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Old 6th Dec 2018, 1:56 pm   #1
LyntonP
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Default Restoration novice. Philips B3G63A.

Last week I became the proud owner of a 1956 Philips B3G63A. Many thanks to Martin for the gift!
As an absolute novice to restoration of valve sets I have been reading many of the articles on this forum regarding what approach should be taken with regards to correct process (even the one that said don’t attempt a Philips as your first project!
I am now armed with an isolation transformer, several multimeters, a scope, a circuit diagram, several soldering irons, and at this stage some trepidation of the voltages I am likely to encounter.
The most common piece of advice I have read is don’t plug the set in until all the old capacitors have been changed.
On inspection nothing in the set seems to have suffered any significant damage but I understand that looks can be very deceiving. All I have done up to now is give the set a good clean.
On the subject of capacitors I can read their value from the circuit diagram but this gives no indication of their safe working voltage. As I said I am a novice and I suppose the more experienced members could look at a schematic and suggest the correct values of voltages throughout the circuit.
I am hesitant to go and buy components that will be at best unsuitable and at worst dangerous.
I have in the past constructed some simple equipment (RTTY terminal, dummy loads, power supplies etc) but never the restoration of old valve gear.
What advice would the forum offer? Are there any courses available as there used to be at local technical colleges when I sat my amateur exams over twenty years ago?
Any advice would be very welcome.
Thanks
Lynton
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Old 6th Dec 2018, 2:07 pm   #2
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Default Re: Restoration novice. Philips B3G63A.

Have a wade through this lot:

https://www.vintage-radio.com/repair...ion/index.html

Lawrence.
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Old 6th Dec 2018, 2:12 pm   #3
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Default Re: Restoration novice. Philips B3G63A.

Please don't change all the capacitors. It's completely unnecessary and can be a recipe for disaster. I'd just change C52 and C54 (manufacturer's sheet) the output valve coupling capacitors and then do some fault finding.

The service sheet gives voltages for many capacitors.
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Old 6th Dec 2018, 2:28 pm   #4
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Default Re: Restoration novice. Philips B3G63A.

The HT voltage is 240V so chose capacitors well above this. 350V or 500V.
Do NOT change all capacitors on a whim, you will likely introduce faults which can be very difficult to find.
Check and preferably change the capacitor connected to the EL84 output valve grid.
Start up using a lamp limiter.
The radio has a transformer so the chassis should not be live but an isolation transformer will do no harm.

If solder tags are used, I wind a helix on the new components using a small watchmakers screwdriver as a former. This helix can then be slipped over some of the lead of the old components and soldered. In the case of a PCB being used, the old component could be removed from the board and the new one fitted in its place.
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Old 6th Dec 2018, 3:10 pm   #5
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Default Re: Restoration novice. Philips B3G63A.

Re post #3, the output stage requires two capacitors to be replaced to avoid the possibility of a positive voltage appearing on the output valve grid. These are C59 and C60. (Trader service sheet). If either of these is electrically leaky, a positive voltage can appear on the grid of the EL84 (V6). Tony
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Old 6th Dec 2018, 3:22 pm   #6
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Default Re: Restoration novice. Philips B3G63A.

Lyndon, regarding your question about technical college courses, unless I am completely wrong I don’t think you will find any courses being run today on servicing and restoration of vintage Radios etc.
You have been provided with much information thanks to Lawrence, certainly a lot to study. It would be nice if there was an experienced vintage radio club or person living near to you, maybe you could ask via local paper.
Cheers
John
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Old 6th Dec 2018, 3:23 pm   #7
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Default Re: Restoration novice. Philips B3G63A.

Sorry Lynton
cheers
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Old 6th Dec 2018, 4:58 pm   #8
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Default Re: Restoration novice. Philips B3G63A.

