Premier Radio - UK Vintage Radio Repair and Restoration Discussion Forum

Trev757 · 1st Sep 2007, 1:44 pm

Hi all

I have been sent a small cream coloured bakellite radio for repair. It is simply marked "Premier Radio" on the dial, which is to the right hand side with 3 knobs below and the speaker to the left. It is a medium and long wave receiver. From the outside it looks identical to the Pilot Little Maestro of 1940. (I believe these cabinets were quite popular with other manufacturers for kit sets - see later).

This was originally being "repaired" by someone else (oh dear) and he asked the customer if he could obtain some parts for it. The customer contacted me and sent me a resistor, small electrolytic (almost certainly the audio o/p valve cathode decoupling cap) and another very sad Hunts brown wax paper type. I sent replacements, but advised him that there would certainly be other parts (especially more Hunts caps) that would need replacing.

The outcome is that the guy didn't deliver and the customer has now sent it to me to do the work. I was dreading taking the back off, but although some tinkering has clearly taken place, it doesn't look too horrendous.

The thing is, I now need to identify the model and get a circuit for it. Page 178 of "Radio Radio" shows an identical set, but states that this is an ac/dc TRF 3 valve + rec kit set. The set I have is ac/dc, but is clearly a superhet, with 4 valves and a pair of metal rectifiers.

Any help with identification and some service data would be very much appreciated.

Many tahnks

Trev

Steve_P · 1st Sep 2007, 2:05 pm

Get a valve data book, and look up the valves, and post the valves on here. If you have the valve data, you can probably trace the circuit through if needed.

You don't always need a circuit!!

Cheers,

Steve P

Trev757 · 1st Sep 2007, 2:16 pm

Yes I know I don't need a circuit and I've been doing this business long enough now to know my way around a classic superhet design blindfolded (like when I see a few 1 meg resistors joined together, I've probably found the AGC line). I do need to account for any more subtely used components though, that may be missing from the chassis due to the previous repairer. I'm just trying to make life a bit easier!

Sideband · 1st Sep 2007, 9:39 pm

I've got one of these kit sets but mine is AC only with a small heater transformer fitted. uses a standard superhet line-up with octal valves. Circuits are not very easy to find. Mine is based on the Repanco SH4. I doubt that they were published generally and were probably included with the original kit. Premier also tended to use whatever valves were available at the lowest possible price so it's even possible that two apparently identical kits may have had different valves.

There are some threads on Premier radio's in these forums so you could try doing a search. However you may have to resort to tracing out the circuit yourself.

Rich.

Trev757 · 2nd Sep 2007, 3:16 pm

Hi Rich

It sounds as if your set is very similar to mine. The strange thing with this one is the power supply. The mains lead is missing, therefore, on the mains switch (single pole) there is a tag with nothing connected to it. The other tag goes straight to chassis, therebye suggesting an ac/dc set. However, there is a transformer which clearly has HT, heater and pilot lamp windings, but I can't see any connections to a primary winding whatsoever! There are a couple of wires coming from the transformer soldered directly to it's frame, but I assume these are the other sides of the windings mentioned above (one wire looks of the heavier guage you would expect from a heater winding). My next step will be to remove the transformer and get all the grease and muck off it to have a closer look at what is going on. By the way, does your set have a couple of metal rectifiers fitted at the top right hand corner of the chassis as you look in from the back?

Being a kit set, I agree that a circuit would not have been generally published in ERT or similar for this set (anyone know different?). As regards components, I guess these sets would have originated from surplus component suppliers (a la Lisle Street, London) and the kits would therefore have been put together from whatever component "job lots" they had in at the time. The set I have includes capacitors by Hunts as well as a number of types from American to east European manufacturers. The valves are different manufacturers too; 6K8GT and 6K7GT are both "Tung-Sol" types; the 6Q7G is made by "Yale" and the VT501 is a UK military type bearing the crow's foot.

An interesting set indeed.

