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-   -   1948/1949 Philips type 520A television and radio (https://www.vintage-radio.net/forum/showthread.php?t=128382)

grahamperrin 30th Jul 2016 7:25 am

1948/1949 Philips type 520A television and radio
 
5 Attachment(s)
I can't remember where I got this set, probably in the 1980s, but it was the closest I came to a 'project'.

Attachment 127986 Attachment 127987 Attachment 127988

The radio worked, and I could hear the sound of TV channels. As far as I recall, it had symptoms of a failed frame output transformer.

In the service manual I see a frame output choke (S57 on a diagram, replacement part MK.511.88) but not a frame output transformer. Does that make sense? Or am I missing something?

Long ago I kidded myself that the 520A was a rare and valuable secondhand set, because it was originally more than twice as costly as the relatively commonplace Bush TV22. I'm almost certain that the 520A was priced at 112 or 115 guineas.

Back to reality :-) it's not valuable, one was auctioned for 48 in 2009.

Mullard equivalent

At http://www.thevalvepage.com/tvmanu/mullard/mullard.htm I see –

Quote:

…MTS501 is a repackaged Philips 520A and the MTS684 the Philips 683U. They even cost the same…
– but there, the (1950/1951) price of the MTS501 is 79-16-0, and this Jonz Valve Page photograph of a (pre-October 1949) MTS521 (102-18-0) – Attachment 127985– appears to be an almost perfect match for my 520A: Attachment 127989

The fabrics that cover the loudspeaker grille may be different. And if you wonder how the fabric of mine became so tattered, it's thanks to cats. In the first photograph above there's Pickle, emerging from a brief expedition into the shockingly dusty interior.

More on the Mullard MTS 521/521A: Postscript: http://www.thevalvepage.com/tvmanu/philips/philips.htm confirms that the 520A was also released as the Mullard MTS521.

Distinction

1934/1945 Philips 520A radio pictured at http://www.jllacer.com/Euro_Radios/philips520A.htm

thermionic 30th Jul 2016 8:12 am

Re: 1948/1949 Philips type 520A television and radio
 
Hello Graham.

I have the Mullard MTS 521 on my 'project pile'. Do you intend to restore yours? I shall follow your progress with interest if you do.

Good luck with it. You will find plenty of excellent advice from experienced TV engineers here to guide you to, hopefully, bring your project to a successful conclusion.

SimonT.

grahamperrin 30th Jul 2016 8:43 am

Re: 1948/1949 Philips type 520A television and radio
 
Thanks Simon

I imagine it becoming a project after I retire, if circumstances allow …

FERNSEH 30th Jul 2016 9:18 am

Re: 1948/1949 Philips type 520A television and radio
 
Long ago I kidded myself that the 520A was a rare and valuable secondhand set, because it was originally more than twice as costly as the relatively commonplace Bush TV22. I'm almost certain that the 520A was priced at 112 or 115 guineas.
Back to reality it's not valuable, one was auctioned for 48 in 2009.


But surely it's not what it's worth in an auction but the fact it is one of the most technically interesting TV sets to be made in late forties.
I'm of the opinion that the 520 was designed in Mitcham rather than Eindhoven.

DFWB.

grahamperrin 30th Jul 2016 3:53 pm

Re: 1948/1949 Philips type 520A television and radio
 
Quote:

Originally Posted by FERNSEH (Post 866628)
… one of the most technically interesting TV sets to be made in late forties. …

Please: can you (or Simon, or anyone with relevant technical knowledge) explain what makes a set such as this so interesting, compared to other sets from the same era? I don't doubt what you say, I'm just curious.

Around five years ago I might have given it away – half-expecting the donation to be either declined, or politely discarded by a new owner. So now, it's a pleasant surprise to find other people interested.

