Wurlitzer CD Carnegie 1986 - FULL VOLUME ONLY ! ARRRRGH

[lozjenks]

Hi Guys, I have been through a number of the threads on here and apart from Barry and his almost complete electrical rebuild job I cannot find any relevant help on this !

Basically - The unit has been working well and then.... bang ... only full volume! and its LOUD man !

I have a trouble shooting guide for another similar box (OMT) and it recognizes the fault. The advise is to check the "remote volume regulator connections and cable" Basically this "regulator "comprises a small box with two 10k pots (one for each channel) and a lead to a Din plug. This DIN then plugs into the amplifier unit. The only ID and serial number I can see for this unit is that it is a Wurlitzer Compact Amplifier 40 200 000 00

I have checked thoroughly the lead for open/short circuits and also confirmed that the pots are working ok with a multimeter. The connection seems sound onto the amplifier board.

Any help appreciated please !

Loz

[Ron Rich]

How is your control box set up-- as a mono, or stereo control-- try switching it to the other, and see what happens ??

[lozjenks]

Thanks Ron, The only switch I can see to swop between Mono and Stereo are actually on the main Amplification board. I tried that and it is still the same I'm afraid.

I have tried to find a set of drawings for the machine, through the net, but so far no success.

I think my next step will be to take out the main Amplification board and see if I can see anything obvious on the solder side. It is not a small job, but I can see no option at present. I don't want to do it without a set of drawings really

Any other ideas? Really appreciate your help

Loz

[Ron Rich]

Hi Loz,
On the phono's rear, is there two volume control "pots" ? If so, is there also a switch in the center of them ? If so, that's a mono-stereo switch. Did you try finding "manuals"/info on that model from the suppliers listed in our FAQ's section ? Ron Rich

[whammoed]

Ron,
On my Wurlitzer that switch is a Stereo/2 Channel switch. This means you can control both left and right volume with just one pot or control them independently with both pots. It does sound like the issue resides with the volume control unit somehow. I've noticed a brief full volume output when switching between Stereo and 2 Channel with this switch.

Loz,

What amplifier does that machine have?

[Ron Rich]

Darren,
Yes-- if that switch is "half-flipped" I have heard full volume too---- Ron Rich

[lozjenks]

Hi Guys.... a great result... The volume issue is sorted out and the box is now working... following your tips (and a conversation with Barry Childs on another German forum...) I focused on the stereo/mono switch on the Amp board and cleaned that with contact cleaner. I also gave the Remote control Din Socket a good dosing of the same cleaner. This did the job

I went down a few dead ends though... very hard without a schematic ! I did find that there were two small electrolytic  capacitors beside the stereo/mono switch which it seems had been disconnected on one leg at some time. This may have been during the rebuild and refurbishment before I bought it 21 years ago. I soldered these back on and there was a lot of white noise through the amp continuously. so I disconnected them again. No idea what they do

After fixing the volume issue, of course the CD laser unit was skipping, not selecting, rejecting various discs etc. I have had this before. It appears that when you switch off the power during a CD playing (which I had to when the box went hyper volume !) The unit takes a while to sort itself out ! Strange but true ! Leaving the juke powered up, trying various discs, especially "Real" CDs not "Home made" discs seems to work... A curious situation, but once the box sorts itself out again... it is perfect !

I will keep searching for schematics, any help with that appreciated.

Whanmoed - The Amplifier has "Wurlitzer Compact Amplifier 40 200 000 00" as an ID

Thanks again all

Loz

[whammoed]

Loz,

Should be the I84 then.  Does it look like below?  What capacitors are lifted?  (they should have C### labels next to them.)

[phil]

hello frome France

the two capacitors are there for the pre amplifier part (for a single input) they are lifted because your amp works with the CD input

Phil

[kellymont]

Hi folks, I just see a picture of this Amplifier Board and felt I had to post. I have the exact same Amp in my Wurlitzer Sl600, to cut a vet long story short the green light and the red light are "on" is there a problem when the Red light is on? it only comes on when I plug in the mechanics board into the amp board and I'm sure they are not working correctly. Can anyone tell me the value of the fused on the board, mostly the ones fitted are 3.15a slow blow. Sorry for the extremely late reply. Steve in England

[phil]

on this amplifier, the fuses all have the same value, 3.15 standard fuses, no slow version