leg goes to point 13, and the other leg goes to ground.  (refer to the PCB layout in the service manual for these locations on the board)

If the pot works in the reverse as is desired (clockwise turns off the trem), reverse the two outer leads.

Awesome!

Remember, there are a number of relatively easy things you can do with the 200 to cut down on hum before getting into the amplifier itself:

- 200A-style reed bar shields (huge improvement in RF hum reduction)
-  improved lead dress and shielding of the AC mains going to the transformer
- replacement of the neon pilot light with a DC-supplied LED - VV sells a kit but if you are savvy, all the parts are available elsewhere for under $5
- check all grounds for good conductivity, especially the RCA connection from the reed bar.

For reference, I'm looking at the output connections schematics on pg 45 of the full 200/200A series manual from the Vintage Vibe PDF (the big 81-page manual).

Judging by the 206 schematic I believe the 8ohm/5w and the 470ohm resistors are related to using the piano in the self and ensemble monitoring modes, which you can ignore for your purposes.

I think it is safe to disregard those resistors when hooking up a different speaker cab.  In a 200, the speaker signal is coming straight from the red wire at point 8 with no other components between there and the speaker (well, it does go to the headphone jack first, where it connects through the switched jack to the orange wire which goes to the speakers.)

Here's another question, do you still get the same problems through the aux out?

I may be wrong but I believe the aux out tap is in front of the output stage.  If that's true, you should be able to figure out whether the problem is isolated to the output stage or if is further upstream of there (or both!)

If you look at your existing speakers there should be an orange wire going to the + terminal on the speakers (or going to where the speakers used to be, if your 206 is missing the console).  In that case it would be the orange wire coming from one of the terminals of the rotary switch on the front panel (speaker/self/ensemble).

[Edit - the speaker signal comes into the rotary switch through a red wire which comes from point 8 on the PCB, which is to the left of C6, near some of the big power resistors - that's the most direct point where you can tap into the speaker signal]

That's your speaker signal.  You can tap into that for an external speaker jack.  The 206 was designed to see an 8ohm load - since it is a solid state amp I wouldn't go below that impedance too much or you'll risk frying your output transistors.

If you have the speaker console still attached and functioning, you might want to consider using a switching jack for your external speaker jack, and set it up so it disconnects the internal speakers when using an external cab.  This will prevent you from inadvertently dropping your impedance too low and frying the output stage.

Looking at the schematic again, the voltage from the negative side of C9 should be .6VDC.  From the positive side of C9 to ground, you should be seeing close to 23VDC.

The 44VDC should be coming from the positive side of C6.

The schematic calls for a 10k pot for the vibrato intensity control.  Not sure if its linear or audio taper, I would guess linear?  That's a relatively common value to find.

What you may have trouble with is getting the original knob to fit nicely.  For me, when I have had to replace or add a pot (in my case, adding a third knob for vibrato rate control), I had to carefully cut and shape the pot shaft with a hacksaw and file.   Or you could buy the ready-to-install pot from one of the Wurly parts suppliers.

By the way, do you have a copy of the schematic and service manual to look at?  The Vintage Vibe website has a PDF of the whole service manual for the 200 series (among other models as well), with multiple revisions of the schematic and PCB included.  It's a free download.

Are you certain you installed the new capacitor with correct polarity?  Putting it in backwards could have caused you some trouble.  Blowing the fuse means something in the circuit was drawing too much current.

Looking at the schematic, C6 supplies the +44VDC to the output section.  You may have fried some components in that part of the circuit, though hopefully not the output transistors.

Did you see or smell any magic smoke when you first powered up the amp with the 3000mfd cap?  If so, look/sniff around for toasted components.  Another way to help identify the problem is to check the voltages indicated by the schematic against what is actually going on in your amp.

FYI, I'm no electrical engineer - my experience with working on these amps is limited to a few bits of basic electronics knowledge and a good sense of logic.  But they are not terribly complicated either so don't be too daunted.   Remember to be safe when working around live voltages!

Yeah, those resistor values would definitely mess up your aux out signal.  The 2.2 (2.2K) is bleeding part of the signal to ground and having a very low value resistor there is going to kill the signal level.  It's like turning the volume knob way down on a guitar, allowing signal to go to ground before it reaches the amplifier input.

Personally, in my 200 I tried changing to the 6.8k/2.2k/no cap arrangement from the older 100k/15k/5mfd cap and I preferred the sound quality with the original layout.  So I went back to that but I also added a second 15k resistor in parallel with the 100k to boost the output level.  But that was only on my personal 200, your mileage may vary.

