23rd Mar 2018, 1:25 pm | #122 |
Heptode
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Re: Dansette "Monarch"
The one fitted looks original as does the 'P' clip, and if the way it is positioned is inducing hum, that is original too.
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23rd Mar 2018, 1:58 pm | #123 |
Octode
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Re: Dansette "Monarch"
I still don't like the look of that soldered earth tag!
Anyway, remember that the picture in Post #106 shows the controls panel flipped over - when it is put back the right way up, all the mains cables run directly away from the controls.
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23rd Mar 2018, 2:06 pm | #124 |
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Re: Dansette "Monarch"
I think we're going to have to assume that this model of record player, or possibly just this particular example, suffered from excess hum from new.
That being the case all you can do is carry out the modifications suggested and see whether that makes a difference.
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23rd Mar 2018, 2:43 pm | #126 |
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Re: Dansette "Monarch"
I guess it's still all in bits on your bench/table?
Why not put the whole thing back together, taking care to route all the wires correctly, fit a cartridge and try it out properly - you may be surprised. It'll only take you ten minutes to assemble it and you can then make a proper assessment of any issues. |
23rd Mar 2018, 4:08 pm | #127 | |
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Re: Dansette "Monarch"
Quote:
Lawrence. |
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23rd Mar 2018, 5:25 pm | #129 |
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Re: Dansette "Monarch"
Measure the resistance (lowest ohms range selected on the meter) between the underneath of the record deck itself and the HT-ve track on the amplifier board. Just trying to gather as much info as poss.
Lawrence. Last edited by ms660; 23rd Mar 2018 at 5:39 pm. Reason: addition |
23rd Mar 2018, 5:45 pm | #130 |
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Re: Dansette "Monarch"
Difficult to see but it looks as though the mech chassis is not connected to the screened leads. The 3 centre pins on that connector usually have a shorting wire across them. If it's missing then connecting as you did to earth the slider of the treble control will cause a larger hum.
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23rd Mar 2018, 6:13 pm | #131 | |
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Re: Dansette "Monarch"
Yes, looking at the photo it looks like no connection to the deck chassis but I suggested the test to confirm, considering what was said in Post#86.
Quote:
Last edited by ms660; 23rd Mar 2018 at 6:17 pm. Reason: Quote added |
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23rd Mar 2018, 6:22 pm | #132 |
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Re: Dansette "Monarch"
I thought we'd been here in post#77.
EDIT. A simple visual check will show whether the three centre tags are strapped together. The wires going to the cartridge don't look right to me, but it could be an illusion due to shadows. Black and red to the centre tag is OK, but it looks like the blue and yellow wires are commoned on another tag. Has this been done so that both channels of a stereo cartridge can feed the mono amp?
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23rd Mar 2018, 6:52 pm | #133 |
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Re: Dansette "Monarch"
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23rd Mar 2018, 10:30 pm | #134 | |
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Re: Dansette "Monarch"
Quote:
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28th Mar 2018, 6:31 pm | #135 |
Octode
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Re: Dansette "Monarch"
One step forward …
Checked the connectivity of the screened wires tag strip to the record deck metal chassis and found it to be not as tight as it could be and possible contamination with some stray old grease. Disconnected the tag strip to enable a clear detailed picture to be taken – more on this later: - Cleaned the chassis and the metal on the tag strip to ensure good connectivity and screwed everything back up nice and tight - repeated some tests. 1. Shorted the wiper of the treble control to the chassis – reduced hum to an acceptable background hum. 2. Shorted the control grid of the triode (Pin 1) to the chassis - reduced hum to an acceptable background hum. 3. Shorted the control grid of the pentode (Pin 3) to the chassis – reduced hum to an acceptable background hum. Shorting wire removed after each test and loud hum resumed. Measured the resistance between the underneath of the record deck itself and the HT-ve track on the amplifier board - on the 200Ω range selected on the meter this was reading 0.02 Back to those controls and I measured the resistors again - my readings in RED: - R1 330kΩ 296kΩ R2 56kΩ 52kΩ R3 22kΩ 22kΩ I am assuming that these readings are o.k as are the two 200pF ceramic capacitors? Tried squirting as much contact cleaner as I could into the controls but access is extremely difficult - I've no intention of disassembling them! Got around to installing the new BSR X5M cartridge but wasn't sure about which leads to connect - looking closely at the tag strip picture above I decided to connect the black and red wires. The original TC8M cartridge had the red and blue wires connected?? Took the advice of Techman "Why not put the whole thing back together, taking care to route all the wires correctly, fit a cartridge and try it out properly - you may be surprised." - and I was as I managed to play an LP record. Some of the mechanical parts still need cleaned, greased and oiled due to some turntable stickiness but the sound wasn't too bad despite the hum. The auto changer and speed selector all appear to function correctly although I've since removed the cam, the turntable spindle and ball race to facilitate cleaning.
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28th Mar 2018, 7:49 pm | #136 |
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Re: Dansette "Monarch"
As stated in this link red and black is correct for a mono player:-
https://www.vintage-radio.net/forum/...94&postcount=8
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30th Mar 2018, 5:03 pm | #138 | |
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Re: Dansette "Monarch"
Quote:
If so, with the volume control set to minimum make sure the resistance between its wiper and chassis is low (up to a few Kohm is ok) If that checks out ok then with the volume control still set to minimum disconnect the record players mains earth connection (See Note Below) and power up and see if that makes any difference, if it doesn't then reconnect the mains earth lead. Note: Don't touch any of the record players metalwork or any part of the circuit once the mains earth is disconnected from the record player unless it's unplugged from the mains. Lawrence. |
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30th Mar 2018, 5:25 pm | #139 |
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Re: Dansette "Monarch"
Highly likely, but it looks as if you now have a 3 core fitted and all the better for it.
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30th Mar 2018, 6:42 pm | #140 | |
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Re: Dansette "Monarch"
Quote:
For the sake of my ongoing education, what was the significance of the tests to short the treble wiper and control grids to the chassis? I'm assuming there are no issues with the resistors and capacitors associated with the controls - two of the resistors are a bit low but not by much - is that an issue? All the lubrication according to the UA-15 Operating Instructions was done today with some help from Barry (Audio1950) - previous stickiness now resolved. As Graham (Station X) said several Posts ago "I think we're going to have to assume that this model of record player, or possibly just this particular example, suffered from excess hum from new." Seems too much like giving in to me but there comes a point when you just have to move on ... just need to get everything screwed back in place, adjust the tracking weight and give the record player another bit of a clean.
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