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Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment.

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Old 4th Dec 2019, 5:21 am   #1
Exasperant
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Default Tonesta Conquest No Audio - Loose Wire

Hi

I'm trying to teach myself how to repair interesting things (and make really uninteresting unfunny videos whilst doing so - That's less of a try, more of a sad reflection). I picked up a "Tonesta Conquet automatic" that was sold as "Turns, but no sound, loose wire".

Having opened it up, I can see a PCB with no valves, and two what I assume to be transistors for the audio.

I can also see two white wires coming from the transformer. One goes to the negative leg of a radial capacitor, the other goes... Into mid air.

I'm guessing the lack of audio is due to lack of power going into the PCB, but I can't tell for certain where the wire should go. There is a diode on the corner of the PCB that seems to have no tracks, wires, etc feeding into it.

PCB is marked "LE-2"

I'm tempted to solder the hanging wire to the otherwise pointless diode, but am worried I could blow something up. Has anyone got a schematic, or maybe photo of this board all wired up?

Thanks!
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Old 4th Dec 2019, 11:34 am   #2
paulsherwin
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Default Re: Tonesta Conquest No Audio - Loose Wire

I don't know this player, but you are right not to poke around randomly with no idea what you're doing. You may cause damage, or even start a fire or electrocute yourself. You will need to teach yourself some electronics basics - voltages, currents, different components, how power supplies and amplifiers work. This isn't something you can do on a whim, and only you can know if you are sufficiently interested to bother.

Sorry
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Old 4th Dec 2019, 3:53 pm   #3
julie_m
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Default Re: Tonesta Conquest No Audio - Loose Wire

Two transistors doesn't sound like enough for a record player, but perhaps there are others hiding?

I think we need to see some pictures of the internals of the record player!

It can almost certainly be got working .....
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Old 4th Dec 2019, 8:46 pm   #4
Edward Huggins
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Default Re: Tonesta Conquest No Audio - Loose Wire

Tonesta was a second brand of Dansette. This may be a Tonesta version of the "Conquest" Mk2 perhaps? If so it will have 2 valves. Maybe the OP will see the vacant B9A valve holders.
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Old 5th Dec 2019, 3:50 pm   #5
Exasperant
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Default Re: Tonesta Conquest No Audio - Loose Wire

I'll try to take photos later, but there's a lack of valves or anywhere to put them.

The previous owner seemed pretty honest when he said he'd opened it up for a look inside, and a wire fell off. Didn't seem the sort to sneak out valves for nefarious purposes.

Reading through this forum I saw similar-ish looking transistor setups, but nothing that could point me to where this wire is meant to be. My first guess is that diode that's sat only one side connected to anything, but because that's a guess I don't want to just solder it up, and then release exploderous magic smoke...
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Old 6th Dec 2019, 11:56 pm   #6
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Default Re: Tonesta Conquest No Audio - Loose Wire

Finally managed to grab some pics.

The loose whire disappears off, alongside the white wire soldered to the (neg, I think) side of the capacitor, to the transformer.

I might be being blind, but I don't see any valves, or places valves should be!

I'm figuring the red, white, and blue wires are feeding transistors, although I base this purely on photos I've found on this forum.

One pic shows the top view of the diode I mentioned, the other corner closeup is the underside - It seems as though only one side of that diode is in the circuit, which is why I'm wondering if that's where the loose wire should go. But this is based on intuition, not knowledge, the thinking being the diode surely must do something, and would be useful for turning AC into DC.
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Old 7th Dec 2019, 1:15 am   #7
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Default Re: Tonesta Conquest No Audio - Loose Wire

Definitely no valves, just four transistors. As far as I can see, your intuition is correct. The loose wire should go to that diode, which is the LT rectifier, and normal service should be restored.
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