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Old 28th Mar 2023, 7:08 pm   #21
renesm1
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Default Re: Help with a Grundig KS550 that I've managed to ruin the sound of :(

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Originally Posted by Ed_Dinning View Post
Hi, a hot soldering iron placed on the screw or nuts will usually release threadlock, but may take up to a minute to work; ensure nothing else gets too hot.

If the caps are "mustards" they are good quality and probably do not need replacing.

Once you have the chassis out a good inspection may show damaged parts.
Please do not just change things in the hope it will get it working, it very seldom does. Your friend here is a multimeter, use it to take voltage readings

if there is surplus switch cleaner about it can best be removed by IPA or similar alcohols and a cotton bud. Switchcleaner will almost certainly be needed on and pushbuttons or rotary switches, followed by a lot of movement of these parts

Ed
Thanks, great advice. If I can get the chassis out, then I think the problