Lowrey C500 Pair One to keep, one to sleep. But which?

[RgrMt]

Hi,

Long time lurker, first post. So I will add some background around the technical questions within.

We could call this A Tale of two Sitties. It was the best of times, it was the worst of times.

I currently have two Lowrey C500/H25-4's. The best of times: The first one came sans flute voices from a passionate lady who looked like Bernini's Ecstasy of Saint Theresa when she talked about it. She and her husband were moving and couldn't take it with them. Oh and would I like to have the Leslie that they hadn't been using because it doesn't seem to work with the Celebration for 20 bucks? Um? yes? After a bit of work,That 50C was paired with my Conn once home! How lucky to get a Leslie designed especially for my Conn. Her C500 has No flutes, nice brass, esp. trombone! and quite fun to play these 70's organ meets synth sounds. But not everything works. Dug in and found a critical missing decoder IC keeping flutes (and quite a bit else) from working. Could tell the foam speaker surrounds were shot as well, so I started looking for a parts C500. Found one being offered for free and brought it home. It sounded and sounds wonderful! Thus begins the worst of times.

I originally started picking up organs for vintage parts to be used in other older Audio Gear. Pretty quickly that one-word drug, TONE grabbed hold of me and the rest is the probably not-unfamiliar sad story of too many organs, too little space, but a big smile and better understanding of the lady who sold me her Celebration. I now laugh when I think of Guitar players going after "Tone" and wish I'd been wired that direction. At least Guitars are small! I am sure I am not alone when I share that I've got organs I really should get rid of, but they just do this one thing, just a bit different, better than the others. I've consigned myself to the addiction, but will limit its scope by imposing space constraints. So one of the C500's has to go.

The pair sure look the same from the outside. Mostly. The newer one to me is actually the older one. It more completely works, but its cabinet is in rougher shape, and it doesn't have the newer extra keying-problem-solving PCB that the one sans flutes has. So of course the first idea is simply to plug in the IC from the actually older one to the newer and be done. After all the newer one is in better physical condition, with crisp and complete lettering on the aluminum around the stops and buttons, where the older one is worn. But upon inspection, I see that there have been a few issues with the flutes on this one, and a serviceman has written notes around the PCBs. Hmm. Maybe not such a good idea to plug the good IC from the old into the potentially bad board or power of the new. And as I play the older one, it feels better. But of course it is more fully working. Then I start to look into what its going to take to put the entire guts of the old into the newer case and discover that the old has wood core keys, where the new has metal/plastic. Or even just moving the printed aluminum extrusions from the newer to the older. This kind of conjoining or marriage between two organs is never easy, and in this case looks downright formidable!

So my question is, What to do? Which to keep? I am not new to electronics or organs and can troubleshoot and repair to component level. I'm going to check the power supply rails of the newer one with my scope to see if maybe this is the reason behind the repeated failure of its flutes over the years. I checked voltage levels already, but haven't done the full-on scope thing yet. If there is something obvious there, then the question is probably answered. But I thought I'd ask the Lowrey Guru's here if there are known issues I might not otherwise catch? Are the improvements in c500's between the wood keys and the added keyhold? PCB version worth trying to keep?

What this comes down to for me is the sense that the older one is a classic gem of the species, and the newer is lemon-ish. My technical mind recoils at this kind of "oxygen-free copper";-) conclusion, but my experience of one vs. the other leads me back there.

So what was originally going to be a chip pull and replace, from old to new; has become a harder decision. Now I'm asking for any and all advice.
I'm away from the paperwork, but I think the IC in question is something like a 33bit specialised shift register/multiplexer. Not a standard 4000 series to be sure!

If anyone has the Operators manual for these, I'd love to download it! I have the service manual.

Cheers, Roger

[lparsons21]

lowreyforum.com has the service manual but not the owner's manual.

Here claims to have it and even shows it in the list of manuals.

http://www.n8fan.net/item/lowrey-org...als-mx-1-free/

[Larrytow]

Hi RgrMt,

While I can't really be of assistance with your Lowrey dilemma ( they are not a brand I have much experience with - I'm more of a Yamaha / Allen guy ), I do want to welcome you to the Forum. You will find quite a number of very knowledgeable folks here, that have experience with all sorts of brands and models. You will also find that you do not suffer from OAD ( Organ Acquisition Disorder ) all by yourself - lots of us here have that condition as well !

[andyg]

Which console do you keep? The better one, of course.

Which organ do you keep? I think you already know. Effectively both, but one won't have a console and its parts will live on a shelf until needed. From what you say, I think you're in an ideal position to produce one perfect specimen of a great sounding organ. You go through each with a fine toothed comb listing the good and bad points of each and that will give you a guide to what bits come from which organ. Sounds like you're already doing that.

Over at the Yahoo Lowrey Forum, you'll find several C500 owners, who may well be able to give you some hands-on advice based on the issues that they've had. One or two are on here as well, but it's worth signing up over there if you haven't already done so.

