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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
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27th May 2017, 6:10 pm | #1 |
Retired Dormant Member
Join Date: Feb 2017
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Roberts R600 not working
Picked up this Roberts R600 which is a nice looking radio and my 1st venture away from Hacker's.....thought I would try something different.
Nice looking radio and the casing has cleaned up lovely but the internals are not working all all when you connect a battery.....completely dead with no sound or noises from the speaker. what would be the 1st things to check?.....I'm still new to this forum and are learning all the time from you fellow members so all help appreciated I've downloaded the schematics ready |
27th May 2017, 6:15 pm | #2 |
Octode
Join Date: Jan 2003
Location: Guildford, Surrey, UK.
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Re: Roberts R600 not working
Earphone jack, as there is no sound coming from the speaker. You could also measure the battery current to see if the on/off switch works.
Ron |
27th May 2017, 6:47 pm | #3 |
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Re: Roberts R600 not working
Can you tell me how to do that, I do have a multi meter, as I said I'm new to this and showing me a few basic steps will help....thanks
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27th May 2017, 7:00 pm | #4 |
Moderator
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Re: Roberts R600 not working
Use a meter on a current range to measure the current flowing out of the battery.
Spray some contact cleaner in the earphone socket and then push a plug in and out a few times. Unfortunately these radios are not a great choice for the inexperienced. They contain both AF11x and Lockfit transistors, both of which are prone to faults. These are contained within Mullard RF and IF modules which are difficult to remove. There are writeups of servicing these modules on the net if you google, but it's not for the faint hearted. |
27th May 2017, 7:19 pm | #5 | |
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Re: Roberts R600 not working
Set your meter to a current range and be sure to put the leads in the correct sockets. They're often not the same as those used for voltage and resistance measurements.
Connect the meter leads to the contacts of the OFF/ON switch. With the switch in the OFF position the meter will show how much current the set is drawing. Quote:
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Graham. Forum Moderator Reach for your meter before you reach for your soldering iron. |
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27th May 2017, 7:36 pm | #6 |
Pentode
Join Date: Oct 2008
Location: Downham Market, Norfolk, UK.
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Re: Roberts R600 not working
I recommend you have a look at Graham's excellent Youtube channel.
He has tackled several R600's and other Roberts sets. https://www.youtube.com/channel/UCDj...8Cjw/playlists
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Regards, John. |
27th May 2017, 7:38 pm | #7 | |
Dekatron
Join Date: May 2008
Location: Derby, UK.
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Re: Roberts R600 not working
Quote:
First test, meter on 20V DC (⎓) range, across C24 (Trader sheet) and close the power switch S16. You should see 9V. If not, set meter to 200mA DC, black probe to terminal of S16 that is connected to black battery lead, red probe to "circuit" terminal of S16 (so you are using the meter to bypass S16). If you now get life (and a reading of a few tens of mA) that suggests S16 could be faulty. If the set is still silent but some current is flowing (10mA or less), try temporarily connecting a speaker (just about any one will do) between C23 negative and battery negative. If this works, the fault must be with the earphone socket or the speaker.
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If I have seen further than others, it is because I was standing on a pile of failed experiments. |
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27th May 2017, 8:07 pm | #8 | |
No Longer a Member
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Re: Roberts R600 not working
Quote:
R600's can be pretty scary to work on but they do sound excellent when they're working properly. |
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27th May 2017, 8:47 pm | #9 |
Dekatron
Join Date: May 2008
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Re: Roberts R600 not working
I'll third that, just for his mellifluous voice
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If I have seen further than others, it is because I was standing on a pile of failed experiments. |
27th May 2017, 9:27 pm | #10 |
Hexode
Join Date: Dec 2013
Location: Torrington, Devon UK.
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Re: Roberts R600 not working
Well firstly thanks for all the kind plugs for my YouTube channel. I think Ron has probably hit the nail on the head with the headphone jack as if the module has packed up you will still get some sounds from the speaker. I have sacrificed a Roberts R600 so as I can test refurbished modules so if you need a hand with it then let me know. It will be fun.
