Makeover to a Philips Colette (LD562AB) AM/FM 10 valve portable radio c.1956

[Robert Darwent]

Introduction

The 'Colette' LD562AB is a top-of-the-range AM/FM valve mains/battery portable first released in Germany by Philips in 1956, and a year later in The Netherlands as the 'Clipper' L5X62AB.

The set offers LW, MW, SW (bandspread 31 to 49 metres) and VHF (87.5 to 100 MHz) with three IF stages using DF97's. The two IF's used are 10.7 MHz and 460 kHz. It employs 10 valves altogether, all 25mA minature B7G types.

The circuit uses a push-pull output stage which provides excellent quality audio from a double coned loudspeaker. An odd feature is the use of a DM71 'magic eye' as a phase splitter for the output stage. This valve is not used as a tuning indicator, but just lights up to indicate the set is switched on!

There is a separate oscillator valve on AM which also provides the bias for the output stage from its grid leak. This valve still has to continue to operate when VHF is selected to provide bias, and so is shunted on to 1250 kHz to keep it out of the way whilst this band is in use.

The LT circuit is unusual in that a Nicad cell, called a DEAC, is permanently wired into the LT supply to provide voltage stabilisation and smoothing. Without it the LT can easily rise high enough to burn out all of the valve filaments!

A front panel push button is provided, marked 'Laden', to put the Nicad on charge whilst the set is switched off. On this postion there is a 12V 3W bulb in series with the cell to limit current and to remind you that charging is taking place.

The set is powered on batteries by a pair of 1.5V D-cells for the LT, together with a 90V battery for the HT. The D-cells are connected in parallel with the Nicad, and the set is switched over to battery by inserting the 2-pin mains plug into an internal socket on the power supply board.

An 'economy' switch is also provided which is operated by pulling out the volume control, this switches off half of each of the two DL96 output valve filaments, so prolonging the LT battery life when required.


As Acquired

The five images below show the condition of the set when it first arrived. My initial impressions were quite favourable, but closer scrutiny revealed a number of problems. This set was going to prove to be a no-quick fix, both cosmetically and electrically!

The front and back of the case are made from bakelite, the middle section being wood. Most noticeable was a large crack in the bakelite above the tuning dial which had split the cloth covering. This area revealed the cloth to be paper thin and extremely brittle with age, repairing the crack without tearing the cloth further was going to be very difficult. Further examination showed many smaller tears, especially underneath and on the curved corners of the case.

The metal grille on the front was coming away, most obvious in the top left corner. Several of its fixing points were broken and there was no easy way of securing it with glue due to the tension in the metal 'springing' the grille away from the surface of the case.

The bakelite around the tuning dial and the recessed areas of the grille were covered in a reddish brown paint. This had become quite worn in places and was readily flaking off.

Internally, the DEAC nicad together with all the battery holders and straps were missing. Worse still someone had rigged up an 'Heath Robinson' affair of a LT voltage regulator on a piece of wood to replace the nicad. In so doing he/she had disturbed just about every wire going to the main chassis from the power supply board!

As expected my initial repair attempts to the case only made matters worse and I quickly decided that if the set was ever to look presentable again then a complete recover of the cloth was going to be necessary.....

[Robert Darwent]

Case Restoration

Whilst searching for a suitable replacement cloth I came across some PVC grey and black imitation snakeskin material with a cloth backing. Since quite a few other German portables of the 1950's had snakeskin coverings, several models by Akkord for example, I decided it would be acceptable for the 'Colette' too. To be honest I wasn't too keen on keeping the original red and cream colour scheme. To my eyes it just didn't look right.

So I set about completely dismantling the case and removed all fixings and trims. I removed the red paint from the grille by immersing it in a shallow tray containing a Nitromors type paint stripper. Afterwards the grille was washed clean in warm water and dried. It along with the other brass trims were then cleaned with foam cleanser, polished with Brasso wadding, then given a spray coat of acrylic lacquer to prevent further tarnish.

I removed all the old cloth from the case in about 10 minutes, it was that brittle, and just came away in large pieces with little effort. I was left with areas of hard glue on the two bakelite sections which I removed by painting on more paint stripper then washing off after it had softened and lifted the glue. Paint stripper was similarly used to remove the red paint on the bakelite around the the tuning dial, which was then polished with Brasso.

To replace the broken metal fixings on the grille I soldered several small pieces of thick guage copper wire in their place which secured it firmly once again to the bakelite front. Also at this point I painted over the original red areas inside the case middle with a matt black finish.

I cut suitable sized pieces from the snakeskin material I had obtained, taking care to match the pattern on the front and back sections. To fix the new cloth I used Evo-Stik Flooring Adhesive. This has the advantage of staying 'wet' for 15 to 20 minutes, giving sufficient time to apply with a small brush and to get the cloth positioned correctly on the case sections. It is also water based and so any excess can be easily removed with a damp sponge.