Let us know how it goes, sounds like a long, but ultimately very rewarding project.

Andy G

[RgrMt]

Thank you Andy, Lloyd and Larry!

Hi,

I just want to thank the three of you for responding to my question!

Lloyd, I tried to download that Manual, but without success. They wanted me to join up and without knowing more about their site, I just couldn't do it. Too many bad experiences with unwanted payloads in that type of file download! But if you have used them before and can vouch for them, I'll go back and get it. Either way, Thank you.

Larry, Thank you for the welcome! I like Yamaha's too! I wonder if you know how the key wiggle vibrato works on my E4000? I haven't been able to source an owners or service manual for it yet. It's working fine. I'd just like to understand how they do it? Might be fun to combine it with after-pressure volume. Side to side key wiggle for vibrato, and up down wiggle for tremolo! I had to let my one Allen go due to space. It was the only Full AGO radiused pedalboard I had left. Sweet tone, that one. Early transistor model, but I can't remember the exact number.

Andy, I know you're right, but I'm getting lazier about doing complete rebuilds as I grow older. Thanks for the prod! I did join the Lowrey forum as you suggested and basically re-posted what I said here.

Thank you all again, Roger

[lparsons21]

Roger, I just found that site with a search. I've never actually used them and didn't realize you had to 'join up' to get a free manual. I looked at a couple sites I had used in the past, but they didn't have anything at all.

Sorry it didn't work out.

You might check on the Yahoo Lowrey forum to see if one of the participants there has that book. I know that some of them had C500's at some point in time.

[RODDDIEHL]

http://www.lowreyforum.com/manuals/C..._LOWREY_EN.pdf

This is 172 pages and takes a while to load

[healsing]

Hi,

Long time lurker, first post. So I will add some background around the technical questions within.

We could call this A Tale of two Sitties. It was the best of times, it was the worst of times.

I currently have two Lowrey C500/H25-4's. The best of times: The first one came sans flute voices from a passionate lady who looked like Bernini's Ecstasy of Saint Theresa when she talked about it. She and her husband were moving and couldn't take it with them. Oh and would I like to have the Leslie that they hadn't been using because it doesn't seem to work with the Celebration for 20 bucks? Um? yes? After a bit of work,That 50C was paired with my Conn once home! How lucky to get a Leslie designed especially for my Conn. Her C500 has No flutes, nice brass, esp. trombone! and quite fun to play these 70's organ meets synth sounds. But not everything works. Dug in and found a critical missing decoder IC keeping flutes (and quite a bit else) from working. Could tell the foam speaker surrounds were shot as well, so I started looking for a parts C500. Found one being offered for free and brought it home. It sounded and sounds wonderful! Thus begins the worst of times.

I originally started picking up organs for vintage parts to be used in other older Audio Gear. Pretty quickly that one-word drug, TONE grabbed hold of me and the rest is the probably not-unfamiliar sad story of too many organs, too little space, but a big smile and better understanding of the lady who sold me her Celebration. I now laugh when I think of Guitar players going after "Tone" and wish I'd been wired that direction. At least Guitars are small! I am sure I am not alone when I share that I've got organs I really should get rid of, but they just do this one thing, just a bit different, better than the others. I've consigned myself to the addiction, but will limit its scope by imposing space constraints. So one of the C500's has to go.

The pair sure look the same from the outside. Mostly. The newer one to me is actually the older one. It more completely works, but its cabinet is in rougher shape, and it doesn't have the newer extra keying-problem-solving PCB that the one sans flutes has. So of course the first idea is simply to plug in the IC from the actually older one to the newer and be done. After all the newer one is in better physical condition, with crisp and complete lettering on the aluminum around the stops and buttons, where the older one is worn. But upon inspection, I see that there have been a few issues with the flutes on this one, and a serviceman has written notes around the PCBs. Hmm. Maybe not such a good idea to plug the good IC from the old into the potentially bad board or power of the new. And as I play the older one, it feels better. But of course it is more fully working. Then I start to look into what its going to take to put the entire guts of the old into the newer case and discover that the old has wood core keys, where the new has metal/plastic. Or even just moving the printed aluminum extrusions from the newer to the older. This kind of conjoining or marriage between two organs is never easy, and in this case looks downright formidable!

So my question is, What to do? Which to keep? I am not new to electronics or organs and can troubleshoot and repair to component level. I'm going to check the power supply rails of the newer one with my scope to see if maybe this is the reason behind the repeated failure of its flutes over the years. I checked voltage levels already, but haven't done the full-on scope thing yet. If there is something obvious there, then the question is probably answered. But I thought I'd ask the Lowrey Guru's here if there are known issues I might not otherwise catch? Are the improvements in c500's between the wood keys and the added keyhold? PCB version worth trying to keep?

What this comes down to for me is the sense that the older one is a classic gem of the species, and the newer is lemon-ish. My technical mind recoils at this kind of "oxygen-free copper";-) conclusion, but my experience of one vs. the other leads me back there.

