Identification Transistor Dynatron Record Player (Carnival) - UK Vintage Radio Repair and Restoration Discussion Forum

uk_snowman · 25th Apr 2017, 6:35 pm

Can any one identify this Transistor Dynatron Record Player
it has a Garrard AT6 Turntable as im after a wiring diagram for it

the volume on this player is very low and this component looks to be in poor shape (picture uploaded)

Cobaltblue · 25th Apr 2017, 6:41 pm

The component in poor shape looks like a thermistor probably used to compensate the output transistors bias with change of temperature.

Could be a VA1077 from the remaining colours.

Not well up on record players perhaps a Cordova GR14?

Cheers

Mike T

Records · 25th Apr 2017, 6:42 pm

Dynatron Carnival 1963/64

uk_snowman · 25th Apr 2017, 7:03 pm

Thanks for the replys

Ive found a data sheet for the Dynatron Carnival but it does not tell me any values for the Thermistor, just wondering how would i test it and if needed what would i replace it with?

ms660 · 25th Apr 2017, 7:08 pm

Almost certainly a VA1077, data in this link:

http://www.electrojumble.org/DATA/Mu...rom_VA1053.pdf

Lawrence.

Edward Huggins · 25th Apr 2017, 7:30 pm

You can download the wiring (circuit) diagram from this site. See the top RHS of this screen.

uk_snowman · 25th Apr 2017, 8:51 pm

I now have the wiring diagram thanks.
I'm just wondering what would be a suitable replacement.
Could i use a 33ohm resistor as a temporary replacement?

Techman · 25th Apr 2017, 11:52 pm

Although that 'component' looks to be in poor shape, do you actually know that it is causing your low volume?

Have you checked the output from the cartridge?

Have you fed a signal into the amplifier input to test whether the low volume is due to the amplifier and not the cartridge?

What about doing the 'buzz' test on the cartridge connectors with the volume turned full on - what were the results?

uk_snowman · 26th Apr 2017, 12:05 am

Yes i have used my old trusted mp3 player connected to the amp input and i can only just hear it play when the amp is on full volume

Techman · 26th Apr 2017, 12:11 am

Ah, that's ok then.

You've got the data on the thermistor and know what resistance it should be at around room temperature so you can test it. If faulty then I would probably experiment with a resistor.

Nuvistor · 26th Apr 2017, 8:22 am

You have proved the amp is faulty, have you done any testing to try and find which stage is causing the fault? It may well be the thermistor but some standard fault finding techniques may prove the fault elsewhere .
Frank

uk_snowman · 2nd May 2017, 11:03 am

Just replaced the Thermistor with a 33ohm resistor and it's now working.
My next question is it safe to leave the resistor in place or should I get a new Thermistor if so what type should I replace it with?

'LIVEWIRE?' · 2nd May 2017, 11:09 am

Ideally that 33 ohm resistor should be replaced with a VA1053, VA 1077 or equivalent thermistor (are these still available, btw?), as these vary in resistance with temperature, as you no doubt know. Their purpose is to stabilse the output stage under changing temperatures. A glance at the data sheets in that link will show that the resistance of an NTC thermistor falls with increasing temperature, in the case of the VA1077, from approx 33 ohms @ 25 deg. C to under 1 ohm @ 100deg. C., and rises again as the device cools down.

uk_snowman · 2nd May 2017, 2:29 pm

Ok would this be a suitable replacement from RS

http://uk.rs-online.com/web/p/thermistors/2161438/

uk_snowman · 9th May 2017, 8:07 pm

I fitted the EPCOS 33Ω 3100mW NTC Thermistor from RS and its now working properly

25th Apr 2017, 6:35 pm	#1
uk_snowman Hexode Join Date: Jun 2013 Location: Norwich, Norfolk, UK. Posts: 281	Identification Transistor Dynatron Record Player (Carnival) Can any one identify this Transistor Dynatron Record Player it has a Garrard AT6 Turntable as im after a wiring diagram for it the volume on this player is very low and this component looks to be in poor shape (picture uploaded) Attached Thumbnails __________________ Now where did I put that part again!!!

25th Apr 2017, 6:41 pm	#2
Cobaltblue Moderator Join Date: Dec 2010 Location: Exeter, Devon and Poole, Dorset UK. Posts: 6,865	Re: Identification Transistor Dynatron Record Player The component in poor shape looks like a thermistor probably used to compensate the output transistors bias with change of temperature. Could be a VA1077 from the remaining colours. Not well up on record players perhaps a Cordova GR14? Cheers Mike T __________________ Invisible airwaves crackle with life or at least they used to Mike T BVWS member. www.cossor.co.uk Last edited by Cobaltblue; 25th Apr 2017 at 6:53 pm. Reason: added possible thermistor type.

