Thanks for yet another interesting and informative video on transistor radio repair. I'm really enjoying your channel. It's good to see Roberts, Hacker and other quality transistor sets finally being appreciated.
+Harry F Thanks for the kind comment Harry. There is such a variety of these sets that as a collector its hard to say no to even the later sets. There's very little information on the internet about them as well so hopefully my endeavours will help keep some of these out of landfill or possibly save an expensive repair bill. Thanks Graham
Thanks for this. I'm repairing an RP28 for a friend so this is really useful. To say that these are badly made would be to underrate the skill of Chinese bodgers. How many times do these things have to fail because of reverse polarity before they put in a diode. They don't even have to have a voltage drop, but I expect they are too busy having tea to find that out.
you all probably dont care but does anybody know a method to get back into an instagram account..? I was stupid lost the login password. I would appreciate any help you can offer me.
@Benton Clayton Thanks so much for your reply. I found the site on google and Im in the hacking process now. Looks like it's gonna take a while so I will get back to you later with my results.
I just bought two Motorola's tube portable radio ,if I new how to send you a picture I would love to see if you ever worked on that type of radio both 1950 era radios,both work ,which is one of the reason ,I bought and they are very nice radios,Someday I hopeing I can afford a Roberts because of your videos kinda falling in love with that brand ,and I would love someday to buy one of your ,but shipping so pricey.
Hi Ron. My email is Graham@radiocruncher.com if you want to send pictures over. I have worked on a lot of pocket radios from that era. Roberts are available but you will have to search hard over there to find one
Excellent job. I have had three RP28's with blown speakers... swapped the speakers out in each and all good. I never used to check speakers first, but now I do on the RP28's. I used to trace the boards looking for faults that weren't there... Any idea what would cause this Graham?
All came from different places at different times over the last few years. The one I finished yesterday had been worked on previously, it was a real bind getting the radio away from the case as it had been glued in (I think with epoxy!). It came in with 'no power', and initial thoughts were the ic's or bad caps, but no, a simple speaker swap was all was required - again!
Very nice repair ,makes me glad I work on tube radios ,I am going to work on 1960 era.micky mouse radio in the future that solid state ,it works perfect I just want to replace some 50 year old caps ,Just hope I don't screw it up .
I have one of these in executive wine red, in fact the first radio I bought when I started fixing'em up. Good thing it worked as I knew practically nothing about how they worked then! The thing keeps gradually losing tuning so it's consigned to the pile of shame at the moment. Are you going to put diodes in the incoming supply leads to stop polarity reversal? Just thinking about your recent Roberts repairs and the RP28 has nowhere near the quality of earlier sets. That said, Roberts are still in business, Hacker et al are not. Regards _ Andrew
+Andrewausfa diodes would be a good idea Andrew. It would save someone in the future having the same problem. I am just tidying up the case at the moment so would be a good time to do it before I put it all back together. I've heard that these can drift a bit but not really heard what causes it. I agree that these newer radios are nowhere near the same build quality as the older ones. I wonder when they did the switch as I assume these are now made in China or at least the boards. Don't worry though as I have a huge pile of old Roberts, Hackers, Dynatron, Bush, Perdio, Cossor etc. still to come. I'm going to be tackling a few valve radios as well soon. Thanks again for the comment. Graham
I too was going to suggest using diodes...hopefully that will save the IC's (cheaper anyway). I'm starting to like these and the Hackers....do you know if any were targeted towards the US markets? Maybe under another brand? Might be interested in picking one up. ~Jack, VEG
Jack, I think Roberts probably would have exported but don't think they used a different name. Hacker as far as I know didnt. I have plenty of RP28's here if you fancy one. Just drop me an email or message. Diodes will be going in any that I sell on as I dont want them coming back damaged. I do now have some power suppplies that are the correct polarity though. Thanks for watching. All the best Graham
Would be interested on knowing what their counterpart was! I will keep that in mind Graham, I'm not a real big fan on this particular radio as it appears it is only tuned via the presets(?), however I do like the fact it has them as well as that cool popup window! I would want something easier to play with! :) Thank you! ~Jack, VEG
Jack, there are so many to consider! If you want something that sounds good, is reasonably priced but still can be repaired relatively easily then its got to be either a Roberts R600 or for the best sounding radio that Roberts made it's the R707. For Hacker its probably got to be a Hunter RP38a, although Sovereign's and Heralds are very good as well. Regards Graham
May I ask where you got your TA8117Ns from? And also the 78L05s. I know I can get 50 of those from China for 99p but I'm doing this for a friend. For the main chip I am a bit leery about getting a fake from China but Farnell don't stock it.
