Pandu Rajan
Member
Yes I have the circuit diagram of this set.
Regards
P.Rajan
Dear Mr. Rajesh
Thanks for your comments.
Do you still have the Philips valve radio with you?
Regards
P.Rajan
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valve Radios and valves
- Thread starter Pandu Rajan
- Start date
Yes I have the circuit diagram of this set.
Regards
P.Rajan
Dear Mr. Rajesh
Thanks for your comments.
Do you still have the Philips valve radio with you?
Regards
P.Rajan
Actually it is a Murphy Radio. Apologies if I've stated it as Philips elsewhere. Yes Rajanji I still have it at my Mom's place. She would be maha thrilled just to see it play again. I wish I can restore it.
Pandu Rajan
Member
Before making my previous post, I had called my sister to check precisely that but unfortunately, the attic is too high for her reach. :sad:
Will get the info by this weekend (hopefully)
One thing I knew is my Dad telling me that it can be incorporated in a Radiogram which he never did. During my college days, I remember connecting the audio out of our Bush Tape deck into the aux in because it sounded far superior than the sound from the bush speaker.:licklips:
Pandu Rajan
Member
Before making my previous post, I had called my sister to check precisely that but unfortunately, the attic is too high for her reach. :sad:
Will get the info by this weekend (hopefully)
One thing I knew is my Dad telling me that it can be incorporated in a Radiogram which he never did. During my college days, I remember connecting the audio out of our Bush Tape deck into the aux in because it sounded far superior than the sound from the bush speaker.:licklips:
Dear Mr. Rajesh
About one year back I had restored one Philips radios set B6CA58A which was fitted in a radio gram for a person living in Chennai. He had brought only the Chasis part to Bangalore. It took me nearly 20 days to bring it to its original condition. I also repaired one of the speakers which was badly damaged. To restore a Philips set the speakers are a very important part and only the original speakers give a satisfactory performance. Normally I am unable to put in more than an hour a day for my hobby work and that is why it takes more time.
Regards
P.Rajan
Great to know. I'd certainly require your expertise in getting the Radio repaired. Will be in touch.
vmscbe1974
Active Member
Dear Mr. Rajan ji
People like you keep alive the joy of young enthusiast like us.. It was a pleasure talking to you over the phone and i have the radiogram you have posted in the picture.
Regards
Srinivasan.M
People like you keep alive the joy of young enthusiast like us.. It was a pleasure talking to you over the phone and i have the radiogram you have posted in the picture.
Regards
Srinivasan.M
Dear Srinivasan,
Can you please post a photo of your radiogram?
Thanking you,
pksnathan
I happened to visit Hyderabad a while ago and took the Radio down and clicked some pics. Here they are:
reubensm
Well-Known Member
Its in splendid condition, the tubes look in great nick. The line resistor (for the tube filaments) to the right, just over the AC mains cable entry point suggests that your radio is what was called an AC/DC radio. If it is, then be careful with the polarity of the AC mains plug or the chassis will become live (aerial socket as well). If you have the radio earthed and then reverse the AC mains plug, your room's CB on your home's CB panel, is likelly to turn off.
Nice to see the vintage speakers, vintage wiring with tag boards and of course, the infamous gram socket.
Pandu Rajan
Member
Dear Mr. Rajesh
I will check up If I have the service manual for this set or not?
Regards
P.Rajan
I will check up If I have the service manual for this set or not?
Regards
P.Rajan
Spot on Reuben. I had learned it the hard way while fiddling with it for routing our Bush Tape recorder's output to be heard through the radio.
Why infamous?
I lack expertise to restore it myself. I would be obliged if you could help me in getting it restored. I can take care of the wood work though.
reubensm
Well-Known Member
Why infamous?
In the early days, record players used to come with metallic tonearms. When connected to an AC/DC radio with the mains polarity reversed, the user would get the jolt of his life when he touched the tonearm. Many record enthusiasts including my father, his friends, and even I have experienced it as a kid. :lol:
Interestingly, most of these AC/DC radios came with 2-way plugs instead of the required 3-way. Using a 3-pin mains plug could have mitigated this risk, however again, given the socio-economic circumstances prevalent in India, back in the day, its is unlikely that most households had 3-pin mains sockets with earthing, anyways.
Gram or PU sockets were staple on tube radios back in the day especially in India. The AC tube radios with the standard auto-transformer were considered safe.