Thanks

Heatercathodeshort 30th Jul 2016 5:54 pm

Re: 1948/1949 Philips type 520A television and radio
 
It is a vintage television restorers delight. Very quirky, typical Philips design with an strange chassis with some odd valves even for 1949. It's all about the pleasure of restoring these old receivers. Value and cost on the whole plays no part of it.
These give an excellent picture in their day and would still be capable of very good results today given a good overhaul.
I would agree with David, I'm also of the opinion that this is a Mitcham design, probably the first one after the difficulties with the design of television receivers at Mitcham and the clash with Eindhoven. I hope we see a picture on it one day. Regards, John.

grahamperrin 30th Jul 2016 7:08 pm

Re: 1948/1949 Philips type 520A television and radio
 
In retrospect, the opening post probably gave an impression that I'm overly interested in the monetary value, that's not the case. I was initially puzzled by the difference in original costs between the 520A and the Mullard MTS501. Then realised that the corresponding Mullard is truly the MTS521.

More than anything I'd love to, some day, see sets such as this go to a good home (better than mine, with attention from expert restorers). I'm aware of Sets, Parts and Service Information Offered, but that's not why I joined; for now it's far more enjoyable to read people's stories and opinions.

Thanks again

Jac 31st Jul 2016 5:47 am

Re: 1948/1949 Philips type 520A television and radio
 
The Philips 520A has a circuitry quite similar to other Philips sets of around that time, like the 563A and 663A.
A big difference is that is has no mains transformer, hence the special valves to make a 0.2A heater chain.

Indeed it would be nice to see a picture on it!

Jac

FERNSEH 31st Jul 2016 10:13 am

Re: 1948/1949 Philips type 520A television and radio
 
Good morning Jac,
Just like the 563A there are some quite adventurous circuits in the 520A and 521A. The sound circuits in particular. Switched to radio operation the set performs just like a conventional receiver using 0.2amp heater chain valves, CCH35, EF39, EBC33 and CL33, Just to add to the confusion the radio HT rectifier is a 0.1amp heater type UY21. Radio IF is 470Khz.
On television all the 0.2amp radio valves remain in the circuit, the CCH35 performs as the sound frequency changer, The television sound IF is 9.8Mhz.
When switched to television an additional sound IF amplifier stage is introduced using an EF50.
Most of the television circuits resemble the 563A, however because no mains transformer is employed for the higher HT voltage required by the line timebase a voltage doubler circuit is used by employing a PZ30 double diode.
Thus the set cannot be used on DC mains.
Information for the Mullard version, the MT521 can be found in pages 592 to 601 of volume II Radio and Television Servicing by Molloy and Poole.

DFWB

stevehertz 31st Jul 2016 4:52 pm

Re: 1948/1949 Philips type 520A television and radio
 
The world of collectable vintage TVs has its own rules and trends when it comes to the value of sets.

1) Being rare does not necessarily make a vintage TV valuable.
2) TV sets are generally quite large and most collectors only have so much room to keep them, so often - pre war sets excepted - console sets are less sought after.
3) Like any aspect of vintage wireless and TV, appearance plays an important part in desirability, and often console sets can be quite ugly and bulky looking. Others are cute or handsome.
4) All pre-war TV sets are rare and sought after and hence are valued highly.
5) Trends and fads are as prevalent in vintage TVs as they are in most other collectable hobbies. Bush TV22s always used to be sought after and would fetch a comparatively high price. These days you can now pick up a Bush TV22 at the same kind of prices - or less - than you could in the 70s or 80s. However, I think this is partly due to their greater availability as a result of auction sites and the expanded supply chain that they bring.

HamishBoxer 31st Jul 2016 5:21 pm

Re: 1948/1949 Philips type 520A television and radio
 
Totally agree re Bush TV22s as I remember the days they were 250 plus,now possibly 150 max.

Maarten 1st Aug 2016 2:46 am

Re: 1948/1949 Philips type 520A television and radio
 
A Mitcham design seems plausible, but can easily be confirmed by looking at an actual set and its documentation.

Code numbers of significant parts depend on the place where a set was designed, so one would expect to see code numbers starting with MK instead of A3 for more than a few components in the documentation and in the actual set as far as code numbers can be found there.

Also, the place where a set was manufactured depends loosely (more or less so depending on the era and the kind of equipment) on where it was designed. If the serial number starts with M for manufacture in Mitcham rather than E, chances are it was at least partially designed in Mitcham as well.