Hi Lynton. You'd be lucky to find courses on anything these days with all the Local Government cut backs that have taken place but the "in house" info is truly excellent. Chas Miller who runs the Radiophile Mag, does Instructional Workshops from time to time where you take your own set along for Guidance.
He's written a good book on the subject, as have many others including Tony Thompson [Aerodyne] who is on the Forum currently "mothballing" his website. Given your Amateur Radio background I wondered if you might be in touch with any Radio Club members who may have a restoration inclination. Then I saw that the South Lancs Society based at Bickershawe Labour Club is having a Winter Rally on Sunday. Might be worth going along perhaps? You'd probal pick up a few components or maybe another radio at least. I think I went there last year at one point for the summer version.

Dave W
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Old 6th Dec 2018, 11:49 pm   #9
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Default Re: Restoration novice. Philips B3G63A.

Gentlemen many thanks for all the replies most encouraging.
Lawrence I have been reading through this information over the last week. Very comprehensive.
Graham and Tony I am a little confused about manufacturers sheets and traders sheets? Are they both the same? Presumably the circuit diagram is the same but are components numbered the same? E.G. C52 on my diagram (Traders sheet 1374) connects the ground via a resistor to one of the grids on V3, and C54 is connected to the wiper of the volume control? Capacitors 59+60 which have also been mentioned are shown on the tone control on my schematic?
Apologies for my ignorance.
The manufacturers information would seem to be the best to follow where can I find this?
Once again thanks for your help
Lynton
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Old 7th Dec 2018, 12:07 am   #10
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Default Re: Restoration novice. Philips B3G63A.

Sorry about the wrong info re the Winter Rally Lynton. I seem to have confused a 9 in the notice with this Sundays date when the event took place on December the 1st.

Dave
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Old 7th Dec 2018, 12:34 am   #11
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Default Re: Restoration novice. Philips B3G63A.

Quote:
Originally Posted by LyntonP View Post
Graham and Tony I am a little confused about manufacturers sheets and traders sheets? Are they both the same? Presumably the circuit diagram is the same but are components numbered the same? E.G. C52 on my diagram (Traders sheet 1374) connects the ground via a resistor to one of the grids on V3, and C54 is connected to the wiper of the volume control? Capacitors 59+60 which have also been mentioned are shown on the tone control on my schematic?
The Trader Sheet and manufacturers sheet are not the same. The circuits are (should be) the same but component references are likely to be different. Trader sheets were a helpful guide made available to the general trade repairers in a magazine called Trader (not surprisingly)! It gave the circuit and abridged (sometimes very abridged) circuit information and alignment instructions. It was a 'better than nothing' guide to traders who perhaps were not authorised service agents for particular sets or were on a tight budget and didn't want to buy a manufacturers manual for what may have been a one-off repair. Having said that, the Trader sheets generally did a good job and gave enough information to 'get the job done' which is really what mattered.

Manufacturers service manuals on the other hand were full and comprehensive giving parts list with part numbers and full details of circuits and modifications. Many of these were supplied free to authorised dealers or at greatly reduced prices.

Quote:
The manufacturers information would seem to be the best to follow where can I find this?
Once again thanks for your help
If it's available, click on the 'service data' panel top right. Paul has put together a CD containing Trader and Manufacturer service sheets of thousands of models.

As a footnote, these sets are not the easiest to start with. Whatever you do please be careful with the drivecords that control the tuning....there are four of them and believe me....you don't want to accidentally break any of them......!!!
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Last edited by Sideband; 7th Dec 2018 at 12:42 am.
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Old 7th Dec 2018, 1:17 am   #12
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Default Re: Restoration novice. Philips B3G63A.

Manufacturers service data ordered.
I understand the comment about the tuning dial cords. The AM works fine but the FM is a little slippery.
Again thanks for the info and help.
Lynton
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Old 7th Dec 2018, 5:19 am   #13
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Default Re: Restoration novice. Philips B3G63A.

Quote:
Originally Posted by LyntonP View Post
The most common piece of advice I have read is don’t plug the set in until all the old capacitors have been changed.

Lynton
Don't!!!

