[Jukebox-list] some Wurly 2200 tech questions

[Jay Hennigan]

Rick Force wrote:
> Hi all,
> I have some tech questions for my 1958 Wurlitzer 2200. First off, there is a constant hum when the mute relay drops out. Doesn't change 
much according to volume, unless turned way up (then it squeals/ goes 
into feedback). It's not mechanical vibration as I selected an empty 
slot and the hum was there with the tone arm just suspended in air. Amp 
has been rebuilt (maybe something missed?) and has been modified to use 
a Wurlitzer 2700 series ceramic stereo cartridge (wired in mono). I just 
had a thought as I write this, could a tone arm wire be touching the arm 
(I believe its metal and not plastic...the arm is from a 3000). I'll 
have to check that.

If the level of the hum does not change with the volume setting, it is
not likely to be the tonearm/cartridge.  Most likely suspect is filter
(can) capacitors.  Were these replaced in the rebuild?

>    The next question is concerning the Wurlitzer #147 remote for this juke. The juke sounds great (except that hum), but as soon as that original remote is plugged into the remote socket of the 132 amp, the sound is too loud (can't even turn it all the way down, can still hear the music) and the sound quality is bad (not just distorted, but lack of highs...only bass and some mid range). I understand this is a miss match somehow (as the remote is set for the cobra circuit). How do I get that remote to work with the new mods? Warren Rowe who did the mods, said all mods were at the front end of the amp (the cobra circuit) and the back end (original volume control) was not touched. I need this remote as I need to put the juke in the corner and can't get to the back easily. My guess is that nothing needs to be done to the amp, but to the components in that remote. Why couldn't Wurlitzer just have the volume pot and cancel button in that 147 remote without any extra circuitry lik
e Seeburg and AMI/Rowe? The 147 seem too complicated for what it does (several resistors and caps connected to the pot terminals). You would think that all that could be removed and just connect directly to the pot (they use a double ganged pot...looks like a stereo pot, why would they do this in a mono juke?). Thank you, Rick.

The extra components and second gang are a loudness compensation circuit
that boosts the bass at low volume.  The pots are a different taper and
with the caps act as a combination tone and volume control.

The problem is likely mis-wiring or an open connection on the ground
(cold) end of the remote circuit.  Double check the functional wiring
as far as which leads of the remote go to which pins.  Often these get
modified in terms of color codes where someone in the field long ago
replaced or extended the wiring.

-- 
Jay Hennigan - CCIE #7880 - Network Administration - jay at west.net
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