Grundig 4192 Stereo Radio - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

berntd1 · 16th Dec 2009, 12:54 am

Hello,

Some news:

I have a Grundig Stereo 4192 but with BC instead of LW and also with 1 extra SW band.

The Grundig schematic I have for the Stereo 4192 / 4198 does not match my radio very well. It uses a single Output valve for the audio.

I have just bought a Photofact folder with schmatic, parts list alignment instructions for

Grundig - Majestic 4192.

It matches the radio perfectly and shows 2 EL84 valves for the outputs!

Tons of other circuitry is also different, cap values are different etc etc etc.

Did they make different versions of this radio?

Kind regards
Bernt

paulsherwin · 16th Dec 2009, 1:21 am

Quote:

Originally Posted by berntd1

Did they make different versions of this radio?

It's normal for there to be some differences between the domestic and export versions of radio designs. but not major differences like this. I suspect the European output valves used in the domestic version would have been difficult to obtain in the US, which would have been the primary export market, so the design was changed to use single ended EL84s.

Grundig made a lot of radios for export in the 50s at the luxury end of the market, so it was probably worthwhile to tailor them for specific markets.

Paul

berntd1 · 16th Dec 2009, 10:21 am

Hello,
Sounds fair but it must have been a nighmare for the parts department at Grundig.

Some examples
The german schematic shows 7 valves and the US schematic shows 10 Valves.
German detector / IF can is pn 7207-206, US is 7207-356 and so it goes on and on.

Of course it does not really matter and
I am happy to have the correct (hopefully) schematics.

I find it interesting though

Regards
Bernt

georgesgiralt · 16th Dec 2009, 10:45 am

Hello Bernt,
At that time in Germany, radio set have to pay a tax. The tax was based upon the number of valves in the set...
So they devised a 3 valves AM/FM tuner (ECC85, ECH81, EAF801) to go with a ELL80 and an ECC83 stereo amp. Then they replaced the ECC83 and ELL80 by an ECLL800. This also explain the early adoption of selenium rectifiers. Another valve spared.
Cheap sets had no magic eye, luxury one a magic eye and a plug for an optional stereo decoder based upon an ECC81.
The 3 valves tuner from Grundig is very good indeed.
As for the IF cans, the difference may lie into the AM IF frequency. European Grundigs often use 460 kHz and in the USA IF was 455 kHz. So it may have been a different tuning into the set rather than a different IF can.
I own a couple of 3397 (ECC85,ECH81,EAF801, 2xECL86, EM87 and ECC81 optional decoder) from the early 1960. When new the cost WITHOUT the stereo decoder was in the range of the cost of a today 127 cm Plasma TV .... The decoder itself was 1/4 of the radio cost ... So saving one tube could make a big difference.

berntd1 · 16th Dec 2009, 10:09 pm

Hi,

Thatnks for that. it is really interesting!

Next question:

What is the best way to remove the chassis from the case?
The speaker wires are all soldered in place.
Should I de-solder them on the speaker panel side, transformer side or try and remove the 4 speakers with the chassis somehow?

Kind regards
Bernt

georgesgiralt · 17th Dec 2009, 9:59 am

Hello Bernt,
Usually, it is easier to unsolder at the output transformer, pull the chassis out , and lengthen the wires to get into the case. Or you can plug a pair of external loudspeakers in order to test the set.
Removing the LS from the case is often very boring, so if you do not need to check them, leave them. Check the electrostatic speaker ! The foam inside gets into powder and the speaker stop working. Search on Radiomuseum.org, a German guy has posted a tutorial with a lot of picture to restore them.

JimMac53 · 17th Dec 2009, 12:47 pm

After disconnecting the speakers, I remove the entire baffle board with speakers to clean the grill cloth, which has accumulated lots of dirt over the years. I then remove the speakers from the baffle board to clean the cloth. This is just one step in the restoration process.

berntd1 · 17th Dec 2009, 10:45 pm

Hi Jim,

Do you just vacuum the cloth or wash it somehow?

Regards
Bernt

JimMac53 · 18th Dec 2009, 5:40 pm

I wash it, but have tried various ways of doing it with varying degrees of success with different radios. It depends on the material and how tightly it's bound to the baffle board. Recently I ended up warping and splitting the plywood and ended up cutting a new board and replacing the material. That was on a Grundig 3028. But the replacement looks great and everything turned out well.

If the material is easily separated from the board, I'd remove it and hand wash the material in mild laundry detergent. But there are others here with more experience, who may have some better tips. A lot depends on the material and how dirty it is. There are products such as car fabric cleaners that might do the job in situ.

dr peppers · 21st Dec 2009, 9:11 am

An external speaker is a good idea for testing, use an 8 ohm stereo speaker, the electrostatic speaker in the set can be damaged by clicks and cracks caused when testing.
I've had trouble with a grundig, it had ht on the wave selector switch, I think it switched off ht to the tuner circuit while switched to 'gram', and the switch was nearly destroyed by tracking to the chassis.

