Repro alert! Philips 13R634 /15Z - UK Vintage Radio Repair and Restoration Discussion Forum

ColinB · 30th May 2020, 5:51 pm

Hi,

Currently pitting my wits (such as they are) against a repro of the famous Philips 634A, the smaller, 1970's 634R.

I can't get FM working at all, although both MW and LW perform well.

Does anyone have any idea where the problem may be, and or have a schematic available that they wouldn't mind sharing? Google doesn't seem to find one, which was a surprise.

Thanks in advance.

Cheers,
Colin

AC/HL · 30th May 2020, 6:18 pm

The only reference I can find suggests to look here for information! but it may be based on a Philips Hong Kong chassis.

ColinB · 30th May 2020, 6:32 pm

Yes it's odd. I do seem to recall there having been a mention of it, years ago, on the main website rather than the forum (https://www.vintage-radio.com/), but I can't find it now to save my life.

Philips210 · 30th May 2020, 6:47 pm

Hi.

The Philips 13R634 service information is in the Radio and Television Servicing 1981/82 book. In the description it mentions that it is a replica of model 634 from 1933.

I can scan the info if required.

Regards,
Symon.

ColinB · 30th May 2020, 6:59 pm

Hi Symon,

If you could, that would be a massive help, thanks very much indeed. Very much appreciated. I'll PM you my email address.

Thanks!

Colin

Philips210 · 30th May 2020, 8:03 pm

Hi Colin.

Please see attached for service info.

Regards,
Symon

ColinB · 30th May 2020, 9:14 pm

Hi Symon,

Thanks for scanning this in for me and posting it, that's a great help.

Cheers,
Colin

TonyDuell · 30th May 2020, 11:12 pm

There's a couple of bits of that circuit that I don't understand (nothing new there!)...

Firstly C58. One end is earthed at the emitter of TS5. The other end goes to 'BB' which seems to be earthed in the PSU section of the circuit.

Secondly, what is TS11 doing (and why the '6V' with +ve and -ve markings near it). Is this an external 6V power input, with TS11 acting as a diode to prevent the set's PSU from attempting to power whatever is connected there?

ColinB · 31st May 2020, 12:23 pm

Hi Tony,

I'm not sure myself yet to be honest. It's a shame how much circuitry there is that is not common between AM (which works on my set) and FM (which doesn't).

My initial plan of attack is to check the DC conditions around the transistors and just go from there I think. I had hoped that just cleaning the band switch would fix it, but no such luck!

Cheers,
Colin

stevehertz · 31st May 2020, 2:49 pm

I bought one of these new back in the 80s, and sold it not so long along, boxed. I was a little disappointed at its cosmetic detail. Ok, it's plastic, I don't expect it to be wood, but I just expected a nicer looking, slightly larger (than it was) reproduction of the classic 634A, and it most certainly wasn't, very cheap looking. Best of luck with the repair, I wish I could help you.

Cobaltblue · 31st May 2020, 5:51 pm

I wonder if it's the same radio you're thinking of Steve?

These were made of MDF the "Bakelite" escutcheon made of plastic.

They were 2/3rds original size.

The original WHD 16.9 x 19.3 x 11.4 inch and the copy 11.5 x 12.5 x 7.5 inch

I offered one for sale 5 years ago I think in the end I sold it on the B&B at RWB as I had (and still have) another one.

https://www.vintage-radio.net/forum/...d.php?t=116771

Cheers

Mike T

ColinB · 31st May 2020, 6:02 pm

That's interesting, mine is certainly made out of MDF, and is certainly attractive enough. For a repro, it seems to be fairly well screwed together.

It's certainly smaller than the genuine article, but it's still a 'sensible' size for a radio set as we would understand the term, so that's no bad thing in the grand scheme of things. AM performance seems reasonable, due to the internal rod aerial. As for FM, (hopefully!) watch this space

stevehertz · 31st May 2020, 6:43 pm

Quote:

Originally Posted by Cobaltblue

I wonder if it's the same radio you're thinking of Steve?

These were made of MDF the "Bakelite" escutcheon made of plastic.

They were 2/3rds original size.

The original WHD 16.9 x 19.3 x 11.4 inch and the copy 11.5 x 12.5 x 7.5 inch

I offered one for sale 5 years ago I think in the end I sold it on the B&B at RWB as I had (and still have) another one.

https://www.vintage-radio.net/forum/...d.php?t=116771

Cheers

Mike T

Mike you're right. Dohh.. mine was a 'repro' Radio Rentals set done in 'the style of' a Philips 634. Very different animal and yes I do remember the 2/3 repro one. A photo of my pathetic one is below - no wonder I was disappointed!

Philips210 · 1st Jun 2020, 7:20 pm

Quote:

Originally Posted by TonyDuell

There's a couple of bits of that circuit that I don't understand (nothing new there!)...

Firstly C58. One end is earthed at the emitter of TS5. The other end goes to 'BB' which seems to be earthed in the PSU section of the circuit.

Secondly, what is TS11 doing (and why the '6V' with +ve and -ve markings near it). Is this an external 6V power input, with TS11 acting as a diode to prevent the set's PSU from attempting to power whatever is connected there?

Hi Tony

Yes, I thought that seemed irregular. Maybe there's an error on the circuit diagram and maybe Colin can confirm this by checking the connections to C58 etc.

For the no FM fault, I'd still like to prove the switching is not responsible. As a first check, continuity tests on each contact set at different waveband switch settings will prove the point. A Voltmeter check at contact set A13-A15 should give about 1.2V when in the FM position. I'd then go on to check the DC conditions on the transistors in the FM front end and IF sections. Then maybe injecting a signal to see where it's going amiss. There could also be a switching fault around the AM/FM detector stages possibly? Just a few thoughts.

