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Messages - sopranojam85

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1
Whilst I haven't had a look around for those values I find that if a pot has broken like this I usually open it up and remove the carbon track board and replace it with another of a similar value and size.

Last one I did was for a Wurlitzer 200a, the volume / power switch is a pain to get if you're not in the US.

The resistance track was completely destroyed so instead of purchasing a new one for $25 and then the P&P of $34 I bought a new CTS 10k pot and used that as a donor to put into the original Wurlitzer pot. Total cost £2.50.

This was what I tried doing initially, as I recall. But, the tracks were a different size. The diameter of the pot shaft does NOT always equal the inner diameter of the carbon track, so it is impossible to know by just studying pot data sheets for new pots. You just have to open up a few scrap pots until you find the one that fits.

2
One more thing to note...

A few months after I made this repair, this same EP suffered some water damage from a leaky ceiling. The moisture caused some of my epoxy joints to fail, and the washers I had installed to fit the new pots no longer were attached firmly. I had to re-do some of this work.

I was able to save the piano though after a lot of work. And here it is after it was all said and done.

3
Somebody has private-messaged me asking for more detail about what I did. I felt it was proper to place the information here. Sorry if some of this is redundant, but here goes...

The original two pots were 25k, and 100k reverse log pots. They were large, and had a long threaded neck. Finding pots of this value and size was impossible. At every turn, either the shaft length was incorrect, or the pot value was improper. The only option (aside from buying a spare Rhodes preamp altogether) was to buy correct-valued pots, but of a smaller size.

The original pots served as a structural support, as well. The new pots were not long or wide enough to still serve as structural supports, so a new structural support was created off to the side of the pot hole by epoxying a threaded neck (taken off of the original pots, I believe,) to the back side of the name rail, drilling a hole into the preamp chassis, and mounting the preamp to the name rail. (Photo attached.) See in the photo two holes marked in pencil. One on the left is the location of the hole I drilled for just the old pot neck, as a structural support. The one on the right is the hole to be drilled for the pot itself.

Since the shaft of the new pots was also smaller, and to prevent the leads shorting to the chassis, three measures were taken: 1) Holes of chassis were made larger, with room routed out below holes for pots terminals. 2) Insulation pieces glued to edges adjacent to leads. 3) electrical tape pieces placed on back of name rail where pot leads were present, just to prevent any shorts.

The name rail holes were not made any larger, but they were too large for the pots. So, I CA glued two medium-sized washers to the front of the holes on the name rail.

Finally since the lugs of the pots did not reach the PCB, extensions were crafted with tinned wire and soldered in to place.

I am sorry but I do not know what exact model pot I bought, but it is made by Alpha. I made sure they were 25k reverse audio, and 100k reverse audio.

4
Parts, Service, Maintenance & Repairs / Re: Shop Tips and Tricks
« on: April 26, 2016, 09:30:45 AM »
I've always wondered what was the translucent pasty stuff on tone bar screws. Bee's wax? That makes sense. Never seen mention of that in the Rhodes service manual, unless I'm just completely missing it.

Thank you - this was a fantastic thread. Lots of things I should now add to my toolbox.

5
Parts, Service, Maintenance & Repairs / Re: Gap under the name rail
« on: April 21, 2016, 09:49:31 PM »
Very nicely done.

6
Parts, Service, Maintenance & Repairs / Re: Gap under the name rail
« on: April 21, 2016, 10:59:12 AM »
@pianotuner steveo - Sorry again for the blunder in vocabulary.

@OP - if you've installed the pedestal bumps correctly, you've already had to remove the piano from the case. Upon doing so, you can see the screw that fastens each of the plastic cheek blocks to the wood beneath them. This screw, and the one on top should be the only ones keeping the plastic fastened to the wood underneath.

The wood underneath the plastic cheek blocks should be a separate piece from the rest of the frame. I have only had to remove this wood one time, on a water-damaged Rhodes Suitcase. On that particular piano, that piece of wood was stapled on to the key frame. Maybe yours is too, or nail-gunned in by the factory, so it is hopefully not much of a challenge to pry it off. From there, you can attempt to sand them down, test the fit, etc. Once the fit is good, glue the wood back on to the frame, reinstall the plastic cheek blocks, etc. Good luck!

