Author Topic: Low volume and no vibrato on model 206  (Read 228 times)

Offline theseacowexists

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Low volume and no vibrato on model 206
« on: November 07, 2020, 09:42:23 AM »
Just wanted to see if anyone else had the same issue and how they solved it. An intact model 206 was brought to me to fix the low volume and have the vibrato knob added. Replacing all the electrolytics did not solve the volume issue and the new vibrato knob did nothing. Seems like the preamp is not getting the voltage that it should - only 8.4V is coming from the emitter and 9V from the base of TR6, almost half less than the 15.5V and 16.5V I should be getting. There's 22V at the collector, which is in the ballpark of 24V, so everything upstream of TR6 should be fine. However, this is causing lower readings at TR1 and TR3 also, which I figure might be affecting the vibrato as well.

Before I go hunting down some replacement transistors, is there anything obvious I'm missing? I might check the resistors around TR6 to see if they're OK, since I did find the two right before the vibrato pot (52 and 34) had almost doubled in resistance.


Offline theseacowexists

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Re: Low volume and no vibrato on model 206
« Reply #1 on: November 14, 2020, 07:04:25 PM »
Update: New transistors (and new resistors near T6) brought the volume back up to normal and voltage readings back to spec. Still no vibrato, and it brought out quite a hiss storm, which I suspect was there all along, but now I can actually hear  :P  Every resistor I replaced measured about 2X its original value, I suspect the other few dozen on the board are probably just as off. Will at least try replacing the ones in the vibrato circuit to see if that gets working.

Offline pianotuner steveo

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Re: Low volume and no vibrato on model 206
« Reply #2 on: November 15, 2020, 05:24:17 PM »
Did you buy a vibrato kit or just a knob and pot? The 206 models do not have vibrato built in.
1960 Wurlitzer model 700 EP
1968 Gibson G101 Combo organ
1975 Rhodes Piano Bass
1979 Wurlitzer 206A EP
1980 Wurlitzer 270 Butterfly Grand
2004 Hammond XK3
2009 73A Rhodes Mark 7
2009 Korg SV-1 73
2017 Yamaha P255
2020 Kawai CA99
....and a few guitars...

Offline theseacowexists

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Re: Low volume and no vibrato on model 206
« Reply #3 on: November 16, 2020, 07:22:11 AM »
I was under the impression that the 206 only needed the pot to enable the vibrato and the 206A needed the kit. The pot I've added to this 206 hasn't enabled the vibrato, but it does attenuate the piano's volume when turned to 50%, then back to full volume after 75%.

Offline pianotuner steveo

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Re: Low volume and no vibrato on model 206
« Reply #4 on: November 16, 2020, 05:39:21 PM »
I don't remember how to do it, I've only done it once and I believe it was a 206A...
Sorry..

Anyone else know what's going on?
1960 Wurlitzer model 700 EP
1968 Gibson G101 Combo organ
1975 Rhodes Piano Bass
1979 Wurlitzer 206A EP
1980 Wurlitzer 270 Butterfly Grand
2004 Hammond XK3
2009 73A Rhodes Mark 7
2009 Korg SV-1 73
2017 Yamaha P255
2020 Kawai CA99
....and a few guitars...

Offline marathonmusicgym

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Re: Low volume and no vibrato on model 206
« Reply #5 on: November 16, 2020, 07:01:28 PM »
I just did a 206 conversion last month. Sounds like you might want to check if the jumper between pin #12 and ground has been cut.

Check out this guide by TropicalFishVintage, might help out.

https://www.tropicalfishvintage.com/blog/2019/5/27/how-to-convert-a-wurlitzer-206-into-a-wurlitzer-200


Offline theseacowexists

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Re: Low volume and no vibrato on model 206
« Reply #6 on: November 18, 2020, 12:25:21 PM »
The jumper has been cut.