Author Topic: No vibrato in 206a after installing the kit....where to start trouble shooting  (Read 393 times)

Offline DougDA

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As the title states, I ordered a vibrato kit and installed it per the youtube video series.   

After testing it, I have no vibrato at all.  The rest of the piano works normally but no vibrato effect.

How should i go about trouble shooting the issue?

Offline Alan Lenhoff

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Have you contacted the seller of the kit and asked for assistance? 

Alan
Co-author, "Classic Keys: Keyboard Sounds That Launched Rock Music" (Coming November, 2019)

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1965 UK Vox Continental;1967 Gibson G101 organ; 1954 Hammond B2; Leslie 21H; Leslie 31H; 1974 Rhodes Mark I Stage 73; 1972 Rhodes Sparkletop Piano Bass; 1978 Hohner Clavinet D6; 1968 Hohner Pianet N II; 1966 Wurlitzer 140B; 1980 Moog Minimoog Model D; 1977 Fender Twin Reverb; Vox AC30CC2X amp.
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Offline cinnanon

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I did it once, same thing. No vibrato. I said the hell with it and went Retrolinear and haven’t looked back.

Offline DougDA

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I got the kit from Morelocks and Janice there recommended i double check the direction (+/-) of all of the caps i installed .....which i did and they seem to be correct.

Now I've gone from no vibrato to no output at all....??

so far I've tried:  replacing the board fuses/fuse holders,   checking all of the solder joints on the board.


what should i check next?
« Last Edit: September 06, 2019, 08:34:05 AM by DougDA »

Offline cinnanon

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I got mine from there as well. I think the next thing to check is your bank account to see if you have enough money to buy a Warneck amp. Honestly I don’t know what to check. I guess you could make one of those headphone circuit testers to trace the signal path.

Offline beginnersluke

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I am not familiar with that kit, but I'll say a couple of things.

1. To turn a 206A amp into a 200A amp requires not just adding things, but removing them. Did you remove components as well?
2. Do you have a schematic? The schematic in the original service manual does a really nice job of laying out what's in the 200A vs 206A. You could/should go through and make sure you've made the necessary changes.
3. The schematic calls for the two sets of wires going to the Vibrato pot to be shielded. This wouldn't be at the top of my list, but I would check that the cables are shielded and that the pot is properly grounded. (I think the factory 200A install runs a wire from the ground lug to the body of the pot (which then connects mechanically to the amp rail).
4. If everything else is right, one easy place for it to go wrong is if the LDR is mounted improperly. This could easily result in sound, but no vibrato.
5. If I remember correctly, there's a trimmer pot for vibrato depth as well. Did you try changing that?

(The key here really is the schematic probably. #5 is a good place to start. Sorry, I was typing and thinking out-loud, or I might have put it #1.)

p.s. Since you put in all this work on an old amp, did you replace all the electrolytic caps? I'd recommend it.

Offline beginnersluke

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I'm not sure if this is still an issue or if you got it resolved, but one thing that can help with troubleshooting is seeing if you've got the oscillator working correctly. You should be able to test this by measuring the the two non-ground posts of the vibrato potentiometer with an ohmmeter. If you have an analog ohmmeter, you'll see the needle bounce. (You can still tell with a digital ohmmeter, since the reading won't be steady.)

Also, make sure that the wires coming back to the pre-amp are correct. The NON-ground wire actually connects right next to where it says "GND" on the pre-amp (referring to the screw connection to the harp), so it's not the hardest thing to mix up. (And if you did, I think you'd get sound, but no vibrato. Also, I'm legally obligated to mention that it's actually tremolo, not vibrato, but whatever... He he.)

Good luck buddy!