Question about Wurlitzer Schematics

Q&A about all types of jukeboxes: Wurlitzer, Seeburg, Rock-Ola, AMI, and more.



Topic author
lyonsronnie
Junior Member
Posts: 21
Joined: Sun Sep 08, 2013 8:49 am
Location: Charlotte, NC, USA

Question about Wurlitzer Schematics

by lyonsronnie » Tue Sep 10, 2013 5:13 am

Hi folks!
I have a Wurlitzer 2800 I'm about to recap the amp on (and the junction box) and I'm curious about something on the schematics.

As you know, most of the caps in the amp can be replaced with mylar or film caps, and are non polarized. The electrolytics, though, are usually polarized.

On the schematics, in some places, the electrolytics have the positve direction marked. In many places though, the electrolytics don't have it marked (on the schematic)....

In the places where it's NOT marked, it appears all of those caps on the schematic connect to ground.

My question is, was it common practice on these older schematics, to 'assume' that if the cap is connected to ground, that the ground lead goes to ground? Every cap in the scematic that's electrolytic, that doesn't specify polarity direction, is directly connected to ground.

Any help appreciated, hope the question is clear.


Ron Rich
Forum Moderator
Posts: 8196
Joined: Sun May 06, 2007 11:31 pm
Location: Millbrae (San Francisco area)CA, USA

Re: Question about Wurlitzer Schematics

by Ron Rich » Tue Sep 10, 2013 5:09 pm

Ronnie,
The question is clear as a bell--the answer, however, is not--In WurliTzer's case, that is the way they drew them--other companies may vary-- Ron Rich


Rob-NYC
Senior Member
Posts: 1844
Joined: Sun Sep 25, 2011 3:05 am
Location: Manhattan, NYC USA

Re: Question about Wurlitzer Schematics

by Rob-NYC » Tue Sep 10, 2013 7:47 pm

In Wurlitzers of that era the amplifier was totally conventional, negative-ground.

However, for some reason they used a positive-ground for the low voltage DC so any electrolytic in the stepper or junction box must be carefully examined as they are connected positive ground.

Rob/NYC
"If we believe absurdities, we shall commit atrocities" -- Voltaire


Topic author
lyonsronnie
Junior Member
Posts: 21
Joined: Sun Sep 08, 2013 8:49 am
Location: Charlotte, NC, USA

Re: Question about Wurlitzer Schematics

by lyonsronnie » Tue Sep 10, 2013 11:11 pm

Thanks for the info. Tell me if my logic is correct, so I'll know how to proceed in the future.

I'm thinking, that if you have an electrolytic, you should always connect the negative side, to whatever part of the schematic has the lowest voltage potential. Using that rule, I should be able to figure it out... does that sound correct?


Rob-NYC
Senior Member
Posts: 1844
Joined: Sun Sep 25, 2011 3:05 am
Location: Manhattan, NYC USA

Re: Question about Wurlitzer Schematics

by Rob-NYC » Wed Sep 11, 2013 2:41 am

That's correct.

Rob
"If we believe absurdities, we shall commit atrocities" -- Voltaire

Who is online

Users browsing this forum: No registered users and 6 guests

It is currently Fri Oct 07, 2016 12:32 am