The two bakelite sections have curved corners, so it was necessary to stretch the cloth at these points in order to remove any wrinkling. I found the best approach was to apply a liberal coating of adhesive to the bakelite, position over the laid out cloth, wrap the cloth over the edges of the case and secure temporarily with spring type wooden clothes pegs. I was then able to smooth out any bubbles of air trapped underneath and gradually work my way around the edge replacing the pegs with strips of tensioned masking tape. The various sections were then set aside to dry.

After 12 hours or so the adhesive had dried enough so that all the masking tape could be removed. I was then able to trim any excess material and secure any minor areas that had not stuck down correctly with superglue. The curved corners were treated similarly, and I found re-tensioning here as necessary, then glueing down with superglue provided a permanent wrinkle free result.....

[Robert Darwent]

Circuit Restoration

As previously mentioned, virtually every one of the dozen or so wires going between the main chassis and power supply board had been disturbed. For some unfathomable reason someone had reversed what was left of the HT battery leads, so that red was chassis, and black +ve! Other wires were left disconnected, and yet others going to where they shouldn't be going, or missing entirely. It all took a long time to trace and sort out, especially when you look at the sheer density of the wiring involved, but gradually I got things returned to how they should have been originally.

Eventually I was at the point when I could safely apply power for the first time. I connected up 90V and 1.5V bench supplies and switched on. I was greeted by the chassis working and producing excellent quality audio on the VHF position! However the MW band was dead, which I hoped was just down to dirty switch contacts, which it later proved to be. On all the other bands the set appeared to be working well, but an ammeter in the HT supply showed it to be drawing around 37mA instead of the expected 12 to 15mA stated in the schematics. So something was definitely amiss somewhere!

I began the job of re-capping, which isn't a quick or easy task with this set. There are around 90 capacitors in total, and at least a few dozen are paper/wax types along with perhaps another half dozen electrolytics! Again the density of the wiring under the chassis made for slow progress, but I eventually removed all the suspect capacitors and replaced them with either new yellow 630V polypropylene types, or correctly rated electrolytics, as shown in the images below. In total I replaced nearly 40 capacitors. All the paper/wax types removed had gone high in value and were leaking. The electrolytics tested OK but I replaced them anyhow for good measure.

Several times, after changing a group of capacitors, I checked the HT current again and it was coming down towards the stated value. However when re-capping was complete the current was still too high at around 19 to 22 mA despite everything obvious having been replaced. Eventually after much 'head-scratching' I tried replacing the DF97 being employed as the oscillator valve. Immediately HT current comsumption dropped to 9 to 11 mA. With hindsight I should have suspected it sooner, since just about every other component connected with the bias line to the ouput stage had been changed. But at least the problem had been solved!

The first three images below show views of the main chassis and its high component/wiring density. The fourth image shows the red 'Laden' charging indicator, and the last image the DM71 'magic-eye' used as a power indicator in this design.....

[Robert Darwent]

Batteries and the DEAC nicad

In keeping with my usual practice when restoring portable sets, I like to construct an authentic set of reproduction batteries and covers to show the set operating as it was originally intended. The following images show how the batteries were installed in the case. I managed to obtain original battery holders and straps from a related German AM/FM valve portable that had a too badly damaged case. Fortunately they were identical to the missing parts I needed to complete the 'Colette'. The reproduction DEAC D6 contains a modern 1.2V nicad D-cell in a holder. The other two D-cells have been furnished with Pertrix No.231 covers of the period. The HT battery is a 90V Pertrix No.78 battery housing a chain of 10 x PP3 batteries in series.....

[Robert Darwent]

Finished Result

The five images below show the set reassembled and fully restored. I am very pleased with how the new cloth covering has turned out, it has more than exceeded my modes expectations. Whilst not keeping to the original colour scheme, I hope others will agree that it is still in keeping with other snakeskin covered sets of its 1950's vintage.

At this point I should like to acknowledge and thank the assistance of several forum members with this restoration; Howard for providing me with copies of the schematics for the set, Edward (igranic) who's helpful advice on circuit operation and fault tracing is always invaluable, Paul (Paul_RK) who sent me a copy of the Radiophile article regarding the 'Colette', Bill (batterymaker1) who provided me with the Pertrix graphics upon which my re-worked battery covers were based. Thanks guys!

[mark pirate]

Fantastic job Robert, i love what you have done with the case, it looks brilliant An unusual set, that has had the make over it deserves

Mark

[batterymaker1]

To quote a recent movie character, that snakeskin is "dead sexy"....

Beautiful restoration, reminds me of my Annette.

Such a waste for Philips to use that tuning indicator for a glorified pilot light.

[julie_m]

That's a fantastic job! It really is a lovely-looking set -- and it must have cost somebody a fair amount in its day, too.

The "creative" use of that indicator tube is just odd, though! Does it do anything at all, visually?

[jjl]

Originally Posted by rrdmpb

Introduction
An odd feature is the use of a DM71 'magic eye' as a phase splitter for the output stage. This valve is not used as a tuning indicator, but just lights up to indicate the set is switched on!

There is a separate oscillator valve on AM which also provides the bias for the output stage from its grid leak. This valve still has to continue to operate when VHF is selected to provide bias, and so is shunted on to 1250 kHz to keep it out of the way whilst this band is in use.