If you find that the 6.8k/2.2k setup isn't giving you enough output, you can also try swapping the positions of the two resistors, as suggested in the service notes.

Also, 1/2 watt resistors are sufficient.  I try not to use anything smaller than that in any audio application, but that is plenty in this implementation.

I agree - If I can get a set to measure or can figure it out from photos, I'll draw them up in AutoCAD and post it as a PDF.

Thanks - I figured they are probably near impossible to find.  Just finding a 140B that still has the fall cover seems fairly rare.

I can't imagine the hardware is very complicated or hard to reproduce though, so just a few good pictures would be an enormous help.  I can probably make something up in my machine shop if I see what they are supposed to look like.

I just picked up another 140B that I'll be restoring, complete with the legs, sustain pedal, and fall cover - only thing is the latch pins for the fall cover are missing.  Anyone got a spare set they wanna let go?  Or at least some detailed photos and measurements so I can fabricate my own?

Also the knobs are a bit dinged up, anyone got a spare set in good shape or know where to get some?

I've never used Simichrome for plastic but it is awesome stuff for chrome and aluminum.  Fantastic for chrome legs!  I used it on the chrome Z-stand for my Vox Organ and it made a huge difference.

Cool that it works on plastic too!

Regarding the color of the hammer tips, at least as far as bicycle/car tires go, black tends to last longer.  The color comes from adding carbon black to the rubber, which adds abrasion and UV resistance (UV is probably not much of an issue for Rhodes pianos though, unless you've got blacklight effects coming from under the hood!)

That's why tires are almost always black, unless they are for show or old-timey restorations.  Same with black sidewalls on bike tires vs. gum/tanwall, they don't crack and dry out in the sun as fast.

So I could easily see colored hammer tips wearing faster than black ones.

Interesting - Steve I did notice you recommended against dremel reshaping in a previous posting.  Obviously, Vintage Vibe are expert techs and can make a judgement about which hammers they can fix with a dremel and which need replacement, though it seems they endorse the idea pretty strongly with a caution here and there to be careful with removing too much material.

I could see using a hand file to reshape badly worn hammers that still have good felt underneath.  Using a dremel seems to be just a time saving way to get the same results.

What exactly is the difference in feel and tone from fresh or reshaped hammers?  Or rather, what effect does a grooved hammer have on the way a piano plays and sounds?

Also, regarding puffing up the hammers with alcohol, the manual recommends it for removing "click" from the strike.  In some cases I could see that being desirable, though maybe not always?

As an example, I once replaced a set of hammer tips on a Rhodes I used to have because many were badly grooved.  The result was that the tone of the piano changed completely - it no longer had an aggressive attack but sounded much mellower, due to the softer rubber of the new tips.  Cool, but not what I was hoping for.  Much like I never change the strings on my basses unless they break, sometimes a factory-fresh setup loses the character an instrument has acquired from years of use.

I have three different Wurlitzers, and they all to some degree have worn/grooved hammer tips.  I am fine with the playability and sound of them as they are but I realize there could be some improvement to be gained here.

Vintage Vibe seems to advocate for reshaping with a dremel sander and then re-regulating.

In the 200/200A Service Manual, section 5D on the regulation procedure mentions reshaping hammers with a sandpaper file (similar to dremel, just done by hand), but also mentions "puffing" up the hammer crowns with a 75% methyl alcohol solution.

Has anyone tried this?  Haven't seen any info out there with regard to this technique.  I have dug through VV's youtube videos pretty extensively and never see them mention using alcohol on the hammers.

Just wondering because it seems less laborious than reshaping the felt and re-regulating the blow distance, let-off, etc. but I would love to hear others' thoughts before experimenting on my pianos.

Check out a previous post I put up regarding 200 output level:

http://ep-forum.com/smf/index.php?topic=6813.msg33942#msg33942

In the different versions of the 200 amp, there is some variation in the way the aux out is wired.

I also set the internal gain trimpot to different levels depending on how aggressive I want the tone to be.  I run it at about 90% for loud rock, and back it off a little for a sweeter sound for pop etc.

Awesome, good find!  Maybe this could be a new sticky?

I think the "b" designation doesn't necessarily mean solid state. The 140, no "b", is solid state.

Vintage Vibe also has youtube videos up about a 145b yet that model is also tube like the 145.

Steve I based my statement about the 720/720b based on reading the 140/145/720 service manual, pages 4-6.  I have not owned or closely inspected any 720 model so I cannot claim personal experience on the matter.

I guess it is possible that there are discrepancies between the manual copy and what the factory actually physically produced.