Regards Graham |
28th May 2017, 11:33 am | #11 |
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Re: Roberts R600 not working
Thanks for all your comments and help.....this will give me plenty to go on and make a start and see what happens......also big thanks Graham with your You Tube channel.....have been watching your restoration on the R600......this is going to help me big time......if the AF117's have to be replaced can I use AF137's?
will keep you guys updated with progress.......really enjoying this |
28th May 2017, 11:44 am | #12 |
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Re: Roberts R600 not working
AF137s should work if you can find some, but they are very uncommon. The AF124-7 is the safest replacement and not difficult to find, though they have become pricey nowadays. There are lots of threads on AF11x replacement if you search the forum.
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28th May 2017, 11:58 am | #13 |
Rest in Peace
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Re: Roberts R600 not working
The Russian GT322 Transistors, usually available on eBay for around £1 each make good replacements for AF11x transistors. They have leads approx 25mm long, which makes them easier to fit than AF12x series devices.
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29th May 2017, 9:09 am | #14 | |
Hexode
Join Date: Dec 2013
Location: Torrington, Devon UK.
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Re: Roberts R600 not working
Quote:
Good luck Graham |
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29th May 2017, 9:33 am | #15 |
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Re: Roberts R600 not working
Thanks for that Graham....yes will purchase some AF125's, they are really cheap from www.buy-transistors.com at only £1.91 each so will buy a few as I have a couple of Hackers where they need replacing
Can you point me to the electrolytic capacitors, which ones they are? sorry a lot of these is new to me but I'm determined to get the radio working In fact just picked up a HMV battery radio for £0.92p, not sure if working but tuning dial is stiff just need to finish watching the rest of the Roberts R600 videos now many thanks....Stuart |
29th May 2017, 9:07 pm | #16 |
Nonode
Join Date: Mar 2013
Location: Leicester, UK
Posts: 2,535
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Re: Roberts R600 not working
If you want to try the Russian GT322's then I have some left over from a previous repair of an R200 so could send you a couple. Just PM me.
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30th May 2017, 9:18 pm | #17 |
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Re: Roberts R600 not working
The radio is working superbly on all three wavebands and boy is the volume loud.......I am so pleased to been able to fix this, well overjoyed.
Yes as a lot of you suspected it was the earphone socket, I de-soldered the connections, the red wire touched the casing and I got noise through the speaker....next the earphone socket was out and dismantled as Graham's YouTube vid, but this one is slightly different as picture shows, that fluff on the cocktail stick is what came out the inside, so cleaned all connections, recleaned the perspex face and touched up the back, sprayed contact cleaner in all the switches and pots, re-soldered the wires back, tried it out... Bingo!!!, working, no crackles, all crystal clear... cleaned casing up and it's all back together, well pleased Will post the final pictures later in the week I don't think any components want changing as it sounds so good A big thanks to all you guys for the comments and recommendations, and especially Graham's YouTube clips where I gained a lot of knowledge next on my list is a Robert's R300 Thanks again everyone, what a great forum |
30th May 2017, 9:33 pm | #18 |
Rest in Peace
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Re: Roberts R600 not working
That's my boy!
Well done, Stu. Most radios and televisions have their "stock faults", perhaps weak points in the original design, or common components that have aged badly. As you gain experience, you'll learn them, the same way that the old radio shop guys did. Cheers, Frank Last edited by frankmcvey; 30th May 2017 at 9:40 pm. |
31st May 2017, 8:30 am | #19 |
Hexode
Join Date: Dec 2013
Location: Torrington, Devon UK.
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Re: Roberts R600 not working
Well done Stuart. Sounds like you didn't have to delve into the module either which is a bonus. Probably on borrowed time though unless the module has been done in the past. I'm glad that my videos helped. I take the headphone sockets apart on all the top panel mounted ones and clean them as they have caused a couple of sets to fail. I do like the sound of these radios when they are sorted. On to the next one now then.
All the best Graham |
31st May 2017, 9:27 am | #20 |
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Re: Roberts R600 not working
As Graham says, the transistors will fail eventually, but it might be tomorrow or twenty years from now. At least you now know what's involved when the time comes, and can postpone the job until you have more experience.
The R300 does contain 3 AF117s too, but they are much easier to change if necessary, and a large number of replacements will work because of the relatively low frequencies involved. |