Philips radiogram HX558A

[Geoff 555]

Hello I am starting a new thread on this one ,the other thread being about identification. I hope this is OK. The one thing that worries me a little is that the max. mains adjustment is 220V. Now the mains here is high being minimum 246V and the maximum 250V.I don't want to cook it what are your thoughts/suggestions please.
All the 'black caps will be replaced but at the moment I am hesitating about the main electrolytic as it's a monster with 7 connections on it.
Thank you gentlemen (and Ladies.)
Cheers.
Geoff.

[Nickthedentist]

Hi Geoff,

Hope you're well... and thanks again for the Panasonics

Seven separate connections?? Are you sure? I'd try to re-form it, using the gadget on Paul Stenning's site, well worth making if you can.

As for the mains voltage... try measuring the heater voltage on the valves, and see if it's within spec.

Nick.

[Steve_P]

There's two ways to limit the power. The one I would use is an extra resistor in the live terminal of the mains. This will drag the HT and LT down equally. 30v is a large drop, and so I would drop the supply voltage to everything, even the motor. The quickest way is to put the thing on a variac and measure it's resistance when set to 220v. This is the value to use.

Make sure the resistor you fit is powerful enough!

7 terminals on the smoother? That's a lot. I hope capacitors in Netherlands stuff are better than in British ones!

Cheers,

Steve P.

[Geoff 555]

Hello Thank you to you both Nick and Steve P I thought that 30V was rather a lot, it's a big transformer and to cook it would write the thing off, lots of tappings. Yes 7 tags is the number I couldn't believe it and is 21/2" in diameter and 31/2" long. I will build the reformer as suggested it looks a very useful tool.
Not knowing a lot about it I thought a capacitor dropper might do only because I have a few. When I am a bit farther along I will be back with out doubt.
Cheers.
Geoff.
Nick. Thank you for the enquiry healthwise, still around to worry people!! Going further OT I hope the Panasonic's were OK and you found what you were looking for.
Keep well all.
Geoff.

[Geoff 555]

Hello I need to replace the cartridge and I don't know which one I need, upon investigation it is evident that the deck is a later one, a Garrard 4 speed autochanger, the present cartridge is U/S with very very little output. It is marked 'Garrard' but no number or anything.When the wire is touched with a finger it hums well.
I would like to play stereo and 78's.
It is a turnover cartridge at present.
There is another problem and that is that the deck motor runs as soon as the radio is turned on! There is no switch on the deck.
I have been quite unsuccessful in finding any information on this radiogram, it has not been touched before* and still has the original Philips miniwat valves apart from 1 Madza*.
The large condenser ( with 7 connections.) has NO values on it at all.That is as far as things have progressed so far.
Thank you in advance for any help you may be able to give.
Cheers.
Geoff.

[julie_m]

With some turntables, the motor does run all the time; the stop/start/reject lever (on an autochanger) or moving the tonearm to the right (on a single player) just engages the idler wheel.

Many cheap 1970s record players used to be fitted with an extra winding on the motor to supply power to the amplifier. A motor already has a stack of steel laminations with a coil of wire wrapped around; so why pay extra for a separate transformer when all you really need is another bobbin?

[Geoff 555]

Thank you very much AJS,well I never would have thought of the motor running all the time, I learn something every day.I was thinking of a micro switch and bracket etc. I will just let the thing run then. It does have the extra winding, a yellow wire going nowhere.

Cheers.
Geoff.

[Geoff 555]

Hello me again.The cartridge is now sorted. A jolly large resistor ( 150 ohms.) does the job of dropping the mains voltage to a better 220V,thank you. Now the next question please is how hot should a EL 84 get, the rest of the valves are warm but the EL84 is too hot to touch after just a few minutes. It has a paxolin (?) valve holder that looks a dark brown/black from the centre to the valve pin holes. I guess that it has been like this for a long time, I don't have the experience to tell if this is normal.
Thank you .
Cheers.
Geoff.

[Station X]

EL84s do get hot. Check that the bias on the control grid is correct. If it's too low, or has gone positive the valve will pull excess anode current. It's worth checking any screen dropper and screen decoupler too.

[Geoff 555]

Thank you, the condensers have been replaced but as regards the resistor it is just a light brown without any value or markings on it, I have yet to locate any information of any kind on this model, would it be possible to give a rough idea of what to look for please.?
Ta muchly.
Geoff.

[Station X]

Assuming the set uses cathode aka known as autobias there'll be a resistor in series with the cathode. Check the voltage across it. It should be close to the specified value of grid bais, which for an EL84 is about 7.3V.