I was also saying the 120 and 700 are harder to work on because in my experience the action assemblies are difficult to remove and replace (especially the damper arms) and the reeds and reed screws are oriented so as to add a layer of difficulty to the tuning process.  Those are the obvious issues anyway.

I would agree the 206/206a or 214 models are worth looking into.

Also in that youtube vid I'd say he's playing a 140 or 145.  During the keyboard solo at 2:00 you can see there are two knobs on the bass cheekblock.  I think there would only be one knob on a 120 unless it had been modified.

It is a different/classic sound, I agree.  Partially it's the 12 inch speaker in a big cabinet, but there are other aspects that likely contribute (different style reeds, different action, tube amp etc).  I also notice, at least in my particular 700, that the lowest octave has a lot of oomph (again most likely the big cabinet).

I wouldn't dissuade anyone from diving into an overhaul of one of these, but it is more laborious than working on a later model.

One last thing to keep in mind is that no one is currently making new reeds for these older pianos.  They are different from the newly manufactured 200-style reeds that VV is selling, so you have to find NOS or salvaged reeds, which are destined only to become more and more scarce.

The spinet models were the 700, 720, and 720b.  The 700 is essentially a model 120, the 720 is based on the 145, and the 720b is based on the 140b.   The 140b/720b were all solid state - no tubes.

I have the impression that most enthusiasts think the 720/720b is the more desirable of the two styles.  The action is generally better, and tuning and other repair work are considerably easier than with a 700.  The 720 also features vibrato which is absent on a 700.

I have a 700, a 140b, and a 200 - they all sound and feel different.  I would venture to say my 700 is almost radically different from the 200 in sound and feel (within the Wurlitzer spectrum anyway).

Whoever is looking to purchase this piano should be aware that old Wurlitzers almost always need a good amount of repair work and setup to get them in top form unless they have been getting regular attention.  They also can be costly to maintain unless you are capable of doing your own repairs and setup.

I don't mean to be discouraging though - on the contrary, there is a wealth of information out there for anyone who is interested in learning and developing a new skill.

The service manuals and schematics are available for free at Vintage Vibe's website.

https://www.vintagevibe.com/t-tech-manuals.aspx

They use a pretty basic tube amp power supply.  If you're familiar with those and know how to safely work around high voltages then it shouldn't be hard to repair.

Is the problem that your piano is not powering up?  If it is blowing fuses there is a short somewhere which would indicate either bad wiring or a failed component.  If it is not powering up (no pilot lamp, no sound and no glow in the tubes) but the fuse is intact then I would check the AC mains wiring.

If the filter caps are original they almost certainly need to be replaced.  If any of them are damaged (bloated, leaky, corroded, etc) then they are definitely part of the problem.

Also bad tubes can cause shorts and blow fuses.

If there is no visually obvious culprit, you have to systematically check the circuit starting at the power cable/AC mains, working your way forward to the fuse, line switch and associated wiring harness, power transformer, rectifier, filter capacitors, etc.

Bottom line, be exceptionally cautious while working on a tube amp - if you are not confident in your knowledge and ability to work safely, get a qualified technician to do the repairs.

If you have no luck finding a new cord, I could be convinced to send you mine - I am planning on converting mine to a 3-prong IEC anyway and wouldn't need the old one except to keep in my parts bin.

The cord that came with my 140B is not original but fits perfectly.  It's not round, even though the socket on the amp chassis is.  It's rectangular, and labeled Sony so I am guessing it's from a piece of stereo equipment or something like that.

So if you're looking for a new cord, don't assume it has to be round, just look for something with the correct receptacle type that is small enough to fit in the amp socket.  If you find a cord that will work but the plug is a little big, you might be able to carefully trim the rubber molding a bit to help fit it up.

If you have a 200 (non-A), the aux out taps into the signal at the volume pot wiper lead.  There are a couple resistors there which set the output level (and maybe a small cap, too - the arrangement varied with different schematic revisions).

If you have low output on a 200 you can try adding another resistor in parallel with the one between points 6 & 7 on the schematic (usually either a 100k or a 6.8k depending on the revision number).  You can play around with different resistor values til you find something you like.

Mine has the 5mfd/100k/15k arrangement of the early revision.  I tried the no cap/6.8k/2.2k setup but didn't like it, so I went back the original spec and also added a 15k resistor across the 100k.  That got me where I wanted to be in terms of the aux out level, it seems to be on par with the average guitar output at this point.

Also on a 200 there is a small trimpot on the amp board which controls the preamp gain.  If someone has set it low it will cut the output of the amp proportionally.  You can try playing with that as well.  Too high a setting may lead to distortion or even feedback.  For loud rock I like to run mine a little hot but not all the way up, and I back it off a little more for mellower gigs.