25th Apr 2017, 6:42 pm	#3
Records Hexode Join Date: Jul 2011 Location: Harwich, Essex, UK. Posts: 429	Re: Identification Transistor Dynatron Record Player Dynatron Carnival 1963/64

25th Apr 2017, 7:03 pm	#4
uk_snowman Hexode Join Date: Jun 2013 Location: Norwich, Norfolk, UK. Posts: 281	Re: Identification Transistor Dynatron Record Player Thanks for the replys Ive found a data sheet for the Dynatron Carnival but it does not tell me any values for the Thermistor, just wondering how would i test it and if needed what would i replace it with? __________________ Now where did I put that part again!!!

25th Apr 2017, 7:08 pm	#5
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: Identification Transistor Dynatron Record Player Almost certainly a VA1077, data in this link: http://www.electrojumble.org/DATA/Mu...rom_VA1053.pdf Lawrence.

25th Apr 2017, 7:30 pm	#6
Edward Huggins Dekatron Join Date: Sep 2015 Location: Southwold, Suffolk, UK. Posts: 8,328	Re: Identification Transistor Dynatron Record Player You can download the wiring (circuit) diagram from this site. See the top RHS of this screen. __________________ Edward.

25th Apr 2017, 8:51 pm	#7
uk_snowman Hexode Join Date: Jun 2013 Location: Norwich, Norfolk, UK. Posts: 281	Re: Identification Transistor Dynatron Record Player I now have the wiring diagram thanks. I'm just wondering what would be a suitable replacement. Could i use a 33ohm resistor as a temporary replacement? __________________ Now where did I put that part again!!!

25th Apr 2017, 11:52 pm	#8
Techman Dekatron Join Date: Nov 2009 Location: Lincolnshire, UK. Posts: 5,000	Re: Identification Transistor Dynatron Record Player Although that 'component' looks to be in poor shape, do you actually know that it is causing your low volume? Have you checked the output from the cartridge? Have you fed a signal into the amplifier input to test whether the low volume is due to the amplifier and not the cartridge? What about doing the 'buzz' test on the cartridge connectors with the volume turned full on - what were the results?

26th Apr 2017, 12:05 am	#9
uk_snowman Hexode Join Date: Jun 2013 Location: Norwich, Norfolk, UK. Posts: 281	Re: Identification Transistor Dynatron Record Player Yes i have used my old trusted mp3 player connected to the amp input and i can only just hear it play when the amp is on full volume __________________ Now where did I put that part again!!!

26th Apr 2017, 12:11 am	#10
Techman Dekatron Join Date: Nov 2009 Location: Lincolnshire, UK. Posts: 5,000	Re: Identification Transistor Dynatron Record Player Ah, that's ok then. You've got the data on the thermistor and know what resistance it should be at around room temperature so you can test it. If faulty then I would probably experiment with a resistor.

26th Apr 2017, 8:22 am	#11
Nuvistor Dekatron Join Date: Aug 2013 Location: Wigan, Greater Manchester, UK. Posts: 9,433	Re: Identification Transistor Dynatron Record Player You have proved the amp is faulty, have you done any testing to try and find which stage is causing the fault? It may well be the thermistor but some standard fault finding techniques may prove the fault elsewhere . Frank

2nd May 2017, 11:03 am	#12
uk_snowman Hexode Join Date: Jun 2013 Location: Norwich, Norfolk, UK. Posts: 281	Re: Identification Transistor Dynatron Record Player Just replaced the Thermistor with a 33ohm resistor and it's now working. My next question is it safe to leave the resistor in place or should I get a new Thermistor if so what type should I replace it with? __________________ Now where did I put that part again!!!

2nd May 2017, 11:09 am	#13
'LIVEWIRE?' Rest in Peace Join Date: Mar 2006 Location: N.W. Oxfordshire(Chipping Norton) Posts: 7,306	Re: Identification Transistor Dynatron Record Player Ideally that 33 ohm resistor should be replaced with a VA1053, VA 1077 or equivalent thermistor (are these still available, btw?), as these vary in resistance with temperature, as you no doubt know. Their purpose is to stabilse the output stage under changing temperatures. A glance at the data sheets in that link will show that the resistance of an NTC thermistor falls with increasing temperature, in the case of the VA1077, from approx 33 ohms @ 25 deg. C to under 1 ohm @ 100deg. C., and rises again as the device cools down. Last edited by 'LIVEWIRE?'; 2nd May 2017 at 11:18 am.

2nd May 2017, 2:29 pm	#14
uk_snowman Hexode Join Date: Jun 2013 Location: Norwich, Norfolk, UK. Posts: 281	Re: Identification Transistor Dynatron Record Player (Carnival) Ok would this be a suitable replacement from RS http://uk.rs-online.com/web/p/thermistors/2161438/ __________________ Now where did I put that part again!!!

9th May 2017, 8:07 pm	#15
uk_snowman Hexode Join Date: Jun 2013 Location: Norwich, Norfolk, UK. Posts: 281	Re: Identification Transistor Dynatron Record Player (Carnival) I fitted the EPCOS 33Ω 3100mW NTC Thermistor from RS and its now working properly __________________ Now where did I put that part again!!!