7
Parts, Service, Maintenance & Repairs / Re: Gap under the name rail
« on: April 20, 2016, 08:16:38 PM »
If the piano plays well, keys leveled, key dip proper... Don't raise the balance rail felts. I'd suggest working on the cheek blocks as previously suggested. Maybe trim the wood beneath them?

If there is too much key dip or the keys touch the front rail felt, get thicker balance rail felts.

8
I mean the shape of the screw-hole end of the reed.. yes. the 200 series reeds have a sort of corner cut out. Older series piano reeds do not, and are symmetrical there.

9
You're right. Forgive my numerical mistake. Whatever they were from, the "incorrect" reeds were perfectly symmetrical.

They may have been from the 120, 140, or 700 series pianos.

10
I had approximately the same problem with some reeds, and discovered it was due to the reeds being incorrect. They were most likely reeds from a 170 series piano which were cut to forcefully work with a 206a. Closely compare the shape of the reeds in question to the others. 200 series piano reeds are not perfectly symmetrical. Close, but not.

11
I just installed the Warneck Research EP200A, and I gotta say, it's the best sound I've ever experienced from a Wurlitzer. Minimal noise, huge amounts of headroom, and no distortion to speak of.

Speaking of distortion, I don't particularly like the sound of saturated transistors that happens so readily with the original amp. It's a most unpleasant form of distortion. In my humble opinion, the amount of time and parts needed to rebuild or refresh the original Wurlitzer 200A series amps is much better spent towards an EP200A. I'll certainly be plugging these amps from here on out.

12
Nope, but I did disconnect R26 (the resistor attached to it.) I presume your question was leading me to know whether or not the "Mike" input circuit was out of the picture, and it is. R20, R23 and R26 are disconnected at the moment. It didn't make a difference in the noise level.

13
I replaced the IC today with a brand new one from Mouser as I mentioned above. It made absolutely no difference, unfortunately. I thought it rather strange that hooking up a dedicated 15V bench power supply was quiet. Hmm. I don't know what else to attribute THAT to except that maybe my bench-top power supply is noisier than I think, and that this noise "drowned out" the popping/crackling sounds during my test.

Oh well. The worst part was -- I had very intermittent 60 Hz hum. It would come and go. Very VERY loud hum. It almost sounded like a microphonic tube. I'm used to hearing closer to 120 Hz hum (rectified AC) but this hum sounded like a pure 60 Hz sine wave. It was alarming.. I spent a good while trying to track this down without much luck.

All I can say is that as of right now, I have removed the new IC and put the old IC back in. All is well. (As it was before.) The crackle, I can only attribute to old and tired transistors at this point.

The owner of this Wurlitzer is going to get an early Christmas present though. I'm ordering a WR EP200A because I'm fed up with this amp.  ;D

14
For some closure on my own thread, a fellow tech shared this nugget of info: Mouser # 595-UA723CN

15
Parts, Service, Maintenance & Repairs / Re: Wurlitzer 200a problem
« on: November 24, 2015, 05:11:09 PM »
You've described what a "lifted trace" is. Depending on how much of the trace is damaged, you may or may not be able to cut the broken segment, sand a bit of healthy trace to expose the copper, and then run a small trail of solder from there to the component pad.

If it's more than a couple millimeters worth of trace that is broken off, you'll need to connect a small jumper wire from point A to point B.

Back to your original question, I've never experienced a blown fuse on a 200a amp strictly from a reed touching the pickup. Makes a nasty sound, for-sure, but I do not know if that would blow a fuse. A hard short might, and if you play hard where a bunch of signal passes though, I imagine this could blow a fuse. Use a multimeter continuity test between a reed and the pickup to be sure there's no short before you power it on again. When I tune a Wurlitzer I always leave the amp off while tuning for this reason. Also, each time I power the amp off, I briefly short the pickup bar to a reed to discharge the caps. Otherwise I get a nagging (but not harmful) little "zap".

16
Hi everyone,

I'm working on a Wurlitzer 206A with a subtle, but somewhat nagging issue. There are audio artifacts (high frequency) that sound a bit like a crackle, or static. At other times, the sound is periodic, about 3 or 4 "clicks" per second. I know that the sound isn't coming from the reed bar. The reed bar is completely disconnected from the amp board. I have traced the source of the signal to the 15V rail of the power supply. This is the only rail of power that I can pick up this sound occurring.

The board has had all electrolytic caps replaced, and this made no change in the issue. All resistors are well within tolerance.

