Circuit for an HMV Monaco
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Location: Melbourne, VIC
Member since 26 December 2010
Member #: 794
Postcount: 387
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Hi, does anyone have a copy of the circuit diagram for an HMV Monaco record player. The unit I have has very low audio output and I need to fix it.
Cheers
Scott
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Location: Sydney, NSW
Member since 28 January 2011
Member #: 823
Postcount: 6802
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Location: Melbourne, VIC
Member since 26 December 2010
Member #: 794
Postcount: 387
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Thanks GTC, I saw that pic and yes, no schematic. As I said it works, but very low volume. You reckon it could be any of the caps - I assume the transistors are ok given there is some signal
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Location: Sydney, NSW
Member since 28 January 2011
Member #: 823
Postcount: 6802
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Any original caps, especially electrolytics, from1966 would be well past their use-by date, even though they may still appear to be be good.
Usual procedure is to check power supply voltages, then work backwards from the speaker, injecting a signal.
The cartridge may well be cactus. Might even be as simple as a bad/corroded connection. Shouldn't be too hard to find the cause of the attenuation.
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Location: Melbourne, VIC
Member since 20 September 2011
Member #: 1009
Postcount: 1221
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Ducon branded electolytics & Ducon Red Caps are the biggest culprits for faults in 1960's Australian made solid-state gear. All Red Caps should be replaced as a matter of course.
If that fails, I'd turn my attention to the cartridge.
HMV H5-8E, JF-8E, C7-8E, U2-8E Service Manual
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Location: Wangaratta, VIC
Member since 21 February 2009
Member #: 438
Postcount: 5472
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There are two things in 60's sets that I am finding causing volume issues. Yes! to electrolytics these were used as coupling caps & dry out. The others are some small axial caps around 1/4" x 3/8" of similar values to the old wax paper type & are equally as reliable (not). Some of the Ceramics were also a worry and I am also finding Germanium Oscillator transistors failing.
Also check resistors and for the common dry joint (cracks on printed circuits).
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Location: Melbourne, VIC
Member since 26 December 2010
Member #: 794
Postcount: 387
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Thanks guys, re the cartridge, when I unplug it, I get the low signal. When its re connected there is no signal at all.
Will replace the electro caps and check the rest.
Hopefully a schematic turns up to so I can at least check volts etc.
Cheers
Scott
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Administrator
Location: Naremburn, NSW
Member since 15 November 2005
Member #: 1
Postcount: 7451
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Service manual uploaded to post #5.
‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
A valve a day keeps the transistor away...
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Location: Melbourne, VIC
Member since 26 December 2010
Member #: 794
Postcount: 387
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Thanks guys - much appreciated.
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