Any more discussion on these sets is welcome. Restoring kit sets is a new one on me

Trev

Trev757 · 2nd Sep 2007, 3:48 pm

Ok, I've just had a look at other threads on Premier Radio and things start to make sense now. I hadn't twigged that they derived the HT by directly rectifying the mains. Hence my assumption that the wire going from the transformer to the rectifier was a secondary. It is actually the mains input to the transformer (for the heaters/lamp) and the rectifier.

Definite modification required here I feel! No way will I return it to the customer without the chassis being earthed to ther mains. ....now where can i find a small HT transformer?.....

Trev

Brian R Pateman · 2nd Sep 2007, 4:36 pm

Quote:

Originally Posted by Trev757

Restoring kit sets is a new one on me

Trev

At least you can't be accused of non authentic repairs!

Regards,

Trev757 · 2nd Sep 2007, 8:48 pm

Hi Brian

You are absolutely right. I could fit any brand of contemporary component and no one could argue! Now where did I put those Outer Mongolian resistors.......?

Trev

Sideband · 2nd Sep 2007, 9:24 pm

Quote:

Originally Posted by Trev757

Hi Rich

It sounds as if your set is very similar to mine. By the way, does your set have a couple of metal rectifiers fitted at the top right hand corner of the chassis as you look in from the back?

Yes it does...or rather did!

The original rectifier was hoplessly low so I replaced it with a couple of series-connected BY126's and a 500 ohm limiter. I chose 500 ohms because it brought the HT down to about 220 volts on the anode of the 6V6 which seemed about right. Unfortunately in the absence of a proper circuit, the HT is unknown so a bit of 'educated quesswork' was required.

Quote:

Originally Posted by Trev757

Ok, I've just had a look at other threads on Premier Radio and things start to make sense now. I hadn't twigged that they derived the HT by directly rectifying the mains. Hence my assumption that the wire going from the transformer to the rectifier was a secondary. It is actually the mains input to the transformer (for the heaters/lamp) and the rectifier.

Yup...same as mine. Just a simple heater transformer so the mains is rectified directly. I've left mine as it is except that the single pole switch is rewired to switch the live rather than neutral side of the mains. It's only me using it anyway and all the screws are well insulated.

Rich.

PS. If you click on my website below, you can read my account of the repair.

Trev757 · 2nd Sep 2007, 10:24 pm

Hi Rich

Yes, from my experience of metal rectifiers, I won't even be bothering to try the set with them in. I will replace them with semiconductors and a surge limiting resistor as you have done by default. I will go for an HT of around 250V, which should be fine.

I did look at yours and other previous threads and the links and pictures associated with them. This will be a great help once i have gone round and made all the usual capacitor replacements, changed the rectifier etc and am ready to think about switching on.

The valves in mine test out ok except for the VT501, where the envelope is loose in it's holder and has to be wiggled about to get any results on the valve tester - the heaters are certainly intermittent. I might try unsoldering the wires from the pins, removing it from it's base and see if anything can be done to cure the intermittent connections and then re-cement the glass back into the base. I will probably then be able to test it, but find it's low emission or got an internal fault anyway!

I too would stick with the current power supply circuit if It was my own set. As you say, it is pretty well insulated and, ensuring that the live wasn't connected to chassis, should minimise any dangers. However, I wouldn't risk returning it to a customer without any isolation and a mains earth fitted.

Thanks for all the assistance so far.

Trev

Neil Purling · 2nd Sep 2007, 11:18 pm

From your point of view it has to be said that the cost of the work in getting the set into a safe-ish working condition may exceed whatever the customer may view as being reasonable.
This would be escecially true if you wanted to incorporate a transformer with a HT winding as well as a heater supply. I used a transformer from a tape deck.
I dont know what the performance is going to be like. If the thing has no RF amplifier it may be very mediocre. How many IF cans are there?
If you cannot find a VT501 beam tetrode then using another valve such as a EL32 or a 6V6 may be necessary with such re-working of the output stage as necessary. At least the rest of the valve lineup contains no surprise for you. I imagine there were simply so many VT501's around because nobody else thought they would be any use except in a transmitter.