Low output may also be an indication of some other problem with the amp but if it sounds healthy in all other respects, the best and easiest places to start are what I mentioned above.

FYI I usually have my 200 running through a Fender 75 that is loaded with a JBL K130.

Just saw this come up today:

http://www.ebay.com/itm/WURLITZER-ELECTRIC-VINTAGE-PIANO-KEYBOARD-MODEL-110-SUSTAIN-PEDAL-/190590494102

With the fall cover, music rack, sustain pedal (with instructions!), service manual.  Not sure if it has legs/power cord.  Local pickup only.  Anyone live out that way?  Wonder what it will go for.

I bought one from Island Cases on a well-known online auction site.  (http://www.ebay.com/itm/ATA-GLIDER-Case-RECESSED-WURLITZER-ELECTRIC-PIANO-/230670527845).

Used to be 150, but 180 isn't too bad if your piano is worth $1000 or more. 

Nice thing about it is the lower half is just a shallow tray, so if you don't care about setting up a sustain pedal (or don't have one), you can just set the road case up on a keyboard stand, remove the lid, and you're ready to go!

The piano sits on some foam pads and I keep a right angle cord in the aux out.  Have gigged and toured the crap out of this case, it is pretty sturdy and light.  Not flight-worthy, but it is doing the job just fine.

Also, I ditched the cheap wheels and webbing, I think rolling the thing on pavement is asking for vibration and shock-induced trouble inside the piano.  I added a couple of inexpensive amp-style strap handles to one of the long sides and it works great.

I have another question about 120/700 pianos.  Is it possible to hook up an amp from a 200 or 200A to the 120 pickup, and the other way around (plug 200 into the 120 amp)?

I have the amp with my 700, it works but needs a recap pretty badly, but I'm just curious.  Wondering what my 200 would sound like through the tube amp and big speaker/cabinet, and what the 700 would sound like through the solid state amp, with vibrato, and out to a nice guitar amp.

I suppose it just depends on pickup supply voltage and input impedance being the same in both models, but has anyone ever tried it?  Don't wanna wreck any of my stuff just for the sake of curiosity.

Thought I would share a mod I made to my 200 after overhauling the amp.

R32 is the main resistor which sets the vibrato rate.  Normally the value is selected at the factory to set the rate around 5.75Hz.  Mine had an 18k resistor, at the low end of the range on the schematic.

I played around with some parts and found that for my amp, a 15k 1/2w resistor in series with a 25k linear taper pot worked pretty well as a rate control.  The adjustment range is not huge but definitely usable and musical.

One has to be careful selecting component values as the oscillator will stop working if there is too little or too much resistance at R32.

There was a little bit of thump at the slow end of the rate knob, which pretty much disappeared when I got around to replacing the three .12uF caps with new ones.  Tweaking the value of C39 a little might help solve this problem too.

After I was satisfied with my component arrangement, I soldered in two leads to where R32 was on the board, custom-made a bracket for the rate pot, and installed a 3-knob faceplate from Ken Rich Sounds, normally sold with their custom 200 amp and vibrato unit.  They were able to sell me the faceplate for the same price as a 2-knob version.  I had an extra 200-style knob laying around, so it looks very seamless.  Will try to put up photos of this at some point.

Also, R32 could also be replaced with a trimmer or internal pot, if you don't want to mod your case but still want to be able to control the vibrato rate, say for a specific recording, etc.

The whole mod cost less than $50, and most of that was for the new faceplate.  The speed range available is not as impressive as the Warneck VariVib or Vintage Vibe's new custom amp, but for the low cost and ease of installation, I think it is pretty good.

I fully rebuilt my 200 amp using Vintage Vibe's kit, some extra pieces from them, and a few trips to my local electronics store (which happens to be Brill/Master, a huge electronics distributor that actually has counter service in my neighborhood)

Anyway, I had trouble finding the three .12uF 100v mylar vibrato caps (they weren't included in my VV amp kit).  I tried some .1uF caps but the vibrato oscillator is apparently very sensitive to component values, and it stopped working.

Probably could have gotten it going again with some different resistor values, but I found the following on ebay: http://www.ebay.com/itm/370378550191

Cheaper shipping than ordering from Mouser, and they look exactly like the old caps.  They are perfect replacements, in case anyone is looking for those.  I bought a few extra just to have around for future repair work.