I can see that the 15V supply is coming from a Motorola 142349 IC. Since I didn't have one of these handy, I disconnected the 15V leg of R28 and R23, and connected these to a separate 15V DC power supply. Sound disappeared.

The 22.5V and -22.5V rails are looking very good. I've replaced the 4 power supply diodes, and this smoothed out what little AC ripple it had by even less. There appears to be only 2 or 3 MV of AC ripple on these rails, and no other anomalies.

So this leads me to wonder if I can replace that voltage regulator. What's an equivalent replacement for the chip? It's got a big M on it (I assume a Motorola logo), and has part number 142349 silk screened on it. So far the most likely candidate is this one, but I'm not sure if it's all correct or not. http://www.weisd.com/test/GenericParts_WEISD_view.php?editid1=142349

17
You could purchase a suitcase preamp, and then get a power supply for it, to give you the sweet suitcase vibrato you may be after. Vintage Vibe sells cheek block power supplies.

But it's a hefty price to pay. Most vintage suitcase pres will require some level of rebuilding (recap, etc.) By the time you buy the preamp, buy a power supply for it, you may decide to just set it up as a stage piano passively, and find a stomp box or effects box to supply your desired tremolo.

18

I've heard that 200 reeds are thinner than 200A reeds. Any truth to that? Maybe that's the thickness taper I'm measuring?

I don't know. But, we do know that people who sell replacement reeds make them so that they work with both 200 and 200A series pianos. If 200 reeds were originally thinner, they'd have to have slightly different cut lengths, or a different volume of solder on the ends of them. I'd think that a thicker reed would hold up better to abuse than a thin one.

Is that spring steel coated with anything? Unless it's stainless steel, as I understand it, it will corrode over time and must have some kind of coating on it. Original reeds have some sort of coating, but I am not sure exactly what substance, or process is used to coat them.

19
It sounds like Retro Linear will have their mid range reed blanks back in stock soon! The RL reeds are the only ones I have tested that sound correct and are robust enough for use within a musical instrument. They are the only replacement reed I have ever played that meets these two critical points.

I just got 3 reeds from Retro Linear, and am about to install them into two pianos waiting for them. I'm glad to hear that you've had good experiences with their reeds.

I'm also glad to see that the mystery of what the original were made of is (somewhat) revealed. geoff004, I admire your DIY spirit and ambition here. Hope you take all the criticism with a grain of salt and don't let it discourage you. Which manual did you find the info on "Sandvik spring steel"? Any chance this manual is around online, or can it be scanned and posted somewhere electronically for us to see?

20
Hello,

I'm about to get cracking on a Rhodes Janus I 50W Amp. This is the vertical free-standing ones that Rhodes intended you to buy either one or two of them together. Anyway, there's only one, and it's developed a fairly horrendous crackling sound.

I'm not 1,000% certain, but am mostly certain that this is the proper schematic for this little beastie: http://www.fenderrhodes.com/org/ch11/fig11-3.jpg

It's been interesting trying to differentiate between the suitcase built-in amps, and the stand-alone amps. If this is not the right schematic, I'd appreciate a gentle shove in the right direction.

This is coming back to the shop for a re-work. The original problem was a crackle, and I noticed that the Power transformer was dangling off the chassis by one nut. The hardware mounting it was all stripped out. I replaced all the hardware, and the crackle went away. While the amp was out, I put a dummy load on it, powered it on, and measured 38 V on the 30 V rail. So that's an area of concern. Something is probably not drawing enough current, or the voltage regulators are not doing their job, or both.

Does anyone know what the expected AC voltage is on the power transformer secondary windings for these things? (Power on, and secondary windings disconnected, freely measured?) I have a notoriously bad time with power transformers failing, and before I start chasing IC problems, I'd like to make sure the power transformer is doing its job.

Also a recap is in order, and replacing any off-spec resistors... Any advice is much appreciated. I'm more a tube guy.. this solid state stuff is easier to work on, but harder for me to understand.

21
Thank you. I was sure the answer was easy to find.

22
I hope I'm not the first person to ask this question. I also hope it's not a dumb question.

Why do Rhodes pianos have front rail punchings to being with, if they are not supposed to make contact with it?

23
Parts, Service, Maintenance & Repairs / Re: Some reeds too dang quiet
« on: August 04, 2015, 01:32:24 PM »
Hey so, guess the database problems "ate" my last reply on this thread.

The problem was that these were the wrong reeds. They appeared to be 100 series reeds, as they were perfectly symmetrical. They looked just slightly different from the rest of the reed bases. Mystery is solved.

24
Parts, Service, Maintenance & Repairs / Re: Some reeds too dang quiet
« on: July 28, 2015, 10:35:59 AM »
All good questions!

I do not see how changing the reeds will make any difference at all, unless you somehow damaged them, or they are the incorrect reeds.

The piano was like this when it got to me, and I'm confident the low volume was not my doing. Not sure if they're incorrect reeds or not, and not sure if I'll ever know.

You are correct that reeds go flat, then break when bad.  You are not supposed to sand, file or steel wool any part of a Wurlitzer reed other than the solder tip. There is a rust resistant coating that shouldn't be removed. Cleaning a reed should be done with light oil, not an abrasive.

Well most of the debris was where it met the reed bar. The manual does state to use emory paper on the reed to address that issue. Maybe I shouldn't have steel-wooled the middle of the reed, is that what you mean? I couldn't find any reference to using oil in the service manual, unless this is something that is tribal knowledge, which I have equal respect for.

I just re-read your original post. I'm not picking on you, but for future reference, you should never file a Wurlitzer hammer tip either. They are just too small for this treatment that is normally done on acoustic piano hammers or old Rhodes teardrop hammers.

The service manual does specifically call out to do this if necessary, so that is one reason that I decided to try it. I actually did a very gentle filing of several hammers which needed it, because some notes had the felt heavily indented at the striking point. I'm well aware of how thin the felt is, so I did not file much at all. I filed from side towards the striking point, and not directly on the striking point. Obviously filing had no effect on this specific issue, though.

Did someone file the pickup around those reeds? (increasing the space around the reed tip and sides) That will make them quieter, and is also a no no.

No, the pickup is tight, and I checked the gap with my feeler gauge, it's around .005 on both sides, pretty normal.

Is it possible that someone added a chemical to those two hammers causing the felt to be softer?

I'm sure anything is possible at this point. When I had the reed bars off and was inspecting the hammers, I cannot feel any discernible difference in hammer hardness from treble to bass. If anything, the extreme treble hammers feel a bit harder, since their felt is thinner there.

Are you positive they are not letting off too early on those two notes?

I'm sure. I experimented with increasing and decreasing let-off, neither of which had any huge effect on the volume of the reed, so I left it at 1/8" let-off.

I did swap #37 with #38, and the issue followed the reed, not the hammer. Reed #38, when on hammer #37, played loud and clear.

25
Parts, Service, Maintenance & Repairs / Some reeds too dang quiet
« on: July 27, 2015, 11:22:51 AM »
Hello folks,

I'm working on a Wurlitzer 206A which has notes #36 and #37 that are entirely too quiet. I've done all I can think of to fix the issue, including:
-- Sanding all sides of the reed with emory paper, then 0000 steel wool (These reeds are shiny enough to shave with now.)
-- Sanding the harp surface contact point of the reed.
-- Removing all solder and starting over. (It now has a perfectly-shaped flattened pyramid of solder that is fit for a diorama.)
-- Setting proper let-off and check-off
-- Adjusting hammer striking point and gently filing hammer tip to be a bit more pointed.

No luck.

I've even tried swapping reed #37 with reed #38 and the issue follows the reed - not the key. (Admittedly, I probably should have done THAT before messing with the hammers, but what's done is done.)

It's seeming clear to me that I need new reeds. But I've read (here, and elsewhere) that reeds don't go quiet. They go flat and brittle, and then they break. Yet, the Wurlitzer 200 series service manual states "Any foreign material on the head of the reed will dampen the oscillation. If this does not cure the ring time, the reed should be replaced."

Am I missing something? Meanwhile, both Vintage Vibe and Retro Linear seem to be out of stock of their reeds, and even everyone's favorite auction site has some reeds, but not these ones. I'm kind of high and dry on reed supply unless someone knows of another source.

Thanks for any help!

26
I have finally finished this repair. Some of you may hate me for doing modifications to the preamp chassis, but everything I did was done to preserve the outer appearance of the piano, and to preserve its electronic functionality.

In a perfect world I would have been able to find the pots I needed, but it was impossible to find reverse log pots of these values, and of this size. So, I ended up buying small-ish pots of the proper values, but which were smaller bodied. They were 16mm diameter, with a 6mm shaft that was knurled (so it fit the original knobs just fine.)

(Another option here would have been to buy a separate Rhodes or vintage preamp module, altogether, but that was cost prohibitive.)

Since the new pots were way smaller, they could not serve the purpose of being a structural support for the preamp chassis. I had to construct a new support for that side of the preamp chassis. What I did was disassemble one of the old pots and remove just the threaded neck of the shaft. I shaved the bottom surface of it with a Dremmel, and epoxy'd it to the back of the name rail.

I then cut a hole in the preamp chassis at the exact place where this threaded neck was to protrude through that hole, and screw on with a nut. This worked really well, and had no visible impact on the front of the name rail.

In the photo, the brass threaded segment is this new support I'm speaking of poking through the inside of the preamp chassis.

Next, I had to attach the new pots. The shaft was smaller, so the holes that were there were too large. I also needed room for the new pot terminals, to make sure they didn't short against anything. I used a stepped drill bit and Dremmel to cut out a hole sort of shaped like a large key hole to accommodate the new pots. I CA glued rubber insulation to the metal chassis edge that was close to the pot terminals.

To make the fit of the pot shaft more secure, I CA glued a couple of medium sized washers to the front of the name rail. This was not my first choice, but it was the most sound choice structurally, and the washers are concealed by the pot knobs when the knobs are on.

Finally, I had to construct small extensions for the pot lugs to reach the PCB. I had some good quality tinned wire handy which I used to shape L-shaped extensions and solder them in. The photo shows these extensions. These extensions are a LITTLE bit flexible, so if the piano ever gets roughed around or dropped again, it will hopefully not break anything major, as there's some flex to these wires.

Everything is reassembled, and tested 100%. I'm very happy with this repair, and I am confident that it will never need to be repeated. But, heaven forbid, if it does need to be serviced, it is much easier to remove or replace these pots now that the necessary mods have been made.

While I was at it, I replaced the damper rail bushings, the RCA jack, and realigned the harp to adjust the striking point.

27
They're both this same physical size, but one is 25k, the other 100k. My ruler is in inches, but converting to mm, you can get the idea of the measurements.

I found a metric ruler and here's the measurements:

23mm pot diameter
6mm shaft diameter
25mm total shaft length
9mm knurled length
16mm threaded length
Terminals 7mm apart

Like I was saying earlier, the threaded length is so long because it goes through both the preamp chassis hole, and the name board hole, each having its own mounting nut to fasten it. It's both a functional pot, and structural support for the preamp chassis.

28
Here's one of the two victims. When I desoldered the pot, it just fell right off, and the break was evident.

29
Having issues with attachments, so going to try one photo at a time. This photo is the name board, and preamp chassis behind it. Obviously the pots themselves are not installed, but you get the idea of their positioning and hole size.

30
Hello everyone! First post here, and I hope I am putting this in the correct location. I have a Rhodes Mark I Suitcase piano which suffered a fall on stage. Everything was fixable, except that the vibrato speed and depth pots were damaged - their lugs sheared in half right where the lugs meet the pot's body, making them completely trashed.

I'm looking for replacements, and am having a heck of a time finding ones of the same size.

These are 25k and 100k reverse pots. The body of the pot is 24mm in diameter, and it has a 6mm-diameter shaft. The total shaft length is 25mm, but the tricky thing is that the threaded portion of the shaft is about 16mm long.

I understand why the threaded portion of the shaft is so long; it is used to structurally support the preamp chassis behind the nameboard. The threaded portion must protrude through the preamp chassis, AND through the nameboard.

I managed to find a few pots with a 25mm shaft, but none which had a threaded length even close to 16mm. (8mm was as long as I could find.) Reverse pots are the most limiting factor here, I think. They just are not as plentiful as standard pots. I've lost track of the number of suppliers I have checked with. I remember for sure that I've checked with Mouser, Digikey, Newark, Vintage Vibe, a few eBay sellers, and also Alpha. Alpha can make this pot if I provide them specs, but a minimum order size of 1,000 is required...  :-\

I'd love to find an identical replacement without actually buying a junk preamp or Rhodes to do it. Any ideas?

If worse comes to worse, I will have to make a few mods to the preamp chassis (NOT the nameboard.. just the chassis behind it) to accommodate the body of a shorter-length-shaft pot, and come up with a way to support the chassis elsewhere.

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