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Old 7th Mar 2021, 9:52 pm   #1
BotleyJoe
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Default Dynatron Music Center - Help Please

Hello - I'm a new member looking for some help with a Dynatron music center please. I hope I'm posting in the right section of the Forum. This is it....
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The problem is that I have very little sound coming from one channel. It was OK on Friday and now the it is almost inaudible. This is the board for the side in question...
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I've been posting on Lenco Heaven and it was suggested that it was probably due to the capacitors failing but I should see if you guys could help. Unfortunately I have very little knowledge of electronics so I watched a few "how to" videos on YouTube and followed the instructions on how to check the capacitors with a multimeter. All the components seemed to pass the tests but given my lack of knowledge I may not have been doing the job correctly.

I've just fitted a very nice Lenco GL75 to the unit so I'd really like to get the thing working if I can. The problem is common to all the inputs (radio & deck).

All help and suggestions most welcome.

Many thanks in advance.
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Old 7th Mar 2021, 10:09 pm   #2
paulsherwin
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Default Re: Dynatron Music Center - Help Please

The most likely explanation is that you have some dirty switch or potentiometer contacts. This is unlikely to be a bad capacitor problem. Beware of hifi forums telling you to replace all the capacitors in equipment - this seems to be an article of faith in some quarters, but plastic film capacitors almost never fail, and even electrolytics are much more reliable than a lot of people think.
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Old 7th Mar 2021, 10:11 pm   #3
BotleyJoe
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Default Re: Dynatron Music Center - Help Please

Thank you. I have tried squirting contact cleaner into the sliders. It made a small difference initially but it didn't last. Should I have another go?
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Old 7th Mar 2021, 10:13 pm   #4
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Default Re: Dynatron Music Center - Help Please

You probably know already but please don’t play any records until the counterweight is replaced and set up on the end of the tone arm. It will “sag”, they all seem to because of the mounting method.

Peter
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Old 7th Mar 2021, 10:36 pm   #5
BotleyJoe
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Default Re: Dynatron Music Center - Help Please

Quote:
Originally Posted by Reelman View Post
You probably know already but please don’t play any records until the counterweight is replaced and set up on the end of the tone arm. It will “sag”, they all seem to because of the mounting method.

Peter
Thanks Peter but don't worry, that was just a quick spin to see if there was any difference to the sound on the phono input. There wasn't.
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Old 7th Mar 2021, 10:54 pm   #6
100series
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Default Re: Dynatron Music Center - Help Please

Hmmm.
These are top of the line Dynatrons and it seems immaculate inside and out.
I have 5. I paid very little for most of them and some were in very rough condition, I mean filthy with missing slider knobs and even with some of the sliders bent, none of the lights working and making no sound at all on radio or phono outputs. Ostensibly dead.
However .... every single one after a lot of cleaning, care, a little soldering and contact spray have opened their eyes and now work perfectly.
They are as tough as old boots despite appearing as temperamental as the thoroughbreds they are.
This is surprising as the fault affects all outputs.
My first suggestion is please select the radio output button and jam (gently) your finger so you are pressing the button in to its fullest extent. The selector buttons get really sticky and need a little "incentive" to do their job.
Do the same with the phono (obviously while playing a record). Just hold the button in.
The most likely culprit is the tape button as that overrides both the other inputs and if sticky can just affect one channel or both. This is the most likely.
Please try this and report back.
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Old 7th Mar 2021, 11:44 pm   #7
100series
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Default Re: Dynatron Music Center - Help Please

Try holding in the tape monitor button in the output choice buttons column. Hold it against the stops(but gently).
10 to one that is sticky and when playing up can block one or both channels for whatever output you are using.
If I am right you owe me a drink. A diet Coke please.
I tried answering earlier but Im new and it didn't get though. Ive got 5 of these beauties so have a little experience.
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Old 8th Mar 2021, 2:36 am   #8
jamesperrett
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Default Re: Dynatron Music Center - Help Please

As Reelman says, the counterweight and anti-skating weight are missing from your picture so you'll be ruining your stylus and your records by using it in that state.

The switches on these aren't great and cause quite a few problems so they would be the first thing to check. Have you tried exercising all the switches? Have you tried plugging in a pair of headphones? Do you get sound on both channels from the tape output?
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Old 8th Mar 2021, 11:00 am   #9
BotleyJoe
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Default Re: Dynatron Music Center - Help Please

Thank you all for your suggestions. I'll try them these this evening.

Quote:
Originally Posted by 100series View Post
Try holding in the tape monitor button in the output choice buttons column. Hold it against the stops(but gently).
10 to one that is sticky and when playing up can block one or both channels for whatever output you are using............
If it turns out to be that simple I'll owe you all a drink
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Old 8th Mar 2021, 12:40 pm   #10
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Default Re: Dynatron Music Center - Help Please

The slider controls did give problems in the 1970’s, I had to replace a few at that time. Plenty other possible causes though.
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Old 8th Mar 2021, 2:45 pm   #11
Edward Huggins
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Default Re: Dynatron Music Center - Help Please

Quote:
Originally Posted by jamesperrett View Post
As Reelman says, the counterweight and anti-skating weight are missing from your picture so you'll be ruining your stylus and your records by using it in that state.

?