Interestingly many people bought AC/DC radios as (1) they were less expensive (one could by an upward model for the price of a mid-level AC radio) and (2) people thought that they would run on both AC and DC
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Pandu Rajan
Member
Dear Mr. Rajesh
I have the service sheets for the Murphy radio set TUO 777. It is a AC/DC set. The valve line up is UCH81,UF89,UBC81,UL84,UM84 and UY85. It is a 4-band set. There was a AC version set also and the model no was TAO 777. Since it is an AC/DC Murphy set I do not have the spares. Even the U-series valves are not available with me because I never worked on these sets. Moreover AC/DC sets are dangerous to work. One single mistake of connecting the plug in the reverse way and one could get electrocuted. ALL the filaments of the valves including the dial lamps and the voltage dropping resistor are in series and in total becomes the 220V. Normally when ever one used to work on these sets they used to have an Isolation Transformer to have necessary protection.
Regards
P.Rajan
I have the service sheets for the Murphy radio set TUO 777. It is a AC/DC set. The valve line up is UCH81,UF89,UBC81,UL84,UM84 and UY85. It is a 4-band set. There was a AC version set also and the model no was TAO 777. Since it is an AC/DC Murphy set I do not have the spares. Even the U-series valves are not available with me because I never worked on these sets. Moreover AC/DC sets are dangerous to work. One single mistake of connecting the plug in the reverse way and one could get electrocuted. ALL the filaments of the valves including the dial lamps and the voltage dropping resistor are in series and in total becomes the 220V. Normally when ever one used to work on these sets they used to have an Isolation Transformer to have necessary protection.
Regards
P.Rajan
reubensm
Well-Known Member
Have a dumb question, when i was in school, i spent quite a lot of time looking through a longish book called Practical Radio Circuits which had radio circuits of all the known brands (Indian). I noticed that the circuitry was the AC and AC/DC sets was basically the same with a few changes to filtering. I was quite small back then so maybe I missed something but hypothetically, one can actually switch from U-series to E-series with a change in Power supply and filament wiring (parallel for 6.3 volt). Is this practically possible?
reubensm
Well-Known Member
Imagine, the AC/DC radio going stone dead because of a fused dial lamp...in AC radios the dial would just go dark but the radio would continue to sing.
Pandu Rajan
Member
Dear Sir
It is not very simple to change the radio set from a AC/DC to pure AC.
1. Main transformer is required in the AC radio.
2. All the filaments are in parallel and therefore wiring will have to be changed.
3. All the valves will have to be replaced.
4. The most important part is the output transformer. The load impedance for the valve EL84 is different than UL84. So the output transformer will have to be replaced to match EL84 which now days is not available.
5. Another important point are the anode and screen grid voltages. In the AC/DC set these voltages are lower as compared to the AC set for all the valves. So the anode and screen grid resistances will also have to be changed to correct value for the E series valves.
6. The cathode biasing is also different.
7. Some of the condensers may also have to be replaced.
8. The dial lamp will also have to be changed. Now days it is very difficult to get 6.3V, 0.3A bulbs. Only 6V bulb is available which gets fused quickly.
So you can see a lot of changes will have to be done to do this modification.
Regards
P.Rajan
It is not very simple to change the radio set from a AC/DC to pure AC.
1. Main transformer is required in the AC radio.
2. All the filaments are in parallel and therefore wiring will have to be changed.
3. All the valves will have to be replaced.
4. The most important part is the output transformer. The load impedance for the valve EL84 is different than UL84. So the output transformer will have to be replaced to match EL84 which now days is not available.
5. Another important point are the anode and screen grid voltages. In the AC/DC set these voltages are lower as compared to the AC set for all the valves. So the anode and screen grid resistances will also have to be changed to correct value for the E series valves.
6. The cathode biasing is also different.
7. Some of the condensers may also have to be replaced.
8. The dial lamp will also have to be changed. Now days it is very difficult to get 6.3V, 0.3A bulbs. Only 6V bulb is available which gets fused quickly.
So you can see a lot of changes will have to be done to do this modification.
Regards
P.Rajan
Uh oh you mean you won't help me in getting it restored!:sad:
Pandu Rajan
Member
Dear Mr. Rajesh
O.K. If you bring it to Bangalore I will give a try. In case the IF transformer or the coils are defective then it will become difficult. This can only be ascertained after checking.
Regards
P.Rajan
O.K. If you bring it to Bangalore I will give a try. In case the IF transformer or the coils are defective then it will become difficult. This can only be ascertained after checking.
Regards
P.Rajan
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