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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
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#1 |
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
Posts: 572
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Received this today complete with broken dial glass :' (Put a battery in it and got a loud crackle when I adjusted the volume control, but nothing else. So whipped the covers off it and tapped the dreaded AF117's transistors with a screwdriver and it burst into life. MW was working well but nothing on LW. It played for a short while but now it's stone dead, not a crackle. Nothing,
Voltage is reaching the on/off switch. Shorted transistor or capacitor? Cheers, Jay.
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#2 |
Banned
Join Date: Oct 2015
Location: Cornwall, UK.
Posts: 849
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Is that the right model number??
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#3 |
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
Posts: 572
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#4 |
Moderator
Join Date: Jun 2003
Location: Oxford, UK
Posts: 23,552
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Your description of the symptoms suggests the AF117s are knackered. All the usual advice applies. There may also be a problem with the MW/LW wavechange contacts, which usually need a good clean.
Has the volume control crackling stopped as well as everything else? |
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#5 | |
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
Posts: 572
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Cheers.
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#6 | |
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
Posts: 572
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Cheers
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#7 |
Moderator
Join Date: Jun 2003
Location: Oxford, UK
Posts: 23,552
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The OC82D is a pretty run of the mill transistor, and lots of types will replace it, though it does depend on the circuit. In a typical 2 transformer amp design just about any PNP device can be used, including silicon types. Ideal subs would be OC71, OC72, OC81D, OC81, AC126, AC128 but try whatever you have to hand.
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#8 | |
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
Posts: 572
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Cheers jay
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#9 |
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
Posts: 572
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Well i changed the audio driver for an ACY18 and could hear stations on MW albeit quiet. Tapped the mixer/osc and it burst into life, So gonna swap it out. Infact i might get shot of all the AF117s. Still nothing on LW. Probably a band switch issue.
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#10 |
Moderator
Join Date: Jun 2003
Location: Oxford, UK
Posts: 23,552
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The ACY18 should be fine, despite being intended as an industrial transistor.
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#11 | |
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
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Should i leave them or replace them to prevent future problems ? ![]()
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#12 |
Moderator
Join Date: Jun 2003
Location: Oxford, UK
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I would change them all while you have the radio dismantled. Do them one at a time. Any Ge transistor with an ft of 2MHz or better should be OK in a MW/LW radio, and Si types of the BC214/BC558/2N3906 class should be OK too if you have them.
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#13 | |
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
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Thanks for your input ![]() Cheers Jay.
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#14 |
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
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I have a load of unbranded capacitors i was thinking of using to recap the radio. The ESR on them is around 8 ohms. Is this considered high ?
Cheers Jay.
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#15 |
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
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Could anybody tell me if the contacts on this band switch should be on the outside or the inside, See pic below. And how do you dismantle it ? As in removing the metal part ?
[img]************************qBZL12r7/IMAG0309.jpg[/img]
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#16 |
Octode
Join Date: Dec 2012
Location: Bocking, near Braintree, Essex, UK.
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Hi Jay
I would suggest changing all of those horrible AF117 transistors to those Russian equivalents, and provided the IF's have not been twiddled then you should be OK, from what you say it burst into life when the AF117 transistors were tapped, this would then suggest the driver stage and output stage are OK, I would also check the printed circuit side for any dry joints and even minute breaks in those tracks. Ken |
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#17 | |
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
Posts: 572
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![]() Cheers Jay
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#18 |
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
Posts: 572
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Everything that could go wrong with this radio has gone wrong
![]() Now i have misaligned contacts on the band switch and the volume is lower than it should be, And to make things worse the dial cord came off ![]() But my first job is going to be fixing the band switch. Anybody know how these come apart and where the contacts are meant to be ? On the left of the switch the contacts are on the outside, (Sure thats were they're meant to be) On the right side they're on the inside.. See pic below
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Help!! I've been electrocuted by a glass thing that glows ![]() Last edited by Radio Scotland; 8th Apr 2021 at 7:46 pm. |
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#19 |
Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 12,068
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There should be contacts on the outside, in all the switches of a similar type that I've worked on the moving contacts wipe both sides of the fixed contacts.
Lawrence. |
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#20 | |
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
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Jay
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