1st Sep 2007, 1:44 pm	#1
Trev757 Banned Join Date: Dec 2004 Location: Bristol, UK. Posts: 218	Premier Radio Hi all I have been sent a small cream coloured bakellite radio for repair. It is simply marked "Premier Radio" on the dial, which is to the right hand side with 3 knobs below and the speaker to the left. It is a medium and long wave receiver. From the outside it looks identical to the Pilot Little Maestro of 1940. (I believe these cabinets were quite popular with other manufacturers for kit sets - see later). This was originally being "repaired" by someone else (oh dear) and he asked the customer if he could obtain some parts for it. The customer contacted me and sent me a resistor, small electrolytic (almost certainly the audio o/p valve cathode decoupling cap) and another very sad Hunts brown wax paper type. I sent replacements, but advised him that there would certainly be other parts (especially more Hunts caps) that would need replacing. The outcome is that the guy didn't deliver and the customer has now sent it to me to do the work. I was dreading taking the back off, but although some tinkering has clearly taken place, it doesn't look too horrendous. The thing is, I now need to identify the model and get a circuit for it. Page 178 of "Radio Radio" shows an identical set, but states that this is an ac/dc TRF 3 valve + rec kit set. The set I have is ac/dc, but is clearly a superhet, with 4 valves and a pair of metal rectifiers. Any help with identification and some service data would be very much appreciated. Many tahnks Trev

1st Sep 2007, 2:05 pm	#2
Steve_P Dekatron Join Date: Sep 2003 Location: Bolton, Greater Manchester, UK. Posts: 6,644	Re: Premier Radio Get a valve data book, and look up the valves, and post the valves on here. If you have the valve data, you can probably trace the circuit through if needed. You don't always need a circuit!! Cheers, Steve P __________________ If we've always had it, why is the Car Boot open? You're not sneaking another Old TV in are you...?

1st Sep 2007, 2:16 pm	#3
Trev757 Banned Join Date: Dec 2004 Location: Bristol, UK. Posts: 218	Re: Premier Radio Yes I know I don't need a circuit and I've been doing this business long enough now to know my way around a classic superhet design blindfolded (like when I see a few 1 meg resistors joined together, I've probably found the AGC line). I do need to account for any more subtely used components though, that may be missing from the chassis due to the previous repairer. I'm just trying to make life a bit easier!

1st Sep 2007, 9:39 pm	#4
Sideband Dekatron Join Date: Oct 2003 Location: Croydon, Surrey, UK. Posts: 7,572	Re: Premier Radio I've got one of these kit sets but mine is AC only with a small heater transformer fitted. uses a standard superhet line-up with octal valves. Circuits are not very easy to find. Mine is based on the Repanco SH4. I doubt that they were published generally and were probably included with the original kit. Premier also tended to use whatever valves were available at the lowest possible price so it's even possible that two apparently identical kits may have had different valves. There are some threads on Premier radio's in these forums so you could try doing a search. However you may have to resort to tracing out the circuit yourself. Rich. __________________ There are lots of brilliant keyboard players and then there is Rick Wakeman..... Last edited by Sideband; 1st Sep 2007 at 9:46 pm.