I bought some from a seller on eBay back in 2016. He’s still selling them here rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F323490100920. If you want one I might be able do it depending on how many I have left
@@Radiocruncher Thanks for that link. I was a little wary of getting specialist chips from China. I know from audio that there are a lot of fakes out there so it's good to know these aren't among them. Incidentally, Iq (from your video) is the quiescent current, which is essentially what the chip needs to draw in order to keep the transistors switched on. It's a more useful number in amplifiers, where it is what sets the 'bias' to give a smooth transition between positive going output and negative going output. In this regulator it is just telling you what the overhead is with no load; but in fact isn't even that useful, because the biggest loss is the drop from 9V to 5V, at whatever current the circuit is drawing. That DCA75 looks like a nice little device.
Christian Thomas your welcome. Thanks for the info on the quiescent current. I hadn’t worked on this type of radio before so it was a bit of a mystery. If you want a TA8117N a bit faster then let me know and I will do you one for the same price. All the Peak testers are really useful and I use them on a daily basis so well worth buying. Regards Graham
Hi Marc. You will need to remove the chassis from the case 1st. Then unscrew the grubscrews, remove the knobs and Perspex dial cover. The pointer is a friction fit. I use forceps but a screwdriver inserted in the slot of the red pointer to spread it a little will enable it to be taken off
Yes the 5 volt one...Im watching your video as we speak...and I love all of them...Have you ever seen or worked on a Sony CRF-160? Im getting one in by Friday, I hope...good day..
Hi Kenny. I have just had a look at my parts bin and it looks like it was a L78L05. That Sony looks really nice. I have seen them for sale but haven't got one. It's probably like a lot of the other Japanese multi band radios of the 60's which are tricky to work on. Good luck, thanks for watching and for the kind comment. Graham
Radiocruncher Thanks Graham! I have been away on a little break. I have it ready to go just going to write your address on a label and send it tomorrow. Thanks, speak soon.
I did a lot of trouble shooting on this radio and narrowed it down to one of the IC’s. I initially thought it was the audio IC but it turned out to be the rf IC. There is no schematic or service info for this set so I was going blind and hoped that finding no output voltage from the regulator was an easy fix but I assume that the polarity had been reversed taking out the IC as well. Since doing this radio I have done a few more similar ones with the same IC damaged so it seems this is the one that goes in most cases. Thanks for watching, Graham
Thanks for yet another interesting and informative video on transistor radio repair. I'm really enjoying your channel. It's good to see Roberts, Hacker and other quality transistor sets finally being appreciated.
+Harry F Thanks for the kind comment Harry. There is such a variety of these sets that as a collector its hard to say no to even the later sets. There's very little information on the internet about them as well so hopefully my endeavours will help keep some of these out of landfill or possibly save an expensive repair bill. Thanks Graham
Thanks for this. I'm repairing an RP28 for a friend so this is really useful. To say that these are badly made would be to underrate the skill of Chinese bodgers. How many times do these things have to fail because of reverse polarity before they put in a diode. They don't even have to have a voltage drop, but I expect they are too busy having tea to find that out.
Thanks Christian. Not Roberts finest hour! A diode would have been an easy addition to the circuit. Penny pinching
you all probably dont care but does anybody know a method to get back into an instagram account..?
I was stupid lost the login password. I would appreciate any help you can offer me.
@Anders Isaac Instablaster :)
@Benton Clayton Thanks so much for your reply. I found the site on google and Im in the hacking process now.
Looks like it's gonna take a while so I will get back to you later with my results.
@Benton Clayton It worked and I finally got access to my account again. I'm so happy!