The screen dropper resistor, if there is one. will be between HT+ and the screen grid. The anode and screen voltages of an EL84 are both specified as 250V.

[paulsherwin]

EL84s do run hot when biased for maximum class A output (as do all output valves I've ever come across). If you don't need that much volume you can increase the size of the cathode resistor somewhat which will make the EL84 run significantly cooler and last longer. You probably won't notice the reduction in maximum volume. Try increasing it by 100-300 ohms.

Paul

[Sideband]

Originally Posted by Geoff 555

Now the next question please is how hot should a EL 84 get, the rest of the valves are warm but the EL84 is too hot to touch after just a few minutes. I don't have the experience to tell if this is normal.

Geoff. Just as a general note here, all the other valves handle relatively small signals...mixer, I.F amp, detector, AF amplifier, probably none of these valves draw more than 3 - 10 mA each so the valves run fairly cool to warm. Output valves on the other hand like the EL84 have to deliver enough power to drive the loudspeaker and typically consume around 40mA (not all output valve draw as much as this while other types consume considerabley more). So therefore the anodes have to disipate more power in the form of heat.


Rich.

[Geoff 555]

hello all, many thanks for your input a new el84 seems to have settled things down, not too bad being that it was an original at 50+ years of age.
Cheers.
Geoff.

[Geoff 555]

Hello all. Gradually getting there.I am not sure where to put this so if it's not where it's should be then would you kindly move it.
This gram needs a volume control as far as I can see, but it's a type that I've never seen before. It has the usual 3 connections plus one other about half way round.When the slider reaches one end then it goes open circuit, measures 1.912 Meg. The point being if I need a new one what do I ask for please.?
There are no values, markings or make on the pot.Still can't find any info. on this thing.
Any help really appreciated, many thanks gentlemen & ladies.
Cheers.
Geoff.

[Steve_P]

You can take these controls apart and clean them. Mike Phelan did an excellent article on this which I can't find.
(Mods...?)

The three controls are the usual three. One end has come off probably. Turn the control to the end just before it stops working and measure it. This would be close enough.

The fourth lead is probably loudness. These controls are not readily available now, there is a similar one on the Pye Femnan 2.

Cheers,

Steve P.

[Nickthedentist]

Hi Geoff,

Most valve amps seem to use something like 500K log. Do you get any reading between the two ends of the track, or is it open-circuit?

The extra connection is a tap for "loudness compensation", in other words, a refinement to make the tone a bit richer at low volumes, but finding a replacement with this feature is very unlikely. Just leave it unconnected.

The best option sometimes is to try to repair the old one. Does it look easy to open up? Can we have a picture?

Nick.

P.S. Apologies to Steve, who beat me to it

[Brian R Pateman]

Originally Posted by Steve_P

You can take these controls apart and clean them. Mike Phelan did an excellent article on this which I can't find.
(Mods...?)

It's here - in the archive to Components & Circuits.

https://www.vintage-radio.net/forum/...ad.php?t=13022

Regards,

[Geoff 555]

Thank you for the information,it will be a few days until I can get to it and the solution seems to be to attempt a repair as the spindle is not a standard size anyway. It seems to be crimped together so may not want to be taken apart.That was a very interesting article Mike, up to the usual standard and very helpful.how on earth do you get such good pictures, may be you should write up a small (or indeed large) article on how it's done. Time permitting of course!!! That would be really useful.
Thank you Brian for the link.
Rechecking the resistance goes up to 1.9Meg then stops dead just before reaching the end of the track and goes open so a guess at a 2Meg pot that has broken at one end. Pity no crackles or dead spots and smooth to that point.
Once again thank you I will let you know of the progress.
Cheers.
Geoff.

[Nickthedentist]

Originally Posted by Geoff 555

It seems to be crimped together so may not want to be taken apart.

Some Philips ones have the aluminium sides "turned over" to hold the Paxolin disc at the back in place. The secret with these is to simply file away the retaining rim, then the disc and mechanism just lifts out. After repair, it can be pushed back into place, and a few tiny blobs of Araldite used to secure it.

Originally Posted by Geoff 555

Rechecking the resistance goes up to 1.9Meg then stops dead just before reaching the end of the track and goes open so a guess at a 2Meg pot that has broken at one end.

So the track is definitely open-circuit measured end-to-end? Are you sure your meter's capable of measuring over 2Megs? Some aren't!

Nick.