[Let me be clear, I don't want to imply that I think EP parts suppliers are gouging customers]

Wurlitzer reeds can NOT be welded together, or repaired in any way. I seriously doubt that a hacksaw blade would work as a reed. They are too flexible, and I doubt the tone would be the same even if you could add the solder and tune it. If you are in a REAL pinch, you can use a reed from a 200 series or a 140 series to HOLD YOU OVER. It is not that they dont work in the earlier models, it is that they sound different. Too many people incorrectly state that they do not work in other models, which is not true at all.

My hunch is you are correct, steveo, but maybe it's worth trying at some point?  Also, the reeds are just steel.  Maybe a very certain kind of steel that is custom alloyed and heat-treated for the reed manufacturer, but definitely nothing from outer space.

Being a machinist/maker, I see a lot of things in the world that are expensive and highly specialized, but really are just carefully selected and prepared from commonly available material.  One thing like that I am wondering about is 120 series damper felts.  Are they really a special felt, or is it just $2 worth of material from McMaster-Carr (or similar), cut to the right size?

Let me be clear, I don't want to imply that I think EP parts suppliers are gouging customers - it costs a lot of money to run a business, manage inventory, develop new products, produce parts from raw materials etc.  Not every person on the street has the knowledge, skill, resources or time to do it all themselves.  I think the prices the suppliers charge are pretty reasonable considering the service they are providing.

Anyway, I didn't intend for this post to venture into this territory, mostly I am wondering about the age of my 700, and if anyone has seen one with the features I mentioned.  I think this talk of 120 series reeds could be moved into a different topic, as it will inevitably become a service issue as replacement parts start to dry up.

Thanks for the encouragement!  I may already be on the slippery slope of keyboard repair.  I started with overhauling two Rhodes MK I stage pianos, then got my 200 about 18 months ago (which came to me as basically a box of parts - good motivation to learn how to work on those).

Earlier this year I traded a working Rhodes for a non-working Vox Jaguar.  It had a bad power supply and needed a bunch of cleaning, and a few transistors replaced.  I just gigged with it for the first time this past weekend!  I guess part of my interest in these old keyboards reviving the life and soul in them, and making them useful for musicians and audiences again.

I certainly lurk on ebay/CL for Wurly stuff - anything that's a good deal gets on my radar.  Since I now have my 200 in great shape and the 700 on the way, I am mostly looking for a 140 or 145 now, and smaller spare parts on the cheap.

About reeds, I have thought about trying to repair broken reeds as a last resort.  I don't know what alloy the steel is but it might be possible to very carefully weld them back together.  If it's a hardened steel, which I'm thinking it is, the welding will anneal the metal and it will need to be rehardened.

I could also see hacksaw or bandsaw blades being a possible source of material.  My shop certainly tosses out a lot of used blades.  If they were the right thickness it could be done, but who knows what the tone would be like?

So it's maybe a lot of effort to do these workarounds if replacements continue to be available, but I don't think anyone is making 120-series reeds anymore.  I think Vintage Vibe probably put a lot of time and money into perfecting the new 200-series reeds that they are now offering, but I don't know if the demand is there for them or someone else to do the same for the older models.  It may be that some experimenting will be required going into the future with these very old pianos.

Hello, my first post!  I'm an EP/vintage keyboard enthusiast and tinkerer.  I have a day job as a machinist and technician for a science museum.

Recently I did some repair work on a 200 for a friend who is a touring artist, and he gave me a 700 he wasn't using in return. I'm somewhat familiar with the 120, but have never owned one.  I know it's not the most desirable model, but I hope to learn some things from working on it so I can build my skill set.

From what I can tell, this 700 could be a very early example.  The speaker is a Jensen P12R from late 1957.  The transformer codes are from Sept/Oct 1958 or so.  Several things about this piano differ from what I have seen in photos of other 700 models.

In particular, the volume knob is on the name rail, and the pilot lamp jewel and headphone jack are on the lower front panel below the bass end of the keyboard.  I think these are typically located on the bass side cheek block, correct?

I also noticed in the service manual, it mentions that the procedure for removing the top is slightly different in very early production examples - on my 700 the screws are underneath, behind the back panel.  The top is secured in front by means of angled cleats.

Supposedly these were made as early as 1959 (sometimes I see '58 mentioned), but has anyone ever encountered one of these with the features I mentioned above?  The finish on this piano is not in very good shape, and all of the damper felts are gone (they were replaced long ago by open-cell foam weatherstripping, which has fully disintegrated).  So it is not going to be a collector/museum piece, but I am still curious about the manufacture date.

Also, if anyone has a spare #19 Eb reed for the 120/700, I would love to buy one from you.  Vintage Vibe is currently out of stock on those.  I could also make do with a #18 D and just tune it sharp.