Wirlitzer 200 electronic piano

[miltown]

Hey all just picked up a Wirlitzer 200. Of coarse it doesn't work. Well it does but doesn't. 1st I need some power transistors. The MJE 2011, 2021, 2371. That's TR 8, 9 , and 10. Of coarse they are not really around but there is some replacements. I guess my first question is anyone have any knowledge of these. There is alot of info on the internet but I still can't seem to find an answer to the question of cross referenced transistors for the replacement. In the manual it states 2N4919.2N5191,2n5194. I'm not sure if they are saying that they are replacements or they are old transistors and then they switched to the MJE series. Included is a link to the repair manual. Page 31 and 30 are the relevant pictures and info. Any talk would be appreciated. And yes I did call Morelocks but they are slow to respond. Still waiting on them.

Electric Pianos - Wurlitzer Manual
Thanks
paul

[J M Fahey]

All are TO220 transistors (or the similar slightly smaller Motorola package)
The MJE2371 is a 3 amp transistor, a TIP 32B or C will do nicely.
The other two are 5A ones, TIP41/42 B or C will do.
Pinout is as on (printed) Page 29 or (PDF) Page 31.
Good luck.

[miltown]

Thank you that helps greatly. Now to order. I'll post how it goes.

[kurtdaniel]

nice pick dude.. good luck with the fix..

[miltown]

Thanks man. Yeah I forgot to get back but the transistors worked well. It sounds good. It was noisy after I replaced the power transistors so I replaced transistors 1-7 and all is good now. Thanks for the comments and JM thanks again.

[kurtdaniel]

I have the 207 teacher edition which i use for my piano lessons before,, anyone know how much I could sell it for?? Works great!

[Rhodesplyr]

The more I work on Wurlies, the more I'm moving towards the position that some of the redesigned aftermarket amplifier modules available for them might be the way to go. They're a bit too notorious for transistor failures for it to be the case that it's just the transistors. I've been told by several people who understand solid state circuits better than I do that inadequate design is the underlying problem. Actually, my impression is that the older circuits that more closely resemble tube circuits, with capacitive or interstage transformer coupling/isolation between each stage, like the 140B, can be more reliable than the designs in which they attempted to eliminate capacitors and DC couple the amplification stages.

[J M Fahey]

To be more precise, *early* SS power amp designs were unreliable because they did not understand (yet) Zobels, series inductors, heatsinking, thermal tracking, etc.
Later they got better
And as you say, you must take care of the proper preamp but beyond that, you can hook *anything*.

[Rhodesplyr]

JM--I'm not trashing SS power amps as a whole, but, in terms of Wurlitzer Electric Pianos, the improvement over time wasn't that impressive. Rhodes Suitcase Pianos from the same era don't blow up quite as often :-) What I was trying to say about Wurlitzer is that as they followed design trends from more isolated amplification stages to DC coupled stages, I don't think that they kept up with what needed to be done to make DC coupled stages stable.

[J M Fahey]

Fine with me
What I was hinting at (maybe somewhat obscurely, sorry ) was not rebuilding that amp as a modern Wurlitzer, but replacing it completely.
I guess you will still need the preamp, because of the peculiar pickups.

[Rhodesplyr]

What I was hinting at (maybe somewhat obscurely, sorry ) was not rebuilding that amp as a modern Wurlitzer, but replacing it completely. I guess you will still need the preamp, because of the peculiar pickups.

Oh, I agree completely. The more I talk with musicians who've owned Wurlitzer Electric Pianos, the more I hear, "I love the way it played, but it broke down all the time." A preamp is needed, but they were never anything special. The only thing they have to be protected from is a transient pulse from the capacitive pickup in the event that it gets shorted to ground, as often happens if a reed is misadjusted or if a metal whisker gets into the pickup area.

I haven't made a careful survey of them, but there have been several makers of aftermarket units that completely replace the original electronics, from preamp to power amp.

[therealrx]

Thanks man. Yeah I forgot to get back but the transistors worked well. It sounds good. It was noisy after I replaced the power transistors so I replaced transistors 1-7 and all is good now. Thanks for the comments and JM thanks again.

Hey Miltown. I'm a little late to the party but have the same question, and am wondering what you ended up using for transistors 1-7?