power supply for Rodgers E330TM

[Geremia]

Similar to what Ed reported here

An organist turned the key on the power switch and got a brztt and puff of smoke.

, the key power switch and power supply of our 550 watt Rodgers E330TM burned out. The 1.6 amp slow-blow fuse was also faulty.

What sort of power supply can I buy for it? How do I wire it to the preexisting multi-prong plugs? Is a schematic diagram for this organ available somewhere?

thanks & merry êž³mass

[plymouth53]

Geremia,
I looked at my schematics for a Rodgers 333 Theatre, which is the same vintage as your 330, and
there are several voltages from the supply. Plus/minus 12vdc, plus/minus 24vdc, plus 15vdc, 18vac.
Two supply version were listed, Type VII and Type VIII. The power on key can switch the AC input directly, or there could be a power relay option connected to the key switch.
The relay would switch the main AC power load.
You mentioned a blown 1.6 amp slow fuse. I don't see one that size for the power supply. Is that from one of the speaker amplifiers?
If so, that may point to a shorted bridge rectifier in the amp.
My thought would be to troubleshoot the switch and check all the power supply voltages. Did any power supply fuses blow? Parts for the supply and amplifiers are available.
Both can be repaired. It would take several supplies to duplicate all that is needed.
Please note, my information is from Rodgers 333 schematics, so there could be differences in the 330.

[Geremia]

I looked at my schematics

Is a scan of those schematics available for download somewhere?

for a Rodgers 333 Theatre, which is the same vintage as your 330, and
there are several voltages from the supply. Plus/minus 12vdc, plus/minus 24vdc, plus 15vdc, 18vac.
Two supply version were listed, Type VII and Type VIII.

What do those types mean?

The power on key can switch the AC input directly, or there could be a power relay option connected to the key switch.
The relay would switch the main AC power load.

Here's where the key power switch was (next to the memory key switch):

You mentioned a blown 1.6 amp slow fuse. I don't see one that size for the power supply. Is that from one of the speaker amplifiers?

It was on the back side of this:

If so, that may point to a shorted bridge rectifier in the amp.
My thought would be to troubleshoot the switch and check all the power supply voltages. Did any power supply fuses blow? Parts for the supply and amplifiers are available.
Both can be repaired. It would take several supplies to duplicate all that is needed.

What are and where are are all the supplies?

thanks for the help

[plymouth53]

Looks like more differences between a 333 and 330, then I realized.
The Type VII (7) and Type VIII (8) are different revisions of the same power supply.
The voltages I noted all come from that power supply. It's one large single chassis unit.
Can you swing out the panel with the speakers connections, and take a picture of
where the 1.6amp fuse is located. Also, look inside for the power supply. Maybe mounted
on the console side walls or the bottom. It would be a large unit with many wires connected to it.
You might have to swing out all the panels to see it. Take a picture with the panels open.
I noticed the speaker wire connections look modified . Some do not have Amphenol connectors.
Is the audio feeding a PA system in the church, or different amplifiers?
I can scan the 333 power supply schematics, but maybe another user has a match for the 330.
Let's see what type of power supply you have.
It might take a while to determine what failed.
Check Ebay, “ Rodgers organ” postings.
There is a power switch from a Rodgers 725 that might match your bad one.

[Geremia]

Is the audio feeding a PA system in the church, or different amplifiers?

Yes, it's connected to PA with two large headphone jacks.

[John Drabik]

I looked through scanned schematics someone sent to me (after contact on this site 2 years ago. Still appreciate that!), and two non-330 manuals I've picked up since. The scanned schematics did not have power supplies. The 32/D and 220 manuals (similar vintage to yours) show Type III and Type IV power supplies. You asked what those numbers mean - it's basically just a model number for the power supplies. You should repair (or replace) with the same Type power supply and/or info.

Of the two, the Type IV seems to be closest to what is in my Providence 330. I can't see the label on mine - you may be able to find text on your EM330 power supply that indicates the Type though, which you should post here. The schematics in these manuals, again, NOT for a 330, show outputs for +12, -12, +30, -30, and +15 volts. By the way both show only 1 fuse, a 5-amp SloBlo in the primary line. All the other protection devices appear to be circuit breakers. There may be fuses on the output sections, but I don't see any in the materials I have.

I've been re-creating Providence 330 schematics in an electronic CAD system (Kicad for Linux, also available on Windows, etc.) and the voltages listed above are the only ones showing on pages I've converted so far. I could scan and send the Type III or Type IV pages to you (it's probably best not to send them through this site due to the size, but I have no objection to doing that). Scans tend to be hard to read but if I do them at hi-resolution (600 dpi) it may work. I have not entered (and didn't plan to enter) the 330 power supply into Kicad, but may consider that since mine also had some issues due to mods by the prior owner, and forced repair of a bridge rectifier when I got the organ a couple of years ago.

