Info needed for 1956/7 Grundig 3028 Hi-Fi Zauberklang 6 valve AM/FM radio

[howard]

Hello,

I acquired one of these big Grundig 3028 Hi-Fi Zauberklang (transl. Charm Sound) wooden cased valve radios at the B&B at the last Wootton Bassett event. These sets were also known as the 3028 Musikgerät (transl. Music equipment) and in the USA the Grundig 3028 Majestic. I know nothing about Grundig radios so I'm hoping that someone here owns one and knows about their operation and restoration. I do have the circuit diagram for the 3028 chassis but no service data, there is an R&TVs sheet available for the Grundig 3028 W/3D Marlborough radio so does anyone know if this is another variant of this model ?

It is in excellent cosmetic condition as it sems to have always been kept under its original dust cover so there are only tiny little marks in the woodwork which will easily be disguised with some Topps scratch polish. It works on all bands too, but the cord slips on all AM wavebands so there's some work to be done there. The EM34 magic eye is dead so I've ordered a new one (gosh aren't EM34s expensive !). It has three loudspeakers, the large front driver is fine, the two side speakers (not electrostatics) are perhaps a little soft but as I've not heard one of these sets in full working order they may well be OK. It has four tone control wheels which from left to right would appear to adjust bass, lower midrange, upper midrange and treble. These do work but their effect is minor.

I like the feel of this set, it's very well built with robust controls and sounds good too. So if anyone has restored one of these and knows what faults to look out for do please let me know. Thanks.

Howard

[Steve_P]

Capacitors mostly. As always, the Audio Coupling Cap. Excellent sets though.

Cheers,

Steve P.

[Sideband]

Originally Posted by howard

The EM34 magic eye is dead so I've ordered a new one (gosh aren't EM34s expensive !).

Yes!!! However before condemning the EM34, there is usualy a high value resistor connected to the target/anode (470k - 1Mohm). This may have expired (gone high/open). Otherwise it's the valve. They don't have a grand life even if you are lucky enough to have one that works. I suppose a set of this type more or less justifies the exorbitant cost of these. However on lesser sets, it's not worth replacing them.


Rich.

[howard]

Originally Posted by Steve_P

Capacitors mostly. As always, the Audio Coupling Cap. Excellent sets though.
Cheers,
Steve P.

Hello Steve,
And thanks, yes I will most definitely be replacing any wax capacitors and the Audio Coupling Cap.

Originally Posted by Richard_Newman

Yes!!! However before condemning the EM34, there is usualy a high value resistor connected to the target/anode (470k - 1Mohm). This may have expired (gone high/open). Otherwise it's the valve. They don't have a grand life even if you are lucky enough to have one that works. I suppose a set of this type more or less justifies the exorbitant cost of these. However on lesser sets, it's not worth replacing them.
Rich.

Hello Richard,

Yes I've had one of those resistors replaced on a Philips plano set as the magic eye appeared dead, and it's now working again. If that is the problem here too it would still be worthwhile keeping a spare EM34 before they become simply too expensive ! The replacement EM34 is in fact a good as new secondhand valve so I didn't pay an exorbitant amount for it - still more than most NOS 1950s valves though ! I did consider replacing it with a top quality Soviet 6E5S valve obtainable from my Russian contact which are a lot cheaper (£7.50 each inclusive) but they only have one sector whereas the EM34 has two, and they require a certain amount of rewiring. As you say though, this is a quality set in potentially near mint condition so I think it deserves an original working EM34.

Howard

[Stewart]

These are fine sets indeed - but like most Grundig models of the day they are blighted by the Wima brand caps used within; every bit as bad as the Hunts ones being fitted to the sets made here sadly.

Replace all the brown lozenge shaped capacitors, re-string the "graphic equaliser" and attend to any tuning drive isssues (the other little quirks they seem to have) - and then settle back and enjoy!

The two mid bands of the tone control do seem to have a more subtle influence on the sound compared to the extreme bands...but do check component tolerences in this area... things were improved greatly when a few Cs and Rs were changed in on of my sets.

[Werner]

Hi Howard,

you´ve got an interessting set. The most important things are almost mentioned. If you need further information, let me know.

Werner from GRUNDIG-country (Germany)

[Tim]

Hi Howard
I did one of these a while ago. If you would like a copy of the repair report complete with photos etc. let me know by P.M.
Mine was a UK version (Marlborough).

[Mike Phelan]

Howard
I've had a few of these through my hands - the only thing I can really add is to check the adjustment and lubrication on the AM/FM tuning drive clutch mechanism driven by the FM pust-button switch; it tends to slip either way if not spot-on or greasy.

[howard]

Hello again,

Thanks all for the information.

Ron took a look at the set yesterday and the first thing that was replaced was the audio coupling capacitor as that was knackered. The set has had some work done to it already as there are some old Radiospares caps in it but most of the original WIMA capacitors are still present so I'll replace a few of those and then test them and see how well they have survived. I have a complete set of new valves for this set so I will try substituting those with the originals one at a time as they seem rather tired. The 2 x 1M ohm EM34 resistors were both fine so the replacement EM34 was fitted and it lights up OK although there's not a lot of movement yet.

The AM wire tuning cord has come off and the aerial cord is about to fall off so I that's the first job .....

Howard