Wurlitzer 2300S without sound

[knucklehead]

Hi there! Hoping you are all doing fine!

I have a suddenly muted W2300S, after several years of quite proper operation.

Being rather ignorant, my "plan" is to recap the 534 amplifier but before I go clueless in this spending and work, I was thinking about describing everything I could observe, with the hope an expert gives me a hint about something to check before:

* Selection & play (movements) of records work fine
* I can clearly hear the record/music from the needle assembly but the speakers would not play any sound
* The amplifier is powered on, all bulbs glow & heat, a low/reasonable hum is heard at the loudspeakers
* The reset at the amplifier button operates, the fader switch does a clipping noise at the loudspeakers when I change between A, B, C, D, PHONO ONLY mode.
* Actually the loss of sound at the speakers started due a problem in the fader switch: the circlip at the end of the switch shaft fell out, positions between A, B, etc, were with it not longer granted, I started to jiggle the switch during operation which created rather loud clipping at the beginning before the sound was definitely lost (and it is where I believe I caused a damage)
* I fully disassembled the fader switch and carefully cleaned it (it was very dirty). I tested continuity and despite showing to be the switch now in nice and clean condition, the sound at the speakers has completely disappeared as stated...
* Removed all fuses for visual inspection and none in burned out

Are the capacitors suspicious? Or rather an specific bulb? By the way: all bulbs clearly glow in the dark - is this a "good sign" for a healthy bulb or a shot dead bulb would also be glowing.

Please help me and let me know if anything can be tested, prior buying caps and/or bulbs... I will be glad and thankful to report the results!

Thanks to everyone!
 

[frankb]

Hi Christian, I have a 2300S that I did a ground up resto 4 years ago. It was not easy. That stereo amp is awesomely complex. Rebuilding it is not for beginners. That being said, if these problems began with the fader switch failing why not double or triple check what you did cleaning that switch. Look for something grounding out the switch. Use your ohm meter. Possibly try jumpering the cabinet speaker directly to the 'Phono Only' leads from the output transformers. Regarding tube filaments, I've been working on tube amps for over 30 years and of course encountered loads of bad tubes; so far, only one of those bad tubes actually had a blown filament.

Frank B

[knucklehead]

Thanks Frank. Good to know about the tubes and wise advice about the “triple check”. I will certainly do!

[frankb]

Christian,  I was thinking....  Wurlitzer did away with that very complex fader switch starting with the 2600 machines.  I don't know how good you are around schematics but if you are never going to hook your machine up to constant voltage external speakers, simply bypass that fader by connecting the RCA jack outputs directly to the 'max output' leads of the amp output transformer secondary leads - the 'max output' leads would be the ones connected to the 'phono only' position on the fader.  Of course its stereo, so 2 output transformers and a max output lead from each transformer secondary.  Hehe, the hell with that fader!

Frank B

[knucklehead]

Hi frank. Thanks so much for taking the time. Even if i am a „big fan“ of original condition, a non working juke is no deal neither… your suggestion is very welcomed and certainly the next step i will try! I couldn’t find a replacement switch in the bay so this will be the most practical thing to do… thx again!

[knucklehead]

Reporting myself back, Frank, and all those trying to help me! I bypassed this morning the fader switch with the hope I had messed it up while cleaning it last time, but unfortunately: nope! The missing audio at the loudspeakers persists...

I am 99% sure the bypassing was done properly as I nicely respected the contacts of the original fader switch while in the position "Phono only", but just in case here briefly described for sanity check: from each of the both transformers (this is a stereo W2300S), 8 wires come out. I cut and isolated 7 of them and just left the red clothed one ready for connection. From the main PCB of the amplifier two thin wires (one grey, the second one brown) were connected to the fader switch. I cut them and left ready for connection. Finally, the two wires from the RCA sockets for the connection of loudspeakers were also cut and left ready for connection. The bypass was then done by creating two junctions, each of them connecting one of the red transformer wires, one of the wires from the PCB and one of the wires to the RCA sockets towards the loudspeakers.

Symptoms remained pretty unchanged:
* jukebox operates mechanically as should do: picks-up, plays and returns the record
* the music is heard at the needle assembly
* the amplifier is switched on: hums, all bulbs lit on, nicely heating
* operating the volume switch has an effect on the loudness of the hum at the loudspeakers but no music at all is audible at them
* I basically (carefully) jiggled everything I could do while a record was being played: RCA connectors, loudspeaker sockets, balance switch, treble and bass switches, mute socket plug, volume switch...

I would be only thankful if somebody would advice the next recommended step!

Thanks to everyone and have a nice WE!

[jukenorman]

Hi Christian,
Whatever is your problem, it is clearly affecting both channels although as you say, there does seem to be some life in the amplifier. Can you try another input to prove the cartridge, even something as simple as sticking a small screwdriver into the phono input sockets (to produce noise!) with the machine in play mode? If the phono cartridge and its wiring is good (it might be something as simple as a missing ground), then you probably need some technical expertise to repair the amplifier.

Norman.

[knucklehead]

That was enlightening, Norman! Thanks! The "magic" when clueless amateurs (like me) reach in this forums people who know what they are dealing with...

I connected in the amplifier's "Input A/B" RCA sockets a walkman (to remain partially vintage, huh!) and while a record was being played (but not heard), the U2 tape in the old Sony WM-2 was nicely heard in the juke's loudspeakers with all functions of the amplifier (treble, bass, balance, volume all of them properly working)! --> ampli: check!

So my problem is upstreams between the amplifier and the cobra... I cleaned throughly the large socket on the top of the amplifier that comes from the needle but was of no use. I jiggled the cable between needle and amplifier but was also showing any effect (neither music nor noises)... Where do that line often fail? Again: the needle touches the record as the "mechanical sound" of the record is clearly heard in the area of the needle/record...

Thanks again so much for patiently walking me through it!

[jukenorman]

Hi Christian,
Just for accuracy, the cartridge is not a Cobra; if it's original it's a ceramic Sonotone. There are a couple of intermediate RCA plugs/sockets at the back behind the tone arm - you could try your Walkman there to narrow the problem further. Take a good look at the back of the phono cartridge also to check whether a wire has become disconnected.

Norman.

[knucklehead]

Done, Norman and All! It was indeed a loose contact! The 2300S is working again! I have no enough words to thank all of you for the huge help!!!

[jukenorman]

Well done Christian, we like a happy ending!

Norman.