2nd Sep 2007, 3:16 pm	#5
Trev757 Banned Join Date: Dec 2004 Location: Bristol, UK. Posts: 218	Re: Premier Radio Hi Rich It sounds as if your set is very similar to mine. The strange thing with this one is the power supply. The mains lead is missing, therefore, on the mains switch (single pole) there is a tag with nothing connected to it. The other tag goes straight to chassis, therebye suggesting an ac/dc set. However, there is a transformer which clearly has HT, heater and pilot lamp windings, but I can't see any connections to a primary winding whatsoever! There are a couple of wires coming from the transformer soldered directly to it's frame, but I assume these are the other sides of the windings mentioned above (one wire looks of the heavier guage you would expect from a heater winding). My next step will be to remove the transformer and get all the grease and muck off it to have a closer look at what is going on. By the way, does your set have a couple of metal rectifiers fitted at the top right hand corner of the chassis as you look in from the back? Being a kit set, I agree that a circuit would not have been generally published in ERT or similar for this set (anyone know different?). As regards components, I guess these sets would have originated from surplus component suppliers (a la Lisle Street, London) and the kits would therefore have been put together from whatever component "job lots" they had in at the time. The set I have includes capacitors by Hunts as well as a number of types from American to east European manufacturers. The valves are different manufacturers too; 6K8GT and 6K7GT are both "Tung-Sol" types; the 6Q7G is made by "Yale" and the VT501 is a UK military type bearing the crow's foot. An interesting set indeed. Any more discussion on these sets is welcome. Restoring kit sets is a new one on me Trev

2nd Sep 2007, 3:48 pm	#6
Trev757 Banned Join Date: Dec 2004 Location: Bristol, UK. Posts: 218	Re: Premier Radio Ok, I've just had a look at other threads on Premier Radio and things start to make sense now. I hadn't twigged that they derived the HT by directly rectifying the mains. Hence my assumption that the wire going from the transformer to the rectifier was a secondary. It is actually the mains input to the transformer (for the heaters/lamp) and the rectifier. Definite modification required here I feel! No way will I return it to the customer without the chassis being earthed to ther mains. ....now where can i find a small HT transformer?..... Trev

2nd Sep 2007, 8:48 pm	#8
Trev757 Banned Join Date: Dec 2004 Location: Bristol, UK. Posts: 218	Re: Premier Radio Hi Brian You are absolutely right. I could fit any brand of contemporary component and no one could argue! Now where did I put those Outer Mongolian resistors.......? Trev

2nd Sep 2007, 10:24 pm	#10
Trev757 Banned Join Date: Dec 2004 Location: Bristol, UK. Posts: 218	Re: Premier Radio Hi Rich Yes, from my experience of metal rectifiers, I won't even be bothering to try the set with them in. I will replace them with semiconductors and a surge limiting resistor as you have done by default. I will go for an HT of around 250V, which should be fine. I did look at yours and other previous threads and the links and pictures associated with them. This will be a great help once i have gone round and made all the usual capacitor replacements, changed the rectifier etc and am ready to think about switching on. The valves in mine test out ok except for the VT501, where the envelope is loose in it's holder and has to be wiggled about to get any results on the valve tester - the heaters are certainly intermittent. I might try unsoldering the wires from the pins, removing it from it's base and see if anything can be done to cure the intermittent connections and then re-cement the glass back into the base. I will probably then be able to test it, but find it's low emission or got an internal fault anyway! I too would stick with the current power supply circuit if It was my own set. As you say, it is pretty well insulated and, ensuring that the live wasn't connected to chassis, should minimise any dangers. However, I wouldn't risk returning it to a customer without any isolation and a mains earth fitted. Thanks for all the assistance so far. Trev

2nd Sep 2007, 11:18 pm	#11
Neil Purling Nonode Join Date: Jul 2005 Location: Hull, East Yorkshire, UK. Posts: 2,087	Re: Premier Radio From your point of view it has to be said that the cost of the work in getting the set into a safe-ish working condition may exceed whatever the customer may view as being reasonable. This would be escecially true if you wanted to incorporate a transformer with a HT winding as well as a heater supply. I used a transformer from a tape deck. I dont know what the performance is going to be like. If the thing has no RF amplifier it may be very mediocre. How many IF cans are there? If you cannot find a VT501 beam tetrode then using another valve such as a EL32 or a 6V6 may be necessary with such re-working of the output stage as necessary. At least the rest of the valve lineup contains no surprise for you. I imagine there were simply so many VT501's around because nobody else thought they would be any use except in a transmitter.