So what was originally going to be a chip pull and replace, from old to new; has become a harder decision. Now I'm asking for any and all advice.
I'm away from the paperwork, but I think the IC in question is something like a 33bit specialised shift register/multiplexer. Not a standard 4000 series to be sure!

If anyone has the Operators manual for these, I'd love to download it! I have the service manual.

Cheers, Roger

Hi Roger,

The question is how much time do you want to spend on this project? I spent 2 years of weekends getting a C500 that was in very poor condition up to about 90%. The 10% was beyond my ability because the boards from my instrument (circa 1996 early production) were slightly different from the circuits in the technical manual and I did not have the technical background needed to work without the manual. I was able to solve most of the problems but they weren't easy fixes. I also had a lot of help from one very patient and kind person. (I'm relating in the past tense because I no longer own the instrument. I relinquished possession to a young musician.) The fact that some of the circuits were different from the indications in the manual was a major problem for me.

You might want to check your Flute Percussion Filter Board on the earlier production model for anomalies against the technical manual. This would be important if you are in love with the idea of restoring older instrument.

Power supply: The older power supply might have a pot to adjust the voltages on the underside of the power supply. The newer power supplies might have a 12v regulator circuit replacing the pot. Once I completed a general overhaul of the power supply and adjusted the voltages it was true to form from then on. I tested the voltages frequently in the first year. I also discovered that the thermal compound in the power transistors had migrated into the contacts. So I cleaned and re-sat all of the power transistors. This one fix made a big difference in reliability. In my research I did not come across an endemic historical issue with the C500 power supply. I think the issues only relate to age. I am only mentioning the items/ issues other than the obvious that you might not be familiar with. Filter caps being the obvious.

There is a lot that happens to a 40 year old instrument that can't be predicted. For instance as you know the harness wires are wound on posts. They can appear to be clean but on my instrument the first half inch of wire under the insulation on some wires was badly corroded and brittle. In a few cases those wires were hanging from threads inside the insulation where I could not see the damage. I had to check every wire and post on every board for corrosion and resistance.

Broken wires are common on this instrument and that is the first place to look when trying to solve a problem that affects an entire set of voices. The second place is the ICs. They should be removed... the sockets cleaned... then re-sat carefully. Radio Shack precision cleaner does a good job on the sockets.

You might want to compare the board welds of the newer with the older production too. In my experience the welds on the later productions were less irregular with a better grade of solder. (I owned boards from later productions.)

As you may already know it is not that difficult to slide the entire chassis out of one cabinet and slide it into the better cabinet. It weighs about 250lbs and you will need another person's help to do that. You'll have to remove/ or cut about 8 speaker wires and that is the worst of it. It will also be a lot easier to access the 12" woofers for re-foaming when the chassis is removed. Shoot some WD40 into the channel before trying to slide the chassis out if you decide to do this.

If the woofers have been used in a deteriorated condition for a long time then they might not work well even after re-foaming. If this is the case they can be replaced using 12" Pyle -Reds.

Also at 40 years old the Leslie mechanism should be removed... the motor bearings/all bearings cleaned and oiled.

If the newer instrument sounds great now... then you are already ahead in the game. The C500 had accurate voices for its day and time. If the flutes already sound lush, clear and don't distort and if the solo preset voices actually sound like the instruments they are supposed to represent then you are in great shape. The percussions are very accurate and should sound magnificent. If the strings aren't harsh sounding and the chorus circuits are working that is another great thing. The difference between a functioning C500 and one that has deteriorated over 40 years is worlds apart. When functioning properly it blows the listener away. It's accurate. Mine ultimately had spectacular sound. Everyone that heard it responded with awe. I do miss it. (But alas I now have a Paramount 4/50 VTPO to keep my grief at bay. I too have the disease of finding the "Tone" and it seems my Technics GA3 and the Paramount 4/50 played simultaneously satisfies that need most of the time but of course not always) :-)

How much time are you willing to invest? This is a time consuming monster. A missing IC is the easiest fix... a few ICs are no longer available but many still are. All of the amplifiers are still available. I replaced all of them and had no issues with brand new amps. You already have one set of replacements and new ICs will work in quite a few instances. There are still some C500s out there. They do keep showing up on EBay and never sell and ultimately can be had for very little.

I hope this info helps in making your decision.

Good luck,
Rob

[RgrMt]

C500 keep? sleep?

Hi Rob,

Glad to see your reply. Thank you. Both of mine are in pretty good shape besides the problems I wrote. They do sound quite nice. It seems you were not so lucky at the start. I remember reading your story when I looked for information for the first C500. I will definitely check the boards I have against the Service manual; thank you for that tip.

Cheers, Roger

- - - Updated - - -

Thank you RODDDIEHL.

I am still hoping to find the Owners manual too. If you know where that may be found online, I'd be keen to download it.

Cheers, Roger