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Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment. |
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18th Jun 2018, 7:28 pm | #41 |
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Re: Murphy A855G- no sound.
If they go into the transformer they must be part of the windings.
I thought the primary and secondary windings were on opposite sides of the transformer, perhaps why I am confused.
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18th Jun 2018, 7:34 pm | #42 |
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Re: Murphy A855G- no sound.
I see you supplied that picture in post #29. Give me some time to think about things.
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18th Jun 2018, 7:41 pm | #43 |
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Re: Murphy A855G- no sound.
Post 35, why are two winding wires going to what is supposedly the 245 volt tag? Or is it the 225 volt tag?
Lawrence. Last edited by ms660; 18th Jun 2018 at 7:48 pm. Reason: additional comment |
18th Jun 2018, 7:50 pm | #44 |
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Re: Murphy A855G- no sound.
The short brown wire (245V tag?) in the picture in post #35 appears to go into the windings, but the short brown wire looks displaced towards the centre tag when compared to the picture in post #37.
Are they the same wire?
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18th Jun 2018, 8:02 pm | #45 |
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Re: Murphy A855G- no sound.
I'd say the centre tag in post #37 is the 225V tap and should have no EXTERNAL wires connected to it.
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18th Jun 2018, 8:04 pm | #46 |
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Re: Murphy A855G- no sound.
Looking at the plan view, the lower tag is clearly 0 volt, logically the next tag up would be the 225 volt tap and the upper tag logically would be the 245 volt tap but the upper tap looks to me as though there are two enamelled winding wires connected to it in the other close up photo, remote chance but could it be that they were connected wrong from new or at some point and that the center tag is actually the 245 volt end of the winding? Or the 225 volt tap has been connected to the 245 volt end of the winding, either would cause overrun.
Some resistance measurements with the deck motor feed disconnected would clarify. Lawrence. Last edited by ms660; 18th Jun 2018 at 8:26 pm. Reason: More additions |
18th Jun 2018, 8:06 pm | #47 |
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Re: Murphy A855G- no sound.
Possibly, but I can't reconcile the two pictures of the primary connections in my mind.
What's that double loop of wire close to the centre tag?
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18th Jun 2018, 8:15 pm | #48 |
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Re: Murphy A855G- no sound.
Inverted picture shows that the centre tag is the 225V tap.
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18th Jun 2018, 8:15 pm | #49 | |
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Re: Murphy A855G- no sound.
Quote:
I think the loop could just be a surplus length fold back that was stuffed into the brown insulating sleeve. Lawrence |
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18th Jun 2018, 8:25 pm | #50 | |
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Re: Murphy A855G- no sound.
Quote:
Back to the OP...……….
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19th Jun 2018, 8:32 pm | #51 |
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Re: Murphy A855G- no sound.
Hi,
Are the secondary windings the bottom of the coil windings, shown in post #29?, or are they somewhere else? If so I can post clearer pictures. Regards Stephen |
19th Jun 2018, 8:43 pm | #52 |
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Re: Murphy A855G- no sound.
Yes post 29 shows the secondaries.
The primary winding is connected to the 230v AC supply and the motor. One secondariy is connected to the diodes and the electrolytic capacitor. The other secondary is connected to the pilot lamp.
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20th Jun 2018, 9:50 am | #53 |
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Re: Murphy A855G- no sound.
What I'm interested in is the strands of wire shown in the second picture in post #48.
Do they go into the winding in a single place or in two places? Is the double loop of wire just doubled back excess wire? From the point of view of taking voltage readings on the secondary windings it probably makes little difference, so long as the strands are touching nothing apart from each other.
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20th Jun 2018, 11:37 am | #54 |
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Re: Murphy A855G- no sound.
Agree with you Graham, I was just trying to answer a specific question.
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20th Jun 2018, 11:42 am | #55 |
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Re: Murphy A855G- no sound.
No conflict intended. I'm sure we both want to see this player sorted. It's so frustrating not having it in front of one to prod and probe.
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21st Jun 2018, 6:20 pm | #56 |
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Re: Murphy A855G- no sound.
Hi, I have prodded the wire that was still in situ and found that it is identical to the other wire in that both feed the coil from a single strand of wire. I have taken a couple of new pictures to hopefully show this.
Thanks Stephen |
21st Jun 2018, 6:27 pm | #57 |
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Re: Murphy A855G- no sound.
I have the feeling looking at that wiring that the primary winding may have gone open circuit, especially with it not getting warm when power is applied.
You could test the without any power being applied with a multimeter on resistance range. The motor will need to be switched off or disconnected. See what other opinions are though.
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21st Jun 2018, 6:33 pm | #58 |
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Re: Murphy A855G- no sound.
Picture of the rear.
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21st Jun 2018, 6:35 pm | #59 |
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Re: Murphy A855G- no sound.
Picture of the wires exiting the windings.
It's not too clear but there are three single strands. Thanks again. |
21st Jun 2018, 7:09 pm | #60 |
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Re: Murphy A855G- no sound.
That transformer has had it.
I don't know about the cabinet area feeling too warm, but there must have been a stink and probably some smoke! Even if that transformer wasn't o/c on its primary (and it will be), with that amount of burning damage it would be too dangerous to use anyway. Looking back to the post #5 on page one of this thread, I think we can safely say that it was well established at that stage that the transformer was open circuit due to the OP saying that he'd run it for a couple of hours and there was no sound and no 'warming' but the deck was still working, as they're both fed from the same circuit. Before thinking about a replacement or rewound transformer, I think it would now be prudent to find out what caused it to burn out like that. One clue that the OP gave us was when I asked him about the indicator lamp. The lamp seems to run off its own winding on the transformer and the OP told us that it worked sometimes and that when he investigated the innards, that the wire fell off. Perhaps this wire had been off before and had been bodged back on by twisting the wires round the connector, causing a short - the OP will have to tell us, or perhaps there was a short circuit as the wire worked its way off? If that lamp circuit developed a short circuit, the record player would carry on working, possibly for several hours until the overload on the transformer became too much, causing it to finally burn out. On the other hand, there could be a fault in the rectifier, smoothing or amplifier, but the OP seems to indicate to us that the player was working fine for several hours before suddenly stopping with the hot area of the cabinet being noticed - back to that indicator lamp then. |