The LT circuit is unusual in that a Nicad cell, called a DEAC, is permanently wired into the LT supply to provide voltage stabilisation and smoothing. Without it the LT can easily rise high enough to burn out all of the valve filaments!

Wow , there's a set of strange circuit designs.
I thought that fiendishly complicated dial drives with bits that belong on bicycle brakes, positive feedback tone controls, bonkers bi-ampli output stages using valves that should be confined to a '50s telly line output cage, 800 ohm speakers and chassis-less sets that seem to have been assembled with the aid of a shovel were weird enough.

Perhaps the Philips company motto could have been

"Putting wacky ideas into volume production".

Just a thought.

John

[Colin]

Congratulations on a wonderful restoration. You've set us all a very high standard to aspire to Robert!

The snakeskin looks great ... but does it rattle?

[jjl]

Robert

I hope my previous comments weren't too flippant; there's just something about Philips...

The re-covered case of your set looks fantastic.
That under-chassis view looks pretty hairy, it must have been a daunting task replacing all of those caps amongst that lot.
Congratulations on restoring this interesting set to such a marvellous condition.

John

[batterymaker1]

Hey, at least it doesn't have a clutch tuning drive....

I think I heard it remarked from a European collector this way about servicing radios:

"There's Philips....and there's everyone else."

[igranic]

Robert,

Absolutely exemplary!! Your painstaking work on these challenging radios is to be much admired.

Whilst the snakeskin finish may not be 100% authentic, there were occasions when the designers went for bland safety and produced something which did not excite; I believe you made exactly the right choice.

I do hope I can hear it in action in the not too distant future.

Edward

[chipp1968]

Very impressive . talk about ugly duckling /swans etc amazing transformation

[Robert Darwent]

Originally Posted by ajs_derby

That's a fantastic job! It really is a lovely-looking set

Originally Posted by Colin

Congratulations on a wonderful restoration. You've set us all a very high standard to aspire to Robert!

Originally Posted by jjl

Congratulations on restoring this interesting set to such a marvellous condition.

Originally Posted by igranic

Absolutely exemplary!! Your painstaking work on these challenging radios is to be much admired.

Originally Posted by chipp1968

Very impressive . talk about ugly duckling /swans etc amazing transformation

Well, judging by all your positive comments it seems I made the right choice with the snakeskin material for recovering this set!

Many thanks for all the kind words of praise. It really does makes it all worth while, much appreciated!

Regards

[Robert Darwent]

Originally Posted by mark pirate

Fantastic job Robert, i love what you have done with the case, it looks brilliant

Originally Posted by batterymaker1

To quote a recent movie character, that snakeskin is "dead sexy"....

Sorry Guys, missed you out the first time around! Many thanks for your kind compliments too!

Originally Posted by jjl

Wow , there's a set of strange circuit designs... ...Perhaps the Philips company motto could have been; "Putting wacky ideas into volume production".

I think we all share a similar opinion about Philips obtuse way of doing certain things. But regarding the use of DEAC nicad's, I thought you might like to know that they weren't just confined to Philips models of the period.

I think I'm correct in saying that just about all the major German manufacturers of 1950's valve radio portables incorporated the nicad idea into their models.

I have in my collection sets by Akkord, Grundig, Schaub, and Telefunken which all have DEAC's as part of the LT supply. So actually it was quite common in Europe at the time, especially amongst sets produced for the German speaking market.

Originally Posted by batterymaker1

Such a waste for Philips to use that tuning indicator for a glorified pilot light.

Originally Posted by ajs_derby

The "creative" use of that indicator tube is just odd, though! Does it do anything at all, visually?

Regarding the DM71 'magic-eye' being strangely employed just as a power-on indicator. I read somewhere that late on in the production of the 'Colette' Philips discovered that the audio quality of the set fell short of expectations. So to save the day they got around the problem by rewiring the DM71 as a phase splitter. This cured the audio issue but prevented the DM71 being used as a tuning indicator as originally intended.

Incidentally on the forum pages of 'radiomuseum.org' there is a detailed modification to incorporate a DC90 valve into the 'Colette' as the phase splitter, so allowing the DM71 to be reconnected as a working tuning indicator. The modification apparently works very well, but I decided just to restore my set to the original specifications. Something I may attempt at a later date though.

Regards

[Tim]

WOW!

[Robert Darwent]

Originally Posted by Tim

WOW!

I can't ask for more than that reaction Tim, thank you!


Below I've included further images of the covers and internals of the reproduction batteries I constructed for the set.

The last image is of an electrical equivalent that can be used to substitute for the DEAC cell. The two diodes limit the LT and ensure that it cannot rise high enough to cause damage to the valve filaments whilst the set is operating from mains power.

I've managed to incorporate these components into the small cavity above the D-cell holder inside the card case of the reproduction DEAC, a tight fit but there was just sufficient space to do so.

Regards

[ajs37]

simply stunning Robert - well done!

[geofy]

Excellent work, the original nicad is unusual and could start a new thread on the origins of rechargable cells!

Geof