Last but not least the presence of an execution/destination suffix behind the type number. This doesn't say anything about where a set was designed, but it can give an indirect clue. If a suffix /15 is present, the set was intended for the UK but might have existed in versions for other countries as well. The chance it was designed in one of the destination countries instead of centrally, is a bit lower in that case.

Jac 1st Aug 2016 10:51 am

Re: 1948/1949 Philips type 520A television and radio
 
1 Attachment(s)
Maarten,

There is a big chance that the serial number has no letter in front.
Perhaps grahamperrin is willing to post a picture of the type plate of his 520A?
The 383A/15 in my collection is of about the same era and just has a 4-digit number.
The service manuals issued by Philips for this generation of sets state Croydon as the service department, which does not inform us of the development or manufacturing location.

Later sets, like the 385U/15, have M in front of a 4-digit number.

All these sets have some Eindhoven components, but certainly a majority of part references start with MK or MS.

Jac

Duke_Nukem 1st Aug 2016 6:55 pm

Re: 1948/1949 Philips type 520A television and radio
 
Thanks to Graham I've now fixed the wee typo on the Mullard Page.

BTW if anyone has the Mullard version of the set getting in their way, I know of a good home ;D

TTFN,
Jon

grahamperrin 1st Aug 2016 6:59 pm

Re: 1948/1949 Philips type 520A television and radio
 
Thanks folks

I'm nursing a cold at the moment, I'll get to the serial number maybe tomorrow.

Maarten 1st Aug 2016 7:37 pm

Re: 1948/1949 Philips type 520A television and radio
 
From Jac's statement that most part numbers start with MK and MS, it is at this point quite likely to have no letter or an M in front of the serial number as it makes sense that British designs were manufactured locally with only some parts imported from Eindhoven.

grahamperrin 2nd Aug 2016 6:04 am

Re: 1948/1949 Philips type 520A television and radio
 
https://goo.gl/photos/DU76Ep5h3qZh4xbY9

520A/15
MM 2884

Also on the plate:
  • no voltage, AC, 230 W (I guess that's a mistake)
  • A1872 (I guess that's a generic reference for the plate itself).
Quote:

Originally Posted by Jac (Post 867094)
a majority of part references start with MK or MS.

I see many MK but (at a glance) no MS.

If it helps to date my service manual: eight notes under ADDITIONS AND CORRECTIONS on page 19 and when I flip that page, there's 'PR1789'.

Jac 2nd Aug 2016 6:27 am

Re: 1948/1949 Philips type 520A television and radio
 
That's interesting!

I hadn't expected this. Even 2x M on the plate!
The 230 W will be correct - these sets draw about 1 A.

Jac

FERNSEH 2nd Aug 2016 10:03 am

Re: 1948/1949 Philips type 520A television and radio
 
2 Attachment(s)
Circuit diagrams of the Philips 520A and Mullard MTS521.
V1 (CCH35) functions as the mixer-oscillator on radio and TV sound, the triode oscillator section is common to radio and television. V8 is the vision and sound RF amplifier. V9 is the vision frequency changer. It's likely because of all this complication in the signal circuits none of these receivers were converted to Band 3.

DFWB.

Maarten 3rd Aug 2016 2:10 am

Re: 1948/1949 Philips type 520A television and radio
 
The double M on the plate is something I've never seen before and may indicate another factory than a single M (or it was a simple error - by any chance, is the first M printed and the second M stamped?) but it is at this point extremely likely the set was both designed and manufactured in Great Britain.

Interestingly, the type plate itself was designed in the Netherlands as A1 872 is a Dutch issued part number missing the last 2 or 3 digits (it would be nice if you could decipher them).

Edit: I only see now, that you linked some (very nice and sharp) pictures. The second M is indeed stamped. The stamping machine was probably adjusted to non-pre printed type plates so for practical intents and purposes I would consider this a single M. Also the last (5 even) characters of the type plate's article code A1 872 23.0/A are visible, quite interesting for my archives. The voltage not being stamped wasn't a mistake but rather usual practice for sets with adjustable mains voltage.