OUCH - I'm surprised that the deck is able to play records at all like that!
Is the OP missing the two weights or just has he just not fitted them as yet?
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Last edited by Cobaltblue; 8th Mar 2021 at 4:13 pm. Reason: Fixed quote
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Old 8th Mar 2021, 4:13 pm   #12
BotleyJoe
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Default Re: Dynatron Music Center - Help Please

Quote:
Originally Posted by 100series View Post
Try holding in the tape monitor button in the output choice buttons column. Hold it against the stops(but gently).
10 to one that is sticky and when playing up can block one or both channels for whatever output you are using.......If I am right you owe me a drink. A diet Coke please..
I owe you a very large diet Coke! It worked! Even through a pair of rubbish speakers the sound is excellent. So I can now crack on and fit the Lenco deck (with weights & anti-skate! ). The deck is pretty much as new having never been used and was still in its plastic wrapping and in the original box.

Thank you to all those who suggested concentrating on the switches.

As mentioned above, this unit is in really lovely condition condition* so to finish it off it would be nice to find a replacement knob for the "Treble" slider.
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If anyone has one I be very happy to swap it for some beer vouchers.

Many thanks again to everyone.

*unfortunately there is no dust cover but that's now really the only negative.
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Old 8th Mar 2021, 10:54 pm   #13
BotleyJoe
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Default Re: Dynatron Music Center - Help Please

I've now "lost" VHF reception completely. LW & MW are still there. Is this another temperamental button issue? Also, and very annoyingly, this piece of plastic has fallen across the wavelength selection window.
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I've managed to get it to drop back into place but it seems to be held in position by the bulb. Is there any way of making this part more secure?

Is this https://www.ebay.co.uk/itm/2-x-6-Vol...4AAOSwjpRap8Nf the bulb I need?

Sorry for all the questions but this seems to be a classic case of "one step forward two steps back"
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Old 8th Mar 2021, 11:33 pm   #14
100series
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Default Re: Dynatron Music Center - Help Please

I am very pleased it was the right suggestion.

Can I recommend some Dynatron LS 3038's as speakers? You will not believe how good these sound if the cones are in good order (and they do not have legs).

You have a wonderful machine there and everyone who sees and hears it will be impressed. If you need anymore help please post and I will help if I can.
I am new and have read the rules but if I see a dust cover I will let you know but prefer coke tokens to beer tokens. Those knobs are generic and used on many ITT/Marconi/Pye music centres so should be easy to find.
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Old 8th Mar 2021, 11:35 pm   #15
BotleyJoe
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Default Re: Dynatron Music Center - Help Please

Quote:
Originally Posted by 100series View Post
....... If you need anymore help please post and I will help if I can. ......
Many thanks again. Yes I do need more help. Can you have a look at my last post please?
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Old 8th Mar 2021, 11:54 pm   #16
100series
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Default Re: Dynatron Music Center - Help Please

The bulbs work. Just pull out the clear plastic holder with the bulb in, unscrew the bulb, scrub the screw bit with a pan scourer and screw it back in. In fact it will light up if you just jiggle it in situ. Its just fallen asleep. Wake it up.

I dont know what piece of plastic you are referring to. Do what seems logical to secure it.

Yes its a temperamental button issue. All the buttons need to be used. After decades of not being used they have corroded up. If you sat in a chair for twenty years your knees would be very stiff and if you tried to stand up you wouldn't.
You would need to get an attractive nurse to repeatedly bend and flex your legs for a few sessions before you can get up and walk unaided. You are the nurse so (gently) repeatedly push the buttons for as long as it takes to get them to work as they should. They WILL work but you got to put the time in. Watch TV while you do it as you got a lot of buttons and a lot of button pushing to do. BE GENTLE. They can break. Spray contact cleaner into the aperture hole. The crack is narrow but accurate pointing will get the jet into the button assembly if it has a spout attached to the nozzle.
Good luck.
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Old 9th Mar 2021, 12:07 am   #17
BotleyJoe
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Default Re: Dynatron Music Center - Help Please

Quote:
Originally Posted by 100series View Post
The bulbs work. Just pull out the clear plastic holder with the bulb in, unscrew the bulb, scrub the screw bit with a pan scourer and screw it back in. In fact it will light up if you just jiggle it in situ. Its just fallen asleep. Wake it up.....
Not this one!
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It has about as much chance of waking up as an Egyptian mummy
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Old 10th Mar 2021, 12:14 am   #18
100series
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Default Re: Dynatron Music Center - Help Please

Haha. Looks like my crystal ball.
Sorry about that.
I have had so many Dynatrons that at first were dark and even the tiny bulbs for the stereo signal worked as they were only asleep. I didn't realise it was busted.
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Old 10th Mar 2021, 12:21 am   #19
BotleyJoe
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Default Re: Dynatron Music Center - Help Please

Still no VHF but I have managed to remove the facia and fix the little metal bar back in place.

It is great when things are so well built in the first place as it makes dismantling and reassembly so much easier. Someone must have screwed this unit together by hand.
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Old 10th Mar 2021, 12:46 am   #20
100series
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Default Re: Dynatron Music Center - Help Please

Even with my defunct crystal ball I can 99% assure you that if the VHF once worked it will work again. but you must, repeat must, have a good arial connected to the VHF arial socket at the back.
Without one you get nothing but hiss. If it isn't even hissing at you I am still fairly confident it is just asleep and needs a good shake, metaphorically speaking.

Aren't they great? I find myself staring at plug and play 40 years before MS came up with the term. So easy to swap out for a different Turntable. I love them.
Seriously, the speakers are the real surprise. They can look as attractive as granny's false teeth but once you hear them all that is forgotten. And for peanuts.
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