Thanks so much, you saved my account :D
I just bought two Motorola's tube portable radio ,if I new how to send you a picture I would love to see if you ever worked on that type of radio both 1950 era radios,both work ,which is one of the reason ,I bought and they are very nice radios,Someday I hopeing I can afford a Roberts because of your videos kinda falling in love with that brand ,and I would love someday to buy one of your ,but shipping so pricey.
Hi Ron. My email is Graham@radiocruncher.com if you want to send pictures over. I have worked on a lot of pocket radios from that era. Roberts are available but you will have to search hard over there to find one
Excellent job. I have had three RP28's with blown speakers... swapped the speakers out in each and all good. I never used to check speakers first, but now I do on the RP28's. I used to trace the boards looking for faults that weren't there... Any idea what would cause this Graham?
That’s a strange fault. Did these radios come from the same person? Maybe someone has put power into the headphone socket
All came from different places at different times over the last few years. The one I finished yesterday had been worked on previously, it was a real bind getting the radio away from the case as it had been glued in (I think with epoxy!). It came in with 'no power', and initial thoughts were the ic's or bad caps, but no, a simple speaker swap was all was required - again!
Great work! a diode for polarity protection is well worth adding to it.
Thanks Mohider. I have started adding a Schottky diode in the power supply on recent repairs
Great troubleshooting video thanks for sharing
Very nice repair ,makes me glad I work on tube radios ,I am going to work on 1960 era.micky mouse radio in the future that solid state ,it works perfect I just want to replace some 50 year old caps ,Just hope I don't screw it up .
Excellent tutorial for fault finding.
Thanks Ray. It was a learning curve for me as well. Thanks for watching, Graham
I have one of these in executive wine red, in fact the first radio I bought when I started fixing'em up. Good thing it worked as I knew practically nothing about how they worked then! The thing keeps gradually losing tuning so it's consigned to the pile of shame at the moment. Are you going to put diodes in the incoming supply leads to stop polarity reversal? Just thinking about your recent Roberts repairs and the RP28 has nowhere near the quality of earlier sets. That said, Roberts are still in business, Hacker et al are not.
Regards _ Andrew
+Andrewausfa diodes would be a good idea Andrew. It would save someone in the future having the same problem. I am just tidying up the case at the moment so would be a good time to do it before I put it all back together. I've heard that these can drift a bit but not really heard what causes it. I agree that these newer radios are nowhere near the same build quality as the older ones. I wonder when they did the switch as I assume these are now made in China or at least the boards. Don't worry though as I have a huge pile of old Roberts, Hackers, Dynatron, Bush, Perdio, Cossor etc. still to come. I'm going to be tackling a few valve radios as well soon. Thanks again for the comment. Graham
I too was going to suggest using diodes...hopefully that will save the IC's (cheaper anyway). I'm starting to like these and the Hackers....do you know if any were targeted towards the US markets? Maybe under another brand? Might be interested in picking one up. ~Jack, VEG
Jack, I think Roberts probably would have exported but don't think they used a different name. Hacker as far as I know didnt. I have plenty of RP28's here if you fancy one. Just drop me an email or message. Diodes will be going in any that I sell on as I dont want them coming back damaged. I do now have some power suppplies that are the correct polarity though. Thanks for watching. All the best Graham
Would be interested on knowing what their counterpart was! I will keep that in mind Graham, I'm not a real big fan on this particular radio as it appears it is only tuned via the presets(?), however I do like the fact it has them as well as that cool popup window! I would want something easier to play with! :) Thank you! ~Jack, VEG
Jack, there are so many to consider! If you want something that sounds good, is reasonably priced but still can be repaired relatively easily then its got to be either a Roberts R600 or for the best sounding radio that Roberts made it's the R707. For Hacker its probably got to be a Hunter RP38a, although Sovereign's and Heralds are very good as well. Regards Graham
May I ask where you got your TA8117Ns from? And also the 78L05s. I know I can get 50 of those from China for 99p but I'm doing this for a friend. For the main chip I am a bit leery about getting a fake from China but Farnell don't stock it.