Aerodyne 3rd Aug 2016 8:44 am

Re: 1948/1949 Philips type 520A television and radio
 
Would someone kindly elaborate on the 'clash' between Mullard and Philips, as mentioned in this thread?
Tony

Maarten 4th Aug 2016 12:30 am

Re: 1948/1949 Philips type 520A television and radio
 
I would like to know as well. Mullard was a full subsidiary of Philips from 1927, but of course they had their own design staff as was usual for many Philips companies (internal cooperation and internal competition were both stimuli for innovation).

Heatercathodeshort 4th Aug 2016 7:16 am

Re: 1948/1949 Philips type 520A television and radio
 
Eindhoven insisted in designing the UK television receivers that were built at Mitcham.
This caused difficulties at the factory due to the fact that actual live transmissions were not available in the Netherlands and receivers suffered from design faults. Modifications were constantly taking place and the UK team threatened to withdraw their cooperation. Philips eventually gave in and all receivers from the 520A were designed very successfully by the British design team.
Back in the shop days I had several customers that worked at the Philips Mitcham works as it was known in the late 1940's. It was very informative chatting with them. In the end the difficulties were resolved resulting in a fine range of British receivers designed at the Mitcham Works continuing into the early 80's. John.

Jac 4th Aug 2016 7:46 am

Re: 1948/1949 Philips type 520A television and radio
 
That's interesting John.

Do you know if the 383A and 663A were made before or after the 520A?
I have both a 383A and 663A, and there is no M in the serial number.

Jac

FERNSEH 4th Aug 2016 8:14 am

Re: 1948/1949 Philips type 520A television and radio
 
Hello Jac,
The 383A and 683A have much in common with certain pre-war models like the 2405 etc. According to the service data the 520 was designed to receive the Birmingham transmitter so it's safe to say that it was on sale after the 383A had gone out of production. The 385A was marketed at same time as the 520A.

DFWB.

Aerodyne 4th Aug 2016 8:23 am

Re: 1948/1949 Philips type 520A television and radio
 
Thanks for that sidelight on Philips' centralised approach, John.
Tony

grahamperrin 4th Aug 2016 8:29 am

Re: 1948/1949 Philips type 520A television and radio
 
Thanks folks.

Quote:

Originally Posted by Maarten (Post 867553)
The stamping machine was probably adjusted to non-pre printed type plates so for practical intents and purposes I would consider this a single M.

+1

I had the same guess about pre-printing.

Jac 4th Aug 2016 8:35 am

Re: 1948/1949 Philips type 520A television and radio
 
Thanks David,

Yes, you're absolutely right. I should have noticed that myself!
Were the 463A and 563A manufactured earlier than the 383A and 663A?
Or about the same time?

Thanks.
Jac

grahamperrin 4th Aug 2016 11:56 am

Re: 1948/1949 Philips type 520A television and radio
 
Quote:

Originally Posted by Maarten (Post 867553)
… the type plate's article code A1 872 23.0/A …

Might the tail of that be 23.O/A (uppercase o, not a zero)? On one hand, the character is more rounded than I would expect for a 0; on the other hand, I have no other plate (with other examples of the typography) to compare against.

OVERZEE/ANGLO maybe?

Maarten 4th Aug 2016 1:26 pm

Re: 1948/1949 Philips type 520A television and radio
 
Not based on typography but on the construction of the Philips code system, the digit behind the . is the revision number. If the design is changed, it is incremented. After it reaches 9, a new code number is used.

It is indeed true that various different type plates were used for different destination markets, but they had a different code number within the same series and not simply a different revision number. As far as suffixes go, I'm not exactly sure why and how they were used. Speculation says the /A may have something to do with the pre-printed M which may or may not have been pre-printed at the same time the rest of the plate was printed.

