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 Post subject: Anyone recognize this Grundig?
PostPosted: Mar Tue 06, 2018 6:04 pm 
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Location: Chicago
Can't find the model# anywhere and I need to track down a schematic. Anyone have any ideas? Silver face. Not sure of the year.

Image

Image


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 Post subject: Re: Anyone recognize this Grundig?
PostPosted: Mar Tue 06, 2018 6:35 pm 
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Maybe this.


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 Post subject: Re: Anyone recognize this Grundig?
PostPosted: Mar Tue 06, 2018 6:38 pm 
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Or click on this link:

https://www.radiomuseum.org/r/grundig_hf550.html


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 Post subject: Re: Anyone recognize this Grundig?
PostPosted: Mar Tue 06, 2018 7:29 pm 
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Joined: Jan Tue 31, 2012 1:55 am
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Location: Mountains of Mourne. Ireland.
Grundig HF260 radio/amplifier...

A ten-page service manual is available at the bottom of this page...
http://www.grammofoon.com/Grundig/Grundig_KS737U.htm

translate web-page...
http://itools.com/tool/google-translate ... translator

Greg.


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 Post subject: Re: Anyone recognize this Grundig?
PostPosted: Mar Wed 07, 2018 12:28 am 
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Joined: Apr Sat 20, 2013 11:15 pm
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Thank you, Thank you, Thank you!


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 Post subject: Re: Anyone recognize this Grundig?
PostPosted: Mar Thu 15, 2018 7:01 am 
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Joined: Apr Sat 20, 2013 11:15 pm
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Location: Chicago
Hmm... Well... A couple problems. The schematic at the bottom of that page is for a CF160... I've found a partial schematic on radio museum for the HF260... They're different enough. But it's missing most of the alignment instructions. However, alignment at this point is the least of my problems.

The radio howls when the balance is turned full left or right when the volume is at zero. It is also distorted at maximum volume. Unfortunately, this radio looks like a nightmare to get into the guts of, but I'm going to start poking around with the schematic tomorrow. I'm wondering if anyone has had a similar problem with one of these that might be able to help me cut down on troubleshooting.

-Spencer


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 Post subject: Re: Anyone recognize this Grundig?
PostPosted: Mar Thu 15, 2018 7:34 am 
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Joined: Apr Sat 20, 2013 11:15 pm
Posts: 102
Location: Chicago
Found that problem rather quickly-- short between the negative speaker posts... a.k.a... operator error. smh. Still sounds a bit distorted at max volume, but I can't really crank it until tomorrow. Maybe I'll check the quiescent current first... And I have some new ps capacitors on the way from mouser.


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 Post subject: Re: Anyone recognize this Grundig?
PostPosted: Mar Thu 15, 2018 8:54 am 
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Joined: Jan Tue 31, 2012 1:55 am
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Location: Mountains of Mourne. Ireland.
This German cover page shows chassis CS 260 for the HF 260 console.
Image
A nine-page service manual for CS 260 (with alignment instructions in French... :shock: ) can be downloaded here...
https://elektrotanya.com/grundig_cs260_ ... nload.html
On the elektrotanya website ...
Wait for the ...processing... notice to change to Get Manual ←it takes a while!

There isn't a parts list, but all components are identified on the schematic/s with capacitor and resistor legends shown.


Replace all the 3V 6V 10V 25V etc. electrolytics if you can get to them.
Use 50V (or 35V) rated electrolytic capacitors→ viewtopic.php?p=2804646#p2804646
also, if you are going to keep the radio use 105° rated ones. Lol

leave the... polystyrene, ceramic and foil capacitors alone for now.

Est-ce que tu parles Français?
:) Greg.


Edit: It doesn't look too bad.
Image

Image

When disconnecting interconnecting cables or unsoldering a whole bunch of stuff, label them with masking tape flags or directly with a sharpie.
Example: tuner chassis terminal-A to amp chassis terminal-A
B to B etc.

otherwise you'll get lost when it comes to reassembly... :)
A digital camera makes a great aide-mémoire.


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 Post subject: Re: Anyone recognize this Grundig?
PostPosted: Mar Thu 15, 2018 10:22 pm 
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Joined: Apr Sat 20, 2013 11:15 pm
Posts: 102
Location: Chicago
Thanks egg, you're a gem! I pretty much just needed the clear image of the alignment points for the FM IF, and that one has it! Between that and the cs160 manual in English, I can decipher the alignment. Of course, I don't have a wobulator, smh... But I think I can interpolate to use my sweep generator and scope... I've managed before. The radio actually sounds great, I'm only concerned with the dial being very inaccurate (98.7 is at 96 on the dial). There's actually a user adjustment on the fm tuning capacitor, but it's at max just to get the dial close to right, and then the presets are way off.

I already have new high quality caps on the way from mouser, so hopefully there is some audio benefit to the recap. Otherwise it will take some digging to figure out the distortion issue.


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 Post subject: Re: Anyone recognize this Grundig?
PostPosted: Mar Fri 16, 2018 3:10 am 
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Joined: Apr Sat 20, 2013 11:15 pm
Posts: 102
Location: Chicago
I might also mention-- this thing is lightly peppered with tantalum caps. I haven't gotten through checking all of them on the schematic yet, but they seem to be appropriately de-rated (more than 50%). They're all in tuned circuits... So I may chance it and leave them alone to save having to realign the entire radio.


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