Roberts R600 not working - UK Vintage Radio Repair and Restoration Discussion Forum

stuboy57 · 27th May 2017, 6:10 pm

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

ronbryan · 27th May 2017, 6:15 pm

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

stuboy57 · 27th May 2017, 6:47 pm

Quote:

Originally Posted by ronbryan

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

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

paulsherwin · 27th May 2017, 7:00 pm

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.

Station X · 27th May 2017, 7:19 pm

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:

Originally Posted by stuboy57

Quote:

Originally Posted by ronbryan

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

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

nebogipfel · 27th May 2017, 7:36 pm

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

julie_m · 27th May 2017, 7:38 pm

Quote:

Originally Posted by stuboy57

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?

Total silence is the best kind of fault, to be honest -- it usually means that the underlying problem is simple, such as no power getting through to the circuit or no signal getting to the speaker.

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.

canonman75 · 27th May 2017, 8:07 pm

Quote:

Originally Posted by nebogipfel

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

I'll second that

R600's can be pretty scary to work on but they do sound excellent when they're working properly.

julie_m · 27th May 2017, 8:47 pm

I'll third that, just for his mellifluous voice

Radiocruncher · 27th May 2017, 9:27 pm

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

stuboy57 · 28th May 2017, 11:33 am

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

paulsherwin · 28th May 2017, 11:44 am

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.

'LIVEWIRE?' · 28th May 2017, 11:58 am

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.

Radiocruncher · 29th May 2017, 9:09 am

Quote:

Originally Posted by stuboy57

......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

Thanks I'm glad it's helping. As it's the module, I would go with what Paul suggests and use the AF12x series. The AF125 is a good choice and are available at a sensible price from this seller http://pages.ebay.com/link/?nav=item...d=251921696821. You will need 3. Don't forget to replace the electrolytic capacitors as well.

Good luck

Graham

stuboy57 · 29th May 2017, 9:33 am

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

WaveyDipole · 29th May 2017, 9:07 pm

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.

stuboy57 · 30th May 2017, 9:18 pm

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

frankmcvey · 30th May 2017, 9:33 pm

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

Radiocruncher · 31st May 2017, 8:30 am

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

paulsherwin · 31st May 2017, 9:27 am

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.

27th May 2017, 6:10 pm	#1
stuboy57 Retired Dormant Member Join Date: Feb 2017 Location: Peterborough, Cambridgeshire, UK. Posts: 86	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 Attached Thumbnails

27th May 2017, 6:15 pm	#2
ronbryan Octode Join Date: Jan 2003 Location: Guildford, Surrey, UK. Posts: 1,960	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, 7:00 pm	#4
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,947	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, 7:36 pm	#6
nebogipfel Pentode Join Date: Oct 2008 Location: Downham Market, Norfolk, UK. Posts: 143	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 __________________ Regards, John.

27th May 2017, 8:47 pm	#9
julie_m Dekatron Join Date: May 2008 Location: Derby, UK. Posts: 7,735	Re: Roberts R600 not working I'll third that, just for his mellifluous voice __________________ 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
Radiocruncher Hexode Join Date: Dec 2013 Location: Torrington, Devon UK. Posts: 446	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
stuboy57 Retired Dormant Member Join Date: Feb 2017 Location: Peterborough, Cambridgeshire, UK. Posts: 86	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
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,947	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.

28th May 2017, 11:58 am	#13
'LIVEWIRE?' Rest in Peace Join Date: Mar 2006 Location: N.W. Oxfordshire(Chipping Norton) Posts: 7,306	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.

29th May 2017, 9:33 am	#15
stuboy57 Retired Dormant Member Join Date: Feb 2017 Location: Peterborough, Cambridgeshire, UK. Posts: 86	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
WaveyDipole Nonode Join Date: Mar 2013 Location: Leicester, UK Posts: 2,535	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.

30th May 2017, 9:18 pm	#17
stuboy57 Retired Dormant Member Join Date: Feb 2017 Location: Peterborough, Cambridgeshire, UK. Posts: 86	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 Attached Thumbnails

30th May 2017, 9:33 pm	#18
frankmcvey Rest in Peace Join Date: Jan 2015 Location: Cottesmore, East Midlands, UK. Posts: 858	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
Radiocruncher Hexode Join Date: Dec 2013 Location: Torrington, Devon UK. Posts: 446	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
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,947	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.