To illustrate, some similar code numbers of type plates:
A1 871 99 "PHILIPS Made in Holland/Importe de Hollande" with Nemko/Demko approval marks (used on some 1948/1949 export radios)
A1 871 99.0 "PHILIPS Made in Holland/Importe de Hollande" with Nemko/Demko approval marks (used on various general market and export sets around 1940-1947)
A1 871 991 "PHILIPS Made in Holland/Importe de Hollande" with Nemko/Demko approval marks (used on some 1947-1948 models for general markets)
A1 872 23.0/A the plate on the 520A/15 from around 1949
A1 872 27.2 plate on GM4198 measuring equipment

The code number series starting with A1 wasn't used for very long (approximately 10 years with a war in between) so those are the only examples I have but the same principle applies to other type plates and in general to all code numbers from the early 1930's to the early 1960's. I don't know the (probably small) differences between the various A1 871 99 versions so I'll have to compare pictures.

Heatercathodeshort 4th Aug 2016 1:41 pm

Re: 1948/1949 Philips type 520A television and radio
 
The first Philips television manufactured after the war as far as I know is the series with voltage doubler HVR2 rectifiers developing EHT from the pulse available on the anode of the line output valve. No EHT mains transformer was employed despite the chassis containing several large transformers and HVR2 rectifiers.
The first true flyback models had an oil filled transformer[?] and two EY51 EHT rectifiers again in a voltage doubler circuit. Their heaters were powered from the flyback transformer unlike the early model that had the two HVR2 rectifier heaters powered from a specially insulated mains transformer.
It would appear that the 520 was sandwiched between the 385/485 series and the 1100, a truly incredibly reliable receiver. Maybe I'm wrong. John.

Jac 4th Aug 2016 3:10 pm

Re: 1948/1949 Philips type 520A television and radio
 
1 Attachment(s)
Thanks John,

That makes it even more complicated.
The 383A/663A has a mains transformer and voltage doubling with 2x HVR2 from the anode of the line output valve.
To me it is not clear how the line output transformer itself is built, because it is in a sealed 'box'. See attached picture.
(I have no X-ray equipment to look into it.)
It might very well be a laminated iron cored transformer with several wave wound coils, as was not unusual at the time.
Perhaps there is petrolium jelly in the box, as is in the transformer of an experimental Philips projection receiver of an earlier date.

The 385U (no mains transformer - 2x EY51) is dated at October 1949 according to the Trader Sheet (nr 993).
The 1100 ditto August 1951 (Trader Sheet 1051).
The 383A/663A certainly is before the 385U.
Unfortunately I could find no Trader Sheet for the 520A of Mullard equivalent.
There must be date codes in it it somewhere however. Perhaps on the CRT as well.
The Wireless and Electrical Trader has an advertisement of the 383A at January 8, 1949.

The 520A has, as David pointed out, a Birmingham version.
The 383A/663A has not.

So the sequence looks like this:
* 463A + 563A (date??)
* 383A + 663A (early 1949?)
* 520A (1949?)
* 385U (Oct 1949)
* 1100 (Aug 1951)

Jac.

FERNSEH 4th Aug 2016 4:43 pm

Re: 1948/1949 Philips type 520A television and radio
 
I'm certain that all the models marketed before the 520A were designed to receive the AP transmitter, no Birmingham versions. Is it possible the models 463A and 563A were nothing more than alternative cabinet presentations of the 383A?
Jon's 563A: http://www.thevalvepage.com/tv/philips/563a/563a.htm
The date code on the two TCC Visconol capacitors in the EHT doubler circuit is 477, July 1947. I'm trying to determine the date codes on the Philips black tar "goudron" capacitors. More about that later.
The contributor to this French TSF forum has his problems with those condos au goudron:
http://www.doctsf.com/forum/viewtopi...=8860&start=12

DFWB.

Jac 4th Aug 2016 6:06 pm

Re: 1948/1949 Philips type 520A television and radio
 
Good evening David,

Yes, that's very well possible.
Although it is not clear to me what the difference between a 463A and a 383A is. I couldn't find a picture of a 463A.
The service manual for the 383A/663A refers to the manual of the 463A/563A for the circuit description.
Do any 463A's actually (still) exist?

I think the visconols in my 383A have 4811 as date code.

Regards,
Jac


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