Don't know were that advice came from but its wrong.
Compulsive Capacitor Changing wrecks sets.
If you change the silver mica ones in the set front end the alignment goes out of the window. They are very reliable.
Change the output valve grid 1 cap first by all means, it will be leaky and can destroy the output transformer, output valve or the mains transformer.
Then see if it works.
The various electrolytic caps, reservoir, smoothing and cathode bypass will likely be best changed but only after checking.
Its only the waxy paper and foil caps that habitually go leaky but in some locations it will make very little difference.
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Old 7th Dec 2018, 11:28 am   #14
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Default Re: Restoration novice. Philips B3G63A.

There is a great deal of useful information here that will prove useful guidance. Not a lot to add, other than to reinforce the point about NOT changing all the capacitors. Also note that you should change only ONE component at a time, testing for the result. Snipping out two or three in one go is a recipe for errors, either in location (re-affixing to the wrong point) or in value confusion.

Top tip from me, especially with 'busy' under-chassis like so often the case with Philips receivers, take close-up digital photographs before you begin. If there's no camera to hand that is suitable, make careful, simple sketches and diagrams showing what is connected to what. This can save you long hours of head-scratching by preventing you from inadvertently creating a weird fault.

Take your time.

Tony
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Old 7th Dec 2018, 11:33 am   #15
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Default Re: Restoration novice. Philips B3G63A.

One general suggestion when servicing these sets, (or any set with drive cords) Lynton, is to keep the soldering iron well away from the dial drive-cords. If you touch a nylon drive cord with the iron, you will probably find that you have made yourself the annoying and difficult task of replacing it. Tony.

Last edited by Station X; 7th Dec 2018 at 12:11 pm. Reason: Earlier post corrected.
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Old 7th Dec 2018, 8:39 pm   #16
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Default Re: Restoration novice. Philips B3G63A.

Quote:
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If you touch a nylon drive cord with the iron, you will probably find that you have made yourself the annoying and difficult task of replacing it. Tony.
...and these are annoying and difficult....!
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Old 7th Dec 2018, 10:04 pm   #17
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Default Re: Restoration novice. Philips B3G63A.

Tony I had planned to visit the rally at Bickershawe LC but was diverted in order to collect an isolating transformer.
Lynton
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Old 7th Dec 2018, 10:51 pm   #18
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Default Re: Restoration novice. Philips B3G63A.

Don't know were that advice came from but its wrong.
Compulsive Capacitor Changing wrecks sets.
If you change the silver mica ones in the set front end the alignment goes out of the window. They are very reliable.
I take on board the suggestions about capacitor replacement. A lot of on line videos of restoration come from the US and Canada where the phrase "Needs a complete recap" is often used. I am familiar with the problems of paper/foil capacitors but my own set seems to have none. I have been studying the Philips service sheet and yes the component numbers differ. Spent part of the evening looking for replacement parts and have noticed how things have changed in their catalogues since last looked at them. Even my local-ish stockist doesn't carry many of the components that were common in my ham days. It will be a slow process and I will not make any rash changes before asking advice from the forum.
I am enjoying and learning from the process but please bear with me if I seem to ask the same question twice since I do not want to make a fatal error.
I removed the rectifier valve and checked the voltages from the transformer and all seems in order so I need to order some bits and pieces to move the process along.
Yet again thanks for the help
Lynton
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Old 7th Dec 2018, 11:40 pm   #19
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Default Re: Restoration novice. Philips B3G63A.

Where the manufacturer's service data is available as well as a Trader Sheet, the maker's data is invariably more comprehensive, and this is so with your model. The Trader Sheet is four pages - the Philips data is 18 pages, though it covers three variants of the set - one a radiogram. If - as you progress with the set - you state any component numbers such as R28, C43 or whatever, always mention which data you are using because the numbering used on Trader Sheets and Maker's sheets rarely coincide, and it can get very confusing if the source isn't stated.

