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Post by shrimpeater on Sept 27, 2024 20:29:11 GMT
47760-1a amp . I've installed 2 amps and no sound.Checked stylus,and tomearm wiring,plug.
Do get small hum if I turn volume completely up.
Where should I start looking? How would I test the pickup cartridge?
Thank you
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Post by shrimpeater on Oct 3, 2024 20:21:04 GMT
So I got the service manuel,but it doesn't show where the power from supply to amp is. I could most likely at least check for power if I had a clue what color wire I'm looking for.
I have 2 of these amps that seem completely dead.
Shouldn't I get at least some sort of sound from them?
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Post by jukenorman on Oct 4, 2024 8:48:13 GMT
I don't have a diagram for the 47760-1A amplifier nor a 446 manual! Looking in the jukebox-world.de archive, the amplifier for a 446 shows a 12 pin connector from the power supply (red colour). Is there not an amplifier diagram in your service manual? Looking at a similar amp., the diagram shows DC voltage test points near that 12 pin connector for +30V, +15V and -15V. Can you find these and check the voltages? It could easily be a power supply issue that you have.
Norman.
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Post by shrimpeater on Oct 12, 2024 19:19:45 GMT
Yeap. Only getting +36 volts from 1 pin on connector. Now to figure out why.
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Post by jukenorman on Oct 13, 2024 9:26:07 GMT
In a way that's good news because the power supply would normally be much easier to fix than the amp.! The power supplies on these Rock-Olas are pretty basic but unfortunately I don't have the diagram for your one.
Norman.
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Post by Hildegard on Oct 13, 2024 12:56:41 GMT
For model 446 there are no extra schematics except for the amplifier (which has the part #46380-A, #47760-1A is originally for model 452). The schematic wiring diagram from model 444 has to be used for 446 as well. The part numbers for the power supply for 444 is 45475-1A and 45475-2A for 446. But the difference is only an extra handle on 446 amp. shrimpeater: Did you get a large wiring diagram with the manual? |
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Post by shrimpeater on Oct 13, 2024 20:47:40 GMT
No large schematics,just a small diagram in manuel.I found a bad recifier ( I thnk),but don't know the value.
I know wire colors and such,but hard for me to know what I'm doing when I have no voltages to look for,or where to look for.
Yeap. I'm lost
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Post by Hildegard on Oct 15, 2024 19:35:14 GMT
So which service manual for your 446 did you get? Just the "Supplement for 446" which is a few pages only showing differences to models 444?
Which power supply is installed?
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Post by jukenorman on Oct 15, 2024 20:54:19 GMT
You can find a diagram for the power supply here arcarc.xmission.com/PDF_Jukebox/Rockola/Schematics/ diagram 444-51b. Not the best quality but should be good enough to guide you (these are what were the Vern Tisdale schematics). 100V 3A bridge rectifiers will be fine for either, just pay attention to how the DC is connected, one is for the +ve DC voltage and the other for the -ve DC voltage. Norman. |
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Post by shrimpeater on Oct 17, 2024 19:07:45 GMT
That one is in the manuel.Looks like the bridge rectifier may be out.. I was wondering if this box might have taken on a surge since both selector coils were dead. Maybe somethng like that could have got to the amp or power as well.
Going to start checking power.Thanks.I'm determined to get this one fixed. It's a nice looker.
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Post by shrimpeater on Oct 22, 2024 19:02:00 GMT
It was indeed the rectifier. I replaced and now the box is working 100%.
It would be good to change the caps in the amp,but victory doesn't sell them for that model.
I have enough money in it anyway,and it sounds good.
Thanks for the help!!
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