Author Topic: Wurlitzer 200a Microphonic and modified Power cable  (Read 144 times)

Offline Allenm

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Wurlitzer 200a Microphonic and modified Power cable
« on: May 19, 2017, 09:57:23 AM »
I just picked up a nice 200a from a fellow here in my town for $350. It is in fairly good condition, speakers were blown but the action and keys felt great, and the reeds sing more than my 200! The only issue I have besides the speakers are:

1. Someone has connected an attached grounded cable instead of the old 3 prong oval connector.

2. The whole keyboard is microphonic, tapping anywhere on the case or reed bar is audible in the line out, headphones, and speaker output. When playing keys the mechanical noise is put out through the speakers...annoying!


My first thought was to disassemble and clean entire keyboard, then install a new 3 prong IEC connector, ease a few of the balance rail holes, then reassemble making sure all screws are attached properly and are not noisy. I'm not really sure what to do if the problem persists. Any thoughts?

Offline Allenm

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Re: Wurlitzer 200a Microphonic and modified Power cable
« Reply #1 on: May 19, 2017, 10:28:04 AM »
 :D
« Last Edit: May 19, 2017, 10:48:38 AM by Allenm »

Offline pianotuner steveo

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Re: Wurlitzer 200a Microphonic and modified Power cable
« Reply #2 on: May 19, 2017, 03:28:49 PM »
Before doing all that, I would remove the amp board and check for cold solder joints. Carefully reflow the solder if you know what you are doing. If you don't know, have an experienced tech do this so that you don't accidentally short parts out. I'm pretty sure that will cut down or eliminate the microphonic issue if done properly.

Don't start modifying anything. Is it possible someone grounded the power wire to the wrong spot?
1960 Wurlitzer model 700 EP
1968 Gibson G101 Combo organ
1975 Rhodes Piano Bass
1979 Wurlitzer 206A EP
1980 Wurlitzer 200A EP
1980 Wurlitzer 270 Butterfly Grand
2000 Yamaha acoustic piano
2004 Hammond XK3
2009 73A Rhodes Mark 7
2009 Korg SV-1 73
....and a few guitars...

Offline Allenm

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Re: Wurlitzer 200a Microphonic and modified Power cable
« Reply #3 on: May 20, 2017, 09:48:46 PM »
Anyone ever seen this before? I lay it aside for the night and found this....

Offline pianotuner steveo

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Re: Wurlitzer 200a Microphonic and modified Power cable
« Reply #4 on: May 20, 2017, 10:12:30 PM »
That bracket is bent and the screw is missing. I would make sure the screw isn't rattling loose in there somewhere..
1960 Wurlitzer model 700 EP
1968 Gibson G101 Combo organ
1975 Rhodes Piano Bass
1979 Wurlitzer 206A EP
1980 Wurlitzer 200A EP
1980 Wurlitzer 270 Butterfly Grand
2000 Yamaha acoustic piano
2004 Hammond XK3
2009 73A Rhodes Mark 7
2009 Korg SV-1 73
....and a few guitars...

Offline Allenm

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Re: Wurlitzer 200a Microphonic and modified Power cable
« Reply #5 on: May 20, 2017, 11:18:48 PM »
Whats strange is it wasnt like this when I removed it. Maybe some one stepped on it but I doubt it. Anyways, I bent it back into shape so it fits well now.

Offline pianotuner steveo

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Re: Wurlitzer 200a Microphonic and modified Power cable
« Reply #6 on: May 21, 2017, 12:34:07 PM »
I hope they didn't step on the amp board.... That reminds me, it's possible that you have broken traces on the board, but I would look for cold solder joints first. Sometimes that is the only problem.

1960 Wurlitzer model 700 EP
1968 Gibson G101 Combo organ
1975 Rhodes Piano Bass
1979 Wurlitzer 206A EP
1980 Wurlitzer 200A EP
1980 Wurlitzer 270 Butterfly Grand
2000 Yamaha acoustic piano
2004 Hammond XK3
2009 73A Rhodes Mark 7
2009 Korg SV-1 73
....and a few guitars...

Offline Allenm

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Re: Wurlitzer 200a Microphonic and modified Power cable
« Reply #7 on: May 22, 2017, 03:31:17 PM »
I found some spots on the amplifier that look cold. Also the green arrow shows where there was a connection (not sure) between two points but has broken.

Offline pianotuner steveo

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Re: Wurlitzer 200a Microphonic and modified Power cable
« Reply #8 on: May 23, 2017, 04:18:55 PM »
Have you resoldered the board? The top left pink arrow looks like a cold solder joint. I can't tell about the others. I don't know for sure about the green arrow area, I don't have one apart to compare it to.
1960 Wurlitzer model 700 EP
1968 Gibson G101 Combo organ
1975 Rhodes Piano Bass
1979 Wurlitzer 206A EP
1980 Wurlitzer 200A EP
1980 Wurlitzer 270 Butterfly Grand
2000 Yamaha acoustic piano
2004 Hammond XK3
2009 73A Rhodes Mark 7
2009 Korg SV-1 73
....and a few guitars...

Offline tjh392

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Re: Wurlitzer 200a Microphonic and modified Power cable
« Reply #9 on: Yesterday at 04:08:35 AM »
Not sure why they jumped those two leads. They're connected by the trace and I can't see any obvious damage to the board in that area. Here's a photo for reference:



I agree on both of those solder joints, they need reflowing. Also worth posting an image of the pre-amp board too.



Rhodes Stage 73 1975 with Satellite System, Wurlitzer 200a 1976, Hohner String Performer