16th Dec 2009, 12:54 am	#21
berntd1 Retired Dormant Member Join Date: Dec 2009 Location: Sydney, Australia. Posts: 13	Re: Grundig 4192 Stereo Radio Hello, Some news: I have a Grundig Stereo 4192 but with BC instead of LW and also with 1 extra SW band. The Grundig schematic I have for the Stereo 4192 / 4198 does not match my radio very well. It uses a single Output valve for the audio. I have just bought a Photofact folder with schmatic, parts list alignment instructions for Grundig - Majestic 4192. It matches the radio perfectly and shows 2 EL84 valves for the outputs! Tons of other circuitry is also different, cap values are different etc etc etc. Did they make different versions of this radio? Kind regards Bernt

16th Dec 2009, 10:21 am	#23
berntd1 Retired Dormant Member Join Date: Dec 2009 Location: Sydney, Australia. Posts: 13	Re: Grundig 4192 Stereo Radio Hello, Sounds fair but it must have been a nighmare for the parts department at Grundig. Some examples The german schematic shows 7 valves and the US schematic shows 10 Valves. German detector / IF can is pn 7207-206, US is 7207-356 and so it goes on and on. Of course it does not really matter and I am happy to have the correct (hopefully) schematics. I find it interesting though Regards Bernt

16th Dec 2009, 10:45 am	#24
georgesgiralt Hexode Join Date: Jul 2008 Location: Toulouse, France Posts: 406	Re: Grundig 4192 Stereo Radio Hello Bernt, At that time in Germany, radio set have to pay a tax. The tax was based upon the number of valves in the set... So they devised a 3 valves AM/FM tuner (ECC85, ECH81, EAF801) to go with a ELL80 and an ECC83 stereo amp. Then they replaced the ECC83 and ELL80 by an ECLL800. This also explain the early adoption of selenium rectifiers. Another valve spared. Cheap sets had no magic eye, luxury one a magic eye and a plug for an optional stereo decoder based upon an ECC81. The 3 valves tuner from Grundig is very good indeed. As for the IF cans, the difference may lie into the AM IF frequency. European Grundigs often use 460 kHz and in the USA IF was 455 kHz. So it may have been a different tuning into the set rather than a different IF can. I own a couple of 3397 (ECC85,ECH81,EAF801, 2xECL86, EM87 and ECC81 optional decoder) from the early 1960. When new the cost WITHOUT the stereo decoder was in the range of the cost of a today 127 cm Plasma TV .... The decoder itself was 1/4 of the radio cost ... So saving one tube could make a big difference.

16th Dec 2009, 10:09 pm	#25
berntd1 Retired Dormant Member Join Date: Dec 2009 Location: Sydney, Australia. Posts: 13	Re: Grundig 4192 Stereo Radio Hi, Thatnks for that. it is really interesting! Next question: What is the best way to remove the chassis from the case? The speaker wires are all soldered in place. Should I de-solder them on the speaker panel side, transformer side or try and remove the 4 speakers with the chassis somehow? Kind regards Bernt

17th Dec 2009, 9:59 am	#26
georgesgiralt Hexode Join Date: Jul 2008 Location: Toulouse, France Posts: 406	Re: Grundig 4192 Stereo Radio Hello Bernt, Usually, it is easier to unsolder at the output transformer, pull the chassis out , and lengthen the wires to get into the case. Or you can plug a pair of external loudspeakers in order to test the set. Removing the LS from the case is often very boring, so if you do not need to check them, leave them. Check the electrostatic speaker ! The foam inside gets into powder and the speaker stop working. Search on Radiomuseum.org, a German guy has posted a tutorial with a lot of picture to restore them.

17th Dec 2009, 12:47 pm	#27
JimMac53 Hexode Join Date: Apr 2009 Location: Naples, Florida, USA Posts: 255	Re: Grundig 4192 Stereo Radio After disconnecting the speakers, I remove the entire baffle board with speakers to clean the grill cloth, which has accumulated lots of dirt over the years. I then remove the speakers from the baffle board to clean the cloth. This is just one step in the restoration process. __________________ Jim Mac

17th Dec 2009, 10:45 pm	#28
berntd1 Retired Dormant Member Join Date: Dec 2009 Location: Sydney, Australia. Posts: 13	Re: Grundig 4192 Stereo Radio Hi Jim, Do you just vacuum the cloth or wash it somehow? Regards Bernt

18th Dec 2009, 5:40 pm	#29
JimMac53 Hexode Join Date: Apr 2009 Location: Naples, Florida, USA Posts: 255	Re: Grundig 4192 Stereo Radio I wash it, but have tried various ways of doing it with varying degrees of success with different radios. It depends on the material and how tightly it's bound to the baffle board. Recently I ended up warping and splitting the plywood and ended up cutting a new board and replacing the material. That was on a Grundig 3028. But the replacement looks great and everything turned out well. If the material is easily separated from the board, I'd remove it and hand wash the material in mild laundry detergent. But there are others here with more experience, who may have some better tips. A lot depends on the material and how dirty it is. There are products such as car fabric cleaners that might do the job in situ. __________________ Jim Mac

21st Dec 2009, 9:11 am	#30
dr peppers Retired Dormant Member Join Date: Nov 2009 Location: Lancashire, UK. Posts: 67	Re: Grundig 4192 Stereo Radio An external speaker is a good idea for testing, use an 8 ohm stereo speaker, the electrostatic speaker in the set can be damaged by clicks and cracks caused when testing. I've had trouble with a grundig, it had ht on the wave selector switch, I think it switched off ht to the tuner circuit while switched to 'gram', and the switch was nearly destroyed by tracking to the chassis.