I bought some from a seller on eBay back in 2016. He’s still selling them here rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F323490100920. If you want one I might be able do it depending on how many I have left
@@Radiocruncher Thanks for that link. I was a little wary of getting specialist chips from China. I know from audio that there are a lot of fakes out there so it's good to know these aren't among them. Incidentally, Iq (from your video) is the quiescent current, which is essentially what the chip needs to draw in order to keep the transistors switched on. It's a more useful number in amplifiers, where it is what sets the 'bias' to give a smooth transition between positive going output and negative going output. In this regulator it is just telling you what the overhead is with no load; but in fact isn't even that useful, because the biggest loss is the drop from 9V to 5V, at whatever current the circuit is drawing. That DCA75 looks like a nice little device.
Christian Thomas your welcome. Thanks for the info on the quiescent current. I hadn’t worked on this type of radio before so it was a bit of a mystery. If you want a TA8117N a bit faster then let me know and I will do you one for the same price. All the Peak testers are really useful and I use them on a daily basis so well worth buying. Regards Graham
@@Radiocruncher I missed this kind offer, which I would very much like to take up. I wonder if I can PM you on UA-cam?
@@Radiocruncher I sent you an email on your business address, listed here. Was wondering if you got it?
Proves that people should be more aware about using any 9v adaptor , there are all marked with the polarity symbol .....
Hello!
On the RT1 you have in the backgroud (I think it's RT1)..
Ho do you remove the red arrow from the middle button (channel selector)?
Hi Marc. You will need to remove the chassis from the case 1st. Then unscrew the grubscrews, remove the knobs and Perspex dial cover. The pointer is a friction fit. I use forceps but a screwdriver inserted in the slot of the red pointer to spread it a little will enable it to be taken off
Thanks. Now I get it :)
What was that part number u replaced.?? something like 431.
It was a TA8117A unless you mean the 5v regulator
Yes the 5 volt one...Im watching your video as we speak...and I love all of them...Have you ever seen or worked on a Sony CRF-160? Im getting one in by Friday, I hope...good day..
Hi Kenny. I have just had a look at my parts bin and it looks like it was a L78L05. That Sony looks really nice. I have seen them for sale but haven't got one. It's probably like a lot of the other Japanese multi band radios of the 60's which are tricky to work on. Good luck, thanks for watching and for the kind comment. Graham
Can you not print the end cap?
Hi. I did try drawing it but it’s a complex shape. I still haven’t mastered the design software yet. Thanks for watching
Can you show how to fix a roberts R 9962
Hi Harvey. I do not have a Roberts R9962. Whats wrong with it?
Radiocruncher i accidently blew it up with a laptob charger
Laptop chargers are usually around 24v so you will have damaged the regulator section for sure but hopefully it didn’t get that far into the radio
Radiocruncher thanks :)
Was that a Toshiba TDA1083 IC?
The main ic is a TA8117N. Thanks for watching
👏👏👏👏👏👏
Thanks Attila glad you liked it. I did a similar one live last week
"Nope still nothing" hate it when that happens.
I got there in the end Robin. Thanks for watching
Hi Graham can you send me your details again please. I can't find the one you sent. Thanks mate.
Hi Lee. I was wondering where the Sony was. I have emailed you my details again. Regards Graham
Radiocruncher Sorry for the delay I will send it tomorrow via royal mail. Thanks again mate.
Radiocruncher Thanks Graham! I have been away on a little break. I have it ready to go just going to write your address on a label and send it tomorrow. Thanks, speak soon.
No worries Lee. Hope you had a nice break. I look forward to it arriving. All the best Graham
Went don't you troubleshooting the radio instead of Easter egging parts.
I did a lot of trouble shooting on this radio and narrowed it down to one of the IC’s. I initially thought it was the audio IC but it turned out to be the rf IC. There is no schematic or service info for this set so I was going blind and hoped that finding no output voltage from the regulator was an easy fix but I assume that the polarity had been reversed taking out the IC as well. Since doing this radio I have done a few more similar ones with the same IC damaged so it seems this is the one that goes in most cases. Thanks for watching, Graham
why bother????
It saved it from going in landfill. I recently sold the radio as well so all turned out well. Thanks for watching