If you read and digest the notes that Lawrence pointed to, it's a good idea to make a 'lamp limiter' and when first trying out the set live, to power it through the limiter, which will limit the current drawn by the set if there are faults which would cause it to draw excessive current. If you're lucky, given that the set appears not to have been tampered with, you might find it works. It's always easier to rectify and defects or replace any components on a working set than one that's silent.

There are lots of tests you can safely do with the set not plugged into the mains. For example, you can look at the circuit to see which pins of the valves are the heater pins, and check each valve it turn with your meter on the Ohms range (say 200 Ohm), to see if all the heaters are intact. You can also locate and check each resistor noting it's resistance and comparing it with what the data says. If any are more than +/- 20% or so, highlight those as possible (not probable) candidates to change. You can check the continuity of switch contacts, the condition of any wiring to see if it's perished, or if you see any signs of overheated scorched components.

Before you change any component at any stage, make sure you've taken a photograph so you have a reference in case you make any mistakes.

As to 'changing capacitors' the ones that cause most trouble are waxed paper capacitors (sometimes referred to as 'tubular paper capacitors'), and certain makes of moulded capacitors. As Graham says, C52 and C54 are in part of the circuit where problems can arise, and would be high on the list to change as a precaution, but many of the capacitors in your set are ceramic, and generally reliable. Some are in tuned stages, which on no account should you change unless you've first diagnosed that they're faulty.

As to the working voltage (VW) of replacement capacitors, that is stated on the maker's data, and you'll see that apart from one (C55 - 800VW), the highest is 400VW. Generally, the most common replacement capacitors that are used are polyester film ones, that are yellow. Typically they're 630 VW so would cover all eventualities except C55, for which you could use a 1,000 VW capacitor. That's DC Voltage by the way. Sometimes both the AC and DC rating is stated and the AC voltage will be lower - for example, it may state 500V DC/300V AC. (All of the capacitors in your set except C58,59,60 & 64, associated with the heater supply and the AC input to the rectifier valve, operate on DC).

If you get excessive hum, it's possible that the reservoir and smoothing capacitors C1 & C2 - in one can above the chassis - might need changing, but you can deal with that and seek advice when you have a working radio.

You'll see on the maker's data that the highest voltage (HT line) is 240 Volts, but to an extent, that depends on the mains input voltage. (Make sure your mains input selector is set to 245V). Most maker's data will state that voltage measurements were taken using an AVO8 analogue meter, which has an impedance of 20,000 Ohms per Volt, ('OPV') but unusually perhaps, the measurements on your set were made using a Valve Voltmeter with a 10 MegOhm impedance, which is on a par with most modern digital multi-meters - even cheap ones. If you were to use an AVO 8 (20,000 OPV) or worse still an AVO7 (1,000 OPV) or other analogue meter, (one with a needle and dial rather than a digital readout) you will get lower, and hence misleading voltage results, so it's best to use a digital multi-meter.

Without wishing to spook you, it's quite a complex set on which to 'cut your teeth', being both FM and AM, with a high component count. Also, looking at the diagram of the underside of the chassis, is a bit of a 'rat's nest', so the fewer components that you have to change, and only by proper diagnosis, the greater the chance of success.

You'll already have realised that it won't be the lack of advice that will beset you, rather than perhaps too much of it, and maybe I've added to that, but I hope these wordy notes will prove helpful.

Good luck in your endeavours Lynton.
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Old 8th Dec 2018, 5:59 pm   #20
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Default Re: Restoration novice. Philips B3G63A.

Thank you David for the excellent reply, again containing valuable knowledge that I at this time lack. All information is being taken on board and I do not intend to rush the project. Won’t have much chance this weekend as I am busy with household tasks but it will be like the man eating the elephant-a bit at a time!
All pieces of knowledge are being compiled in order to have a successful outcome with a working radio.
One question. Where does one go to buy bits and pieces? I know of RS and Farnell but are there any outlets that specialise in bits and pieces for older radios?
OK enough for now so it’s back to the domestic chores for a while.
Thanks for all the help.
Lynton
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