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Success Stories If you have successfully repaired or restored a piece of equipment, why not write up what you did and post details here. Particularly if it was interesting, unusual or challenging. PLEASE DO NOT POST REQUESTS FOR HELP HERE! |
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18th Jan 2006, 10:50 am | #1 |
Octode
Join Date: Oct 2005
Location: Wimborne, Dorset, UK.
Posts: 1,407
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DAC90A Lives again!
Hi all,
Two years ago I purchased a DAC90A from the NVCF at the bargain price of £35...yes £35. It had a label saying "not working". I decided to get it. On handing over the cash the trader asked for another £10! I said to him it's marked up at £35. He thought for some bizzare reason he marked it up at £45. anyway I have only just got around to looking at the set and on opening it up I was pleasantly surprised to see that someone with good skills had already fitted a black 3 core mains pvc lead and disconnected the mains input socket. Also it had a full complement of new caps (the little yellow ones from RS, the MKT series) I could see the person who had done this had good soldering skills and everything was neatly done, well this filled me with confidence and I decided to power up through my variac. Powering up brought forward no problems and after a few minutes crackles could be heard when adjusting the volume but no signals could be heard I had a quick look round and dicovered that the UCH42 had no heater glow....HMmm, short circuit heater I thought so I whipped the valve out and couldn't believe my luck for this valve was not a UCH42 but an ECH42, now full of excitement I rushed up stairs to my valve stock and rumaged round and found a UCH42. Well what more is there to say, I popped the new valve in and switched on. After about 45 seconds I was rewarded with more than ample output and the little beast was pulling in plenty of stations on both MW and LW very clearly so I decided realignment was not necsasary. Must be my easiest restoration ever! All the best Lee
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Lee |
18th Jan 2006, 11:32 am | #2 |
Retired Dormant Member
Join Date: Dec 2003
Location: North London, UK.
Posts: 6,168
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Re: DAC90A Lives again!
Excellent buy! I'd like to know where the earth core of the mains lead was connected.
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18th Jan 2006, 12:07 pm | #3 |
Moderator
Join Date: Jun 2003
Location: Oxford, UK
Posts: 27,936
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Re: DAC90A Lives again!
I know some people like to connect the metal speaker grille to an earth wire.
Paul |
18th Jan 2006, 12:30 pm | #4 |
Octode
Join Date: Oct 2005
Location: Wimborne, Dorset, UK.
Posts: 1,407
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Re: DAC90A Lives again!
Crikey Moses!
I've just twigged. The Earth I remember seeing it connected to chassis! Obviously if I used an rcd when I first powered up (like I should) then I would have been aware of this dangorous mod. I can't believe I didn't twig, i know only to well it has neutral connected to chassis!! What a complete Thanks for pointing that out, must change that tonight!! Regards Lee
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Lee |
18th Jan 2006, 12:36 pm | #5 |
Moderator
Join Date: Jun 2003
Location: Oxford, UK
Posts: 27,936
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Re: DAC90A Lives again!
I wouldn't call it dangerous... The worst that would happen would be a blown plug fuse or tripped breaker in the consumer unit.
Not exactly wise though It's surprising that someone would be competent to recap a radio and still do something like this Best regards, Paul |
18th Jan 2006, 1:32 pm | #6 |
Dekatron
Join Date: Jan 2004
Location: Newcastle upon Tyne, Tyne & Wear, UK.
Posts: 8,194
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Re: DAC90A Lives again!
Hi Lee it might also be worth checking that the output valve base has no connections to the IC/NC pins (4&5 I think) as these can cause problems if certain types of valve are fitted where there is an internal connection to that pin. It's a simple matter to lift the components in the air and leave them there.
Ed |
18th Jan 2006, 3:27 pm | #7 |
Octode
Join Date: Oct 2005
Location: Wimborne, Dorset, UK.
Posts: 1,407
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Re: DAC90A Lives again!
Hi Ed,
Thanks for that tip, I will also check this when I rewire the earth to the speaker grill tonight. Regards Lee
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Lee |
18th Jan 2006, 6:25 pm | #8 |
Octode
Join Date: Dec 2005
Location: Near Stowmarket, Suffolk, UK.
Posts: 1,962
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Re: DAC90A Lives again!
Sounds like a nice restoration! Although I had a DAC90A for Christmas I know my parents did not spend less than £15 on it fully restored!
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19th Jan 2006, 12:50 am | #9 |
Heptode
Join Date: Jul 2003
Location: North Walsham, Norfolk, UK.
Posts: 516
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Re: DAC90A Lives again!
Arr just a thought have thay done the schasis isolation trick i remember reading this somewhere ? Danny
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19th Jan 2006, 2:09 pm | #10 |
Retired Dormant Member
Join Date: Feb 2005
Location: Monmouthshire,on South Wales border
Posts: 85
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Re: DAC90A Lives again!
That is horrendus,I would have sorted out the mains lead first!To use 3 core lead on most radio sets is just not on,they are not classed as an appliance to be pat tested anyway.I have a few sets now that supposed to have been "restored" by a professional these have 3 core leads which are causing hum problems,these will be fitted with 2 core lead as intended.It scares me to see what these anti- restorers get up to.
As regards the DAC90A, I assume the safety connector has been removed also,what amazes me that so few people have accidents by all these dangerous mods that people are doing. Only class 1 appliances require an earth,does not apply to vintage domestic radio. Where the case is not wood or bakelite,the only sets which are earthed are metal cased communication receivers. |
21st Jan 2006, 1:06 pm | #11 |
Retired Dormant Member
Join Date: Nov 2005
Location: CHELMSFORD, ESSEX,UK
Posts: 26
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Re: DAC90A Lives again!
Danny may be thinking of the article entitled "Safety First and a leaky DAC" by GaryTempest in the BVWS Bulletin for the Summer 2002,Vol 27 No.2.
Regards, Don |