Wurlitzer 200a stopped working

Recording Techniques, People Skills, Gear, Recording Spaces, Computers, and DIY

Moderators: drumsound, tomb

Post Reply
bassist001
audio school graduate
Posts: 15
Joined: Tue Nov 17, 2009 10:18 pm
Location: Redding, CA

Wurlitzer 200a stopped working

Post by bassist001 » Mon Jan 25, 2010 7:18 pm

so i decided that i was gonna redo all the grounding wires going between all the sections of the harp and what not, cause the old connections and starting to break off from being so old. anyways piano worked fine minus the bad hum i thought might be from the grounding. but once i replaced the wire now the piano wont sound at all. its making power to the transformer. but not really sure where i would need to check in the circuit to find the problem. if any one know anything that would be awesome!
o and i tested the speakers and theyre making contact still too.

Nate Dort
tinnitus
Posts: 1039
Joined: Mon Mar 08, 2004 6:07 pm
Location: Detroit
Contact:

Post by Nate Dort » Tue Jan 26, 2010 4:18 am

Are you getting voltage at the reed-bar preamp? IIRC, it should be about 170VDC there.

ckeene
suffering 'studio suck'
Posts: 418
Joined: Mon May 12, 2003 2:15 pm
Location: Cambridge, MA
Contact:

Post by ckeene » Tue Jan 26, 2010 9:34 am

None of the tines are making electrical contact with the reed bar, correct?

bassist001
audio school graduate
Posts: 15
Joined: Tue Nov 17, 2009 10:18 pm
Location: Redding, CA

Post by bassist001 » Wed Jan 27, 2010 10:16 pm

ya so i checked and none of the reeds are shorted out. then i checked the voltage on the reed bar pre-amp and the wire that says 150v next to its only getting about 55v. and im guessing thats a bad thing ha ha. what cause that mean?

bassist001
audio school graduate
Posts: 15
Joined: Tue Nov 17, 2009 10:18 pm
Location: Redding, CA

Post by bassist001 » Wed Jan 27, 2010 10:17 pm

what could that mean. ha ha sorry

Nate Dort
tinnitus
Posts: 1039
Joined: Mon Mar 08, 2004 6:07 pm
Location: Detroit
Contact:

Post by Nate Dort » Thu Jan 28, 2010 5:29 am

Make sure point 21 on the board has continuity to the chassis, and that the red/yellow wire from the power transformer is connected to ground also at point x4.

ckeene
suffering 'studio suck'
Posts: 418
Joined: Mon May 12, 2003 2:15 pm
Location: Cambridge, MA
Contact:

Post by ckeene » Thu Jan 28, 2010 5:33 am

There's a very high impedence on the reed bar, and if you don't have a good meter with a high internal impedence, the DC reading can appear lower than it really is. If you're reading any voltage at all on the preamp, it would seem there's not a short between the reeds and reed bar.

Is the main amp working? Can you get any sound out of the amp just from tapping the input point on the PCB with a screwdriver?

Also are you sure the grounding wires on the reed bar are connecting to an electrical ground?

bassist001
audio school graduate
Posts: 15
Joined: Tue Nov 17, 2009 10:18 pm
Location: Redding, CA

Post by bassist001 » Tue Feb 02, 2010 9:59 am

well sorry it took me so long to get back. i was out of town. but awesome so i checked all of the things and found that there was no sound what so ever coming out of the speakers. so closer inspection i found that the 2 speaker wire had shorted out together down underneath by the aux and headphone jack. so now its making sound. but its still got a good amount of hiss. its not 60Hz. so im guessing i just need to fix all the grounds and go from there. but would swapping some of the resistors for new carbon comp help? and would swapping some of the transistors and caps help fix that too?

THANKS for all your help! :D

Post Reply

Who is online

Users browsing this forum: No registered users and 15 guests