There could be many causes for a fuse popping after years of otherwise normal use. It *could* be that the organ was moved or a cable was stepped on, or other changes that would cause a short. Cables age and get rigid and dried out. Another possible cause is an old electrolytic capacitor that has simple given up the ghost. They do age! If you've noticed any hum lately, it could have been a sign that one was ready to blow, taking fuse (circuit breaker?) and power supply with it. Even if not, if those capacitors haven't been replaced, you should *seriously* consider doing that! These organs are approaching 50 years old (some of the scanned pages I worked from to get started showed dates back as far as 1968! Most of the 330 series would have been around 1971 vintage. Those caps could easily be dried out (I replaced several in my power supply, and part of the reason for capturing schematics is so that I can perform this type of maintenance going forward. The 330 series is the best of the Rodgers analog instruments (even better than the 660 and 990, voicing wise, IMHO) and is well worth keeping.

If you have to get a replacement power supply, eBay is probably your best bet. If you do get one, be sure to verify that the electrolytic capacitors are not dried up, and replace them before you plug it in. If you have to replace the entire power supply system, that is possible but not recommended. However, note that the Type III and Type IV appear to have regulated outputs only for the +12 and -12. All the other voltages (+30, -30, and +15) are unregulated. All of these voltages are designed for some hefty currents though! Also, if you do have to replace the power supply, you will want to find *linear* power supplies, not modern "switched mode" power supplies, and the newer supplies might be more compact but will result in considerable hum and noise in your audio that is very difficult to completely filter out (don't ask me how I know this. ;-)

[toodles]

If you need the 330 tech manual, I have pdf files of it--it is in several sections. Not, perhaps, the best scan, but the price is right. Send me a PM with your direct email and I will forward the sections.

Toodles

[plymouth53]

Geremia,
The 1.6amp fuse in your picture, would be in the common control wiring that turns on the Rodgers speaker amplifiers. The amplifiers are in standby until the console is turned on. 15vdc from the organ power supply, then goes to a turn-on relay in each amp. Since the organ is using the church PA system for audio, I guess there are no Rodgers amps in use. Maybe a past wiring short or amp problem blew the fuse. The fuse could be replaced as a test to confirm there is not a problem in the console, but without an amp connected, the fuse has no load. It's possible your only issue is a worn out power switch, but did something in the power supply overload and burn out the switch? Bench testing the power supply would mean removing it and measuring voltages. Not a quick task. If you have a chance, a picture of the console inside might help. Usually there is a model number printed on the power supply chassis.

[Geremia]

Type IV seems to be closest to what is in my Providence 330.

Yes, mine is a Providence 330, too; the company verified this based on the serial #.

Where can I buy a Type IV power supply?

[toodles]

You could try Matt C. Neill at MCN Systems. He is not cheap, but he has a lot of Rodgers parts. Website: http://www.mcnsystems.com/

His email is sometimes spotty, so if you don't get a response in a day or so, try giving him a call.

[John Vanderlee]

I have never seen a power supply yet cannot be fixed unless it is a transformer, which can get pretty pricey. Common failures are the bridge rectifier or capacitors which cause blowing fuses. it would be worth it to have an electronics person look at it.

[Geremia]

We got a power supply that works, but now we have some other (related?) issues: lowest Eâ™ keys on all three keyboards work intermittently. Most of the pedals don't work. It doesn't seem to be a mechanical or electrical contact issue.

[toodles]

If all E-flat notes are intermittent regardless of stops, it is most likely in the multiplexing circuit for that note. If it is only on specific stops, it is something else. Do sub and super octave couplers reproduce the same issue on the same musical notes (i.e., does the problem follow the couplers or is it still the same key?).

As to the pedals, I'd check to see that the pedalboard is level. It might need to be shimmed at the front or back. You can check for mechanical versus electrical issues by moving the pedals away from the console and testing the magnetic switches with a strong magnet.

[Geremia]

If all E-flat notes are intermittent regardless of stops, it is most likely in the multiplexing circuit for that note.

The lowest Eâ™ keys are always intermittent, regardless of stops. The mid-range keys work well. There are some high-range keys that are intermittent on some stops.

You can check for mechanical versus electrical issues by moving the pedals away from the console and testing the magnetic switches with a strong magnet.

The pedals seem to work mechanically, but perhaps they aren't aligned to the switch.
thanks

[toodles]

The 330 uses a time-share system (technically called multiplexing) to carry all division keying information on 61 wires. All divisions (great, pedal, swell, and choir) use the same set of 61 wires to connect the keyboards to the keying system,. A clock cycles through the 4 division keyboards in sequence and latches the outputs of the 61 wires at the keying end. Thus, if one note is having problems on all divisions regardless of the stops being used, you look to a problem within that time share system. Each key connects to the set of wires by isolation through a diode (one for each note, each keyboard). If that diode intermittently shorts to ground, it can affect all divisions.

You can try disconnecting (one at a time) the keyswitch for the problem E-flat on each division. If disconnecting one division's E-flat makes all the others work, then that division has a bad E-flat diode, and you replace it and problem is solved.