27th Mar 2017, 6:26 pm | #1 |
Retired Dormant Member
Join Date: Aug 2016
Location: Shrewsbury, Shropshire, UK.
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Decca TP85
Hi all
I recently picked up a Decca TP85 from a car boot sale along with a Tellux TLP5 record player. The Decca was sold as untested, i have tried a battery in it and it makes a faint noise. I have seen that this radio can take two batteries but in this one there is only 1 connection point. Question 1 Will it only work with 2 batteries? Question 2 Are any of the points on the back where i can connect it to the mains? I must also say I am not very technically minded so please go easy on all the technical jargon Thanks in advance |
27th Mar 2017, 6:49 pm | #2 |
Dekatron
Join Date: Jun 2015
Location: Biggin Hill, London, UK.
Posts: 5,213
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Re: Decca TP85
To answer question 2 :
No, unfortunately none of those sockets are for a mains adapter/power supply. From the left, the first 2 are aerial inputs (for AM and FM), the next is an output for an earphone, then an output for a tape recorder (to record the programme you are listening to) and finally an input from a record player pickup to listen to records using the radio's amplifier and speaker. |
27th Mar 2017, 6:49 pm | #3 |
Rest in Peace
Join Date: Apr 2011
Location: Matlock, Derbyshire, UK.
Posts: 1,378
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Re: Decca TP85
It looks as if it runs on a PP9 battery. Use a PP3 to test it. Make sure the polarity is correct.
I see no sign of a mains power supply. There may be input connections for an external 9V supply. |
27th Mar 2017, 6:59 pm | #4 |
Octode
Join Date: Dec 2010
Location: St Ives, Cambridgeshire, UK.
Posts: 1,180
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Re: Decca TP85
It's got AF114-6 transistors in there which is what's probably stopping it working on the receiving side. The proper battery fit is two PP9 in parallel.
Andrew
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27th Mar 2017, 7:08 pm | #5 |
Dekatron
Join Date: Nov 2009
Location: Lincolnshire, UK.
Posts: 5,000
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Re: Decca TP85
It's supposed to have two PP9 batteries run in parallel, but it will work with just one. As said, NO mains connection.
It has the AF117 (including 114-115 etc.) type transistors with the four leads. All of these may be faulty due to 'tin whiskering' shorting the internal junction to the screening can, which is the forth leg on what would normally be a three legged device. If the set doesn't work with a PP9 battery connected and you've cleaned the switches with 'Servisol 10', then you'll need to cut or unsolder all the 'screen' connections to those four legged transistors. The set will then normally work perfectly, but be aware that there is one transistor under the metal screening on the far left which is awkward to get to. |
27th Mar 2017, 8:18 pm | #6 |
Retired Dormant Member
Join Date: Aug 2016
Location: Shrewsbury, Shropshire, UK.
Posts: 24
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Re: Decca TP85
I have tried it with 1 PP9 battery and have got some noise coming from it, i can't see anywhere where i can add a second PP9.
Also when i connected the PP9 if i switch the polarity the noise gets louder? |
27th Mar 2017, 8:37 pm | #7 |
Dekatron
Join Date: Nov 2003
Location: Fakenham, Norfolk, UK.
Posts: 4,257
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Re: Decca TP85
There won't be any noticeable difference between operation with one PP9 in good condition and with two. Maybe someone just wanted the second connector for something else, I don't have a TP85 within reach but I expect the second should be wired directly to the existing one, positive to positive and negative to negative. Any sound you hear on reversing polarity on the other hand is likely to be the sound of components dying... best not to try that again.
Paul |
27th Mar 2017, 8:39 pm | #8 |
Dekatron
Join Date: Sep 2003
Location: Near Swindon, North Wiltshire, UK.
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Re: Decca TP85
As has already been said, there is no provision on the sockets at the rear of this radio to connect an external low voltage dc supply (instead of the internal PP9 battery).
As this radio has AF11x type transistors fitted, some (if not all) will be faulty and stop the radio from working (apart from making a plop or crackle at switch on and off). When restored, they work very well (I have one). As you are not technically minded and have tried the correct PP9 battery, you can do no more, other than have it restored/repaired by a technically competent person. This will not come cheap. Restorers that can do this work advertise their services here: http://www.vintage-radio.net/forum/f...play.php?f=146 You can also advertise for a repairer here:http://www.vintage-radio.net/forum/f...play.php?f=145 Last edited by dazzlevision; 27th Mar 2017 at 8:41 pm. Reason: Additional text. |