Opus 7 restore - Videokarma.org TV - Video

marloubow · #1 02-09-2014, 11:17 PM

Hi all!
It's been a couple of years since I was here last.
After my Setchel - Carlson restore, I swore off antique radios.
That is until I came across an Opus 7. It plays, but needs a bit of work...inside and out. Recap and a cab rehab.

Before I do anything I'm going to need a set of schematics. Anyone have a set? All the links I've come across are dead.

So the journey begins...

Thanks
Martin

marloubow · #2 02-11-2014, 01:06 AM

Hi all.

Well, I got the chassis out of the cabinet this evening.
Worked on mostly mechanical stuff. The dial string gears needed loosening up.
Cleaned out years of dust and grime out from the the push button assembly.
Removed the glass face...intact and in excellent shape. It cleaned up very nicely.

The EC92 tube was replaced with a 6C4. Is this a viable replacement? 6AB4 is a direct replacement.

Took a lot of photos.

Then...then I got to looking at capacitor values and locations.

I do not see how they got some of those caps in the places that they got them! I mean ...really! I read it was tight, but this is quite daunting.

Hoping for a set of schematics to show up soon. Anyone?

Will get some pics up eventually.

Martin

dieseljeep · #3 02-11-2014, 10:43 AM

Quote:

Originally Posted by marloubow

Hi all.

Well, I got the chassis out of the cabinet this evening.
Worked on mostly mechanical stuff. The dial string gears needed loosening up.
Cleaned out years of dust and grime out from the the push button assembly.
Removed the glass face...intact and in excellent shape. It cleaned up very nicely.

The EC92 tube was replaced with a 6C4. Is this a viable replacement? 6AB4 is a direct replacement.

Took a lot of photos.

Then...then I got to looking at capacitor values and locations.

I do not see how they got some of those caps in the places that they got them! I mean ...really! I read it was tight, but this is quite daunting.

Hoping for a set of schematics to show up soon. Anyone?

Will get some pics up eventually.

Martin

I swore off German radios for now! The last two I bought have push-button or selector switch issue. The plastics crumble, when the wrong kind of contact cleaner is used, which is probably any of them.
That's a Telefunken model, isn't it?
Sams had some coverage on German sets, if the were made for north American export. Usually in the form of a servicer, a one or two page folder.

dieseljeep · #4 02-11-2014, 10:57 AM

Quote:

Originally Posted by dieseljeep

I swore off German radios for now! The last two I bought have push-button or selector switch issue. The plastics crumble, when the wrong kind of contact cleaner is used, which is probably any of them.
That's a Telefunken model, isn't it?
Sams had some coverage on German sets, if the were made for north American export. Usually in the form of a servicer, a one or two page folder.

Sams shows an Opus 7, under Telefunken, 341-16.
Also, a 6c4 is a low-mu triode, where a 6ab4 is a higher-mu tube. I depends where it used. If it's used as an FM oscillator, it might not work well.

Paul Knaack · #5 02-11-2014, 03:36 PM

Hello Martin,
Here are the schematics for the Opus 7, unfortunately it is in German,
http://188.142.38.174/nvhr/Telefunken_Opus7.pdf
Heres a link to the website tht has many European radio schematics.
http://www.nvhr.nl/gfgf/schema.asp
Those are great sounding radios, also love the Grundigs and Saba's. I've got two of the Opus 6

marloubow · #6 02-11-2014, 06:32 PM

Thanks for the input gentlemen.
The German schematic's at least get me closer.
Will do some more searching for english version tonight.

Is it a good idea to replace the polystyrene caps as well as the paper?

Hope to get the caps and other parts ordered from mouser tonight.

From what I've read, the big black can is the rectifier. I'm not sure what to order as a replacement. Some help here would be welcome.

Try to get some photos up tonight.

Thanks again guys...really appreciate the help!

Martin

N8NM · #7 02-11-2014, 07:06 PM

I'm curious about the polystyrene caps, too. I haven't seen a problem with them, but don't have nearly as much experience with the european radios as I do american sets.

I have a Nordmende Kadett C in my office that I use daily. Other than the filter caps, it's all original and been extremely reliable. Of course, I probably just jinxed it...

Josef · #8 02-12-2014, 01:20 PM

Hi!

Styroflex caps in handwired tuberadios are usually reliable. I would not touch them if the radio works well after replacing the wax caps. I never had to replace a Styroflex in a radio but they can cause trouble if the connection wires become too hot when you solder them in.

Greetings Josef

marloubow · #9 02-13-2014, 01:14 AM

Well, last night I logged a total of 25 caps that will be replaced, but will double check.

Some of these proceeded to fall apart as I turned them to read there values.

I came across one that was no longer attached at one of its leads. I think I know where it goes.

I purchased a downloadable set of schematics from Samswebsite (link below) for an Opus 7. What I received was a schematic for an Opus 6.

https://www.samswebsite.com/en/photo...&submit=Search

I've emailed them, asking for the appropriate set. Will let you know what happens.

I'm really at a loss as how to work on the chassis with the bottom up.
I believe the antenna to be too fragile to allow it to bear any significant weight.

Thanks for the help!

Martin

dieseljeep · #10 02-17-2014, 12:33 PM

Quote:

Originally Posted by marloubow

Well, last night I logged a total of 25 caps that will be replaced, but will double check.

Some of these proceeded to fall apart as I turned them to read there values.

I came across one that was no longer attached at one of its leads. I think I know where it goes.

I purchased a downloadable set of schematics from Samswebsite (link below) for an Opus 7. What I received was a schematic for an Opus 6.

https://www.samswebsite.com/en/photo...&submit=Search

I've emailed them, asking for the appropriate set. Will let you know what happens.

I'm really at a loss as how to work on the chassis with the bottom up.
I believe the antenna to be too fragile to allow it to bear any significant weight.

Thanks for the help!

Martin

The chassis between the two must be similar, as they listed the Opus 6&7 on the same folder.
Regarding the ferrite antenna, if it looks like it could be damaged easily, I would disconnect and remove it.