Regards,
Symon

30th May 2020, 5:51 pm	#1
ColinB Heptode Join Date: Apr 2003 Location: Newton Abbot, Devon, UK. Posts: 761	Repro alert! Philips 13R634 /15Z Hi, Currently pitting my wits (such as they are) against a repro of the famous Philips 634A, the smaller, 1970's 634R. I can't get FM working at all, although both MW and LW perform well. Does anyone have any idea where the problem may be, and or have a schematic available that they wouldn't mind sharing? Google doesn't seem to find one, which was a surprise. Thanks in advance. Cheers, Colin

30th May 2020, 6:18 pm	#2
AC/HL Dekatron Join Date: Nov 2003 Location: Heckmondwike, West Yorkshire, UK. Posts: 9,642	Re: Repro alert! Philips 13R634 /15Z The only reference I can find suggests to look here for information! but it may be based on a Philips Hong Kong chassis.

30th May 2020, 6:32 pm	#3
ColinB Heptode Join Date: Apr 2003 Location: Newton Abbot, Devon, UK. Posts: 761	Re: Repro alert! Philips 13R634 /15Z Yes it's odd. I do seem to recall there having been a mention of it, years ago, on the main website rather than the forum (https://www.vintage-radio.com/), but I can't find it now to save my life.

30th May 2020, 6:47 pm	#4
Philips210 Nonode Join Date: May 2007 Location: Redruth, Cornwall, UK. Posts: 2,573	Re: Repro alert! Philips 13R634 /15Z Hi. The Philips 13R634 service information is in the Radio and Television Servicing 1981/82 book. In the description it mentions that it is a replica of model 634 from 1933. I can scan the info if required. Regards, Symon.

30th May 2020, 6:59 pm	#5
ColinB Heptode Join Date: Apr 2003 Location: Newton Abbot, Devon, UK. Posts: 761	Re: Repro alert! Philips 13R634 /15Z Hi Symon, If you could, that would be a massive help, thanks very much indeed. Very much appreciated. I'll PM you my email address. Thanks! Colin

30th May 2020, 9:14 pm	#7
ColinB Heptode Join Date: Apr 2003 Location: Newton Abbot, Devon, UK. Posts: 761	Re: Repro alert! Philips 13R634 /15Z Hi Symon, Thanks for scanning this in for me and posting it, that's a great help. Cheers, Colin

30th May 2020, 11:12 pm	#8
TonyDuell Dekatron Join Date: Jun 2015 Location: Biggin Hill, London, UK. Posts: 5,208	Re: Repro alert! Philips 13R634 /15Z There's a couple of bits of that circuit that I don't understand (nothing new there!)... Firstly C58. One end is earthed at the emitter of TS5. The other end goes to 'BB' which seems to be earthed in the PSU section of the circuit. Secondly, what is TS11 doing (and why the '6V' with +ve and -ve markings near it). Is this an external 6V power input, with TS11 acting as a diode to prevent the set's PSU from attempting to power whatever is connected there?

31st May 2020, 12:23 pm	#9
ColinB Heptode Join Date: Apr 2003 Location: Newton Abbot, Devon, UK. Posts: 761	Re: Repro alert! Philips 13R634 /15Z Hi Tony, I'm not sure myself yet to be honest. It's a shame how much circuitry there is that is not common between AM (which works on my set) and FM (which doesn't). My initial plan of attack is to check the DC conditions around the transistors and just go from there I think. I had hoped that just cleaning the band switch would fix it, but no such luck! Cheers, Colin

31st May 2020, 2:49 pm	#10
stevehertz Dekatron Join Date: Sep 2011 Location: Rugeley, Staffordshire, UK. Posts: 8,830	Re: Repro alert! Philips 13R634 /15Z I bought one of these new back in the 80s, and sold it not so long along, boxed. I was a little disappointed at its cosmetic detail. Ok, it's plastic, I don't expect it to be wood, but I just expected a nicer looking, slightly larger (than it was) reproduction of the classic 634A, and it most certainly wasn't, very cheap looking. Best of luck with the repair, I wish I could help you. __________________ A digital radio is the latest thing, but a vintage wireless is forever..

31st May 2020, 5:51 pm	#11
Cobaltblue Moderator Join Date: Dec 2010 Location: Exeter, Devon and Poole, Dorset UK. Posts: 6,863	Re: Repro alert! Philips 13R634 /15Z I wonder if it's the same radio you're thinking of Steve? These were made of MDF the "Bakelite" escutcheon made of plastic. They were 2/3rds original size. The original WHD 16.9 x 19.3 x 11.4 inch and the copy 11.5 x 12.5 x 7.5 inch I offered one for sale 5 years ago I think in the end I sold it on the B&B at RWB as I had (and still have) another one. https://www.vintage-radio.net/forum/...d.php?t=116771 Cheers Mike T __________________ Invisible airwaves crackle with life or at least they used to Mike T BVWS member. www.cossor.co.uk Last edited by Cobaltblue; 31st May 2020 at 6:21 pm.

31st May 2020, 6:02 pm	#12
ColinB Heptode Join Date: Apr 2003 Location: Newton Abbot, Devon, UK. Posts: 761	Re: Repro alert! Philips 13R634 /15Z That's interesting, mine is certainly made out of MDF, and is certainly attractive enough. For a repro, it seems to be fairly well screwed together. It's certainly smaller than the genuine article, but it's still a 'sensible' size for a radio set as we would understand the term, so that's no bad thing in the grand scheme of things. AM performance seems reasonable, due to the internal rod aerial. As for FM, (hopefully!) watch this space