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is your synth on top of the rhodes? maybe it is an electromagnetic interference and could be fixed with some shielding. not sure just a thought

That's right, if it's a Pro-Piano for a MK2 they used an aluminium foil sticker. This is due to the width of the MK2 faceplate.

The Pro-EQ and Pro-Piano MK1 are aluminium faceplates.

mines definitely a mark 1, on the harp a date was handwritten written in 1983, so seems like its a later dyno ( i just thought that the dyno guy who worked on it left his mark)

Stevie,

Using a different wall wart to power this circuit will not fix your Li-ion battery charging problem.

I assume that the circuit was designed for an AC-AC wall wart transformer, not the 15V DC supply you are using.  However, if your 15V DC supply is working, then keep it.

The 15V DC input will probably make the power-on indicator red LED run hot and bright, but as long as that LED is okay with 50mA and the resistor doesn't burn up from the 0.675 Watts (it is rated for only 0.500 Watts), AND that the input voltage is high enough that the 78M15CT regulator doesn't go into cut out, well, you are fine.*

If this were my Dyno, I would swap the current limiting resistor that feeds the power-on red indicator LED with a 1KΩ 1/2-watt resistor (the LED should light up just fine with 13.6mA).


* The input voltage to the 78M15CT regulator is supposed to be two volts higher than the output.  The spec sheet lists the "Dropout Voltage" as 2.0V.  But if the circuit isn't sputtering and shutting off, then the regulator is working fine. 


Sean

Thanks again sean, but whoa whoa whoa youve gone a bit over my head. I might have to have an electrical engineer buddy of mine take over, Im just a dentist...

first of all, there is no red power led. only the green one located in the cheek block near the ac/off/batt switch, so maybe the circuit diagram is for something else

if you wouldnt mind educating me (im getting very interested in all this) why would the Li-ion batteries be any different than NiCd or whatever?

But I feel like your solution doesnt achieve the goals of 1 - not having to take the batteries in and out frequently  and 2 - having the rhodes work without needing to be plugged in to turn on, only just charging it up by plugging it in temporarily and then having it last a while

also 3 - not having me mess this up by trying to futz with the circuit board. id rather leave it as is changing the dpdt switch was almost beyond my abilities

how do I get there? Should I get new batteries and a new power supply? what risk am i running if i just keep things the way they are now, which doesnt seem bad

Funnily enough I've been doing a fair bit of work around re-making Dyno Faceplates and the power circuit for a couple of restorations.

In the next few days I should have my new PCBs come in to replace the toasted one I had come in.

Will update the thread later on with some pictures.

it seems like the dyno faceplate on mine is a sticker overlaid ontop of the original rhodes faceplate, interestingly enough

I have been looking to upgrade my amp situation, my little fender sidekick 20 with a 10" gets good enough tone, but has a weird rattle on the low end that I cant figure out. My little hartke bass amp doesnt have the rattle, but sounds lifeless

A friend is offering me his peavey renown, its a huge beast, solid state, 120 watts, has a lot of eq control, including a shift knob which i guess scoops out certain frequencies. spring reverb built in sounds pretty good

Its alot of amp for my needs, I just want to play in my home, its known to be a very loud amp, but I wonder if at bedroom volumes (i like it kinda loud though) it would sound good and clean. I understand its not a very desirable guitar amp because its heavy as s**t, and super loud and clean. Loud and clean sounds like a good combo for the rhodes, no? Im not worried about space or hauling it too much.

what do you guys think? any experiences?

also any recommendations on settings for it? I usually just leave everything at 12:00 and like the sound

wow thanks for the great response! you really know your stuff

i bought these https://www.amazon.com/gp/product/B07RNNGHQQ/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1 lithium ion rechargeables

I didnt get a dedicated charger for these because I didnt want to have to take them out all the time and I thought that the whole point was this circuit charges the batteries. just plugging something in seems much easier to me

at this point, the situation seems to work fine. when I first installed the batteries, it didnt work. then when i plugged in the charger, the light flickered a tiny bit like you said, then the batteries charge up and hold it for quite some time. i think i've accidentally left it on overnight  unplugged and it was still working. 

I dont know alot about electronics but youre saying theyre not charging up to the full potential? do you think that having a lower voltage changes something? I dont know if i can tell a difference between this and when I use fresh non-rechargable 9volts, but maybe my ears are missing something.

what do you think? do i need to get a new powersupply, new batteries, what? I saw this http://www.caesound.net/dynomypianopowersupply.aspx but its a little steep

I am not worried so much about the light as I am just providing reliable power to this thing that wont give out in the middle of a set or something. the light not lighting just tipped me off that something might be wrong

decided to revive an old thread instead of starting a new one

I also have a dyno and didnt want to switch out 9v all the time, so I bought some rechargables and this https://www.amazon.com/gp/product/B07B3WNTCN/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1
it seems to work and the batteries seem to hold a charge when its not plugged in, but i was having one issue. The little green power LED i understand should be coming on if its charging but it doesnt? heres the schematic i've found
https://cdn.shopify.com/s/files/1/0666/2821/files/dyno_mod.pdf?14847120881916368966

I wonder whats going on. I also had to replace the dpdt switch so maybe that messed something up?

https://www.youtube.com/watch?v=KUL7K7RQ8HM

saw this a while ago and just thought to share. I was blown away by how cool he still is

now that I actually received the piece, I decided for now just to clean it up and leave it as is. interestingly some of the edges were really flaky and had some white oxidation. After cleaning that all off and brightening up/polishing the metal of the foot part it actually looks really great.

I really like the "natural relic" look on guitars, so why not on my piano parts. It fits with the esthetic of the rest of the piano as well as there is alot of pitting to the chrome hardware and such

ive never seen one, and the piano will never leave my music room. i guess im interested in it just to have the complete package. probably stupid  thanks for the tips

Im sure you would have an easier time just listing two of your legs on reverb or ebay, even individually, then buying reproductions of the back legs on vintage vibe or something like that

looking for the vinyl leg bag. around I'm thinking around $25 based on recent sold listings on reverb. you know yours is laying around somewhere and you dontt ever use it

If you have any other ideas or suggestions, let me know, its been a great journey so far but I know its not over

Spray painting the tone bars:

The tone bars were super rusty, and I had to replace the grommets anyway, so i took the tone generators all off and cleaned them with an ultrasonic cleaner we have at school, then hit them with the scotchbrite. that removed the all rust and white fuzz, but left them looking all mottled and I felt like they would just get rusty again faster. I know alot of people re-plate them, but I just cant afford that right now. What I lack in money, I make up for in elbow grease, which this took A LOT of. All the screws were rusty too, so I chucked each one up in my drill and polished the heads on a scotchbrite, none of them were bent so I didnt want to replace them. Interestingly enough they were threaded all the way through.

I taped off the tines and toneblock and spraypainted them with primer and gold rustoleum for looks and protection. I read some posts on here saying that it shouldnt affect the sound and I painted a very light coat. I did not notice any negative change in tone or sustain. replacing the grommets and doing the voicing was a big improvement, so maybe too many variables to tell. I did the harp frame as well and it looks amazing in there now. Makes me want to leave off the harp cover.

I think they look great and wont rust now. Let me know what you think?

Hey guys, just wanted to share my journey at this point

Loved the sound and history, always chased it, dreamed about it, had to have it. It started when a friend gave me a yamaha cp-20, an analog synth with an interesting sound, more like a wurlitzer than anything, but didn't quite do it. Then I got the Rhodes mk80, a huge improvement, but still didnt scratch the itch.

Checked craigslist religiously for years, but nothing ever seemed to match my poor dental student budget. I always figured I would just have to wait until I graduated and started making money. Then I saw her, only $500, missing legs and pedal, but it was a chance to have the real thing. She has a dyno, which is really cool. I lived in San Francisco at the time, so it was cool that the mod was done pretty close to where I live. On the harp was written a date in '83 so i assume that's when it was done. Harp date 1375

Luckily, everything else was there and surprisingly functional. To be honest I got lucky as I didn't know what to look for, it could have been a lot worse at that price. Seems like the rubber hammer tips are pretty good and the felts are also not bad.

So far I've given her a good cleaning, painted the tone bars and harp frame gold (see next post), made my own pedal and rod, and changed the grommets (I used the avion ones and am happy with the results, see the before/after) I voiced and tuned it somewhat, but I want to take her to a good tech (if anyone has recommendations for the best in Los Angeles, let me know). I also replaced two dead pickups and a faulty switch on the dyno

I made the pedal out of some 2x4 scrap and an old piano pedal I bought on etsy for $10, the rod was a 3/4" dowel that I put an old drum part on to make it adjustable and had a long 1/4" screw sticking out. it worked surprisingly well

It came with some old table folding legs screwed onto the bottom, I've since sourced original legs, crossbars, and an original rogers rod for $190 (thanks Chris!). An original pedal is on the way i got for $60!

Tolex on the back is all messed up, its up against the wall and you cant see but I plan to fix that soon enough.

whatever year your Rhodes was made is the best year.
In my opinion, early '75

interesting. I like it to be honest its got an understated look

great tips thanks! I guess my biggest worry is that there are areas of the finish where the aluminum has been exposed probably for a while, and when the paint is stripped, the result will look mottled unless its all made uniform through sanding or polishing somehow

wondering about the finish on an original rogers sustain pedal rod. In photos I've only ever seen chrome shiny looking ones, but I just got one with more of a pebbly/satiny finish. Says USA rogers on the wingnut and everything

Whats goin on here? This has gotta be deeeep in the rhodes knowledge archives, because search turns up nothing

I am trying to do the opposite. Im getting a black pedal that is very worn out, but want it to be silver in color ( I prefer the look, and its appropriate for the year of piano)

What should I do to achieve the original silver look? I have some spray on stripper in the garage I think
Im guessing take it all apart, spray the stripper on the pedal, scrape off the thick paint (hopefully its that easy) and then sand paper up the grits? but how polished?

anything Im missing?

I have a philosophical question for the rhodes restorers out here

obviously functionality trumps all, but when going for a restoration and you're replacing missing parts like legs, pedals, rod etc. would you go out of your way to source original parts that may be less aesthetic, or would you go for the shiny reproduction parts from the usual suspects. i know rhodes restorers are not shameful about their mods, retolexing in awesome colors and customizing to their hearts content, but how does this affect the value of the instrument?

in the vintage guitar world, there's no question that originality is a huge part of the value of the instrument. a refinish or reproduction parts could kill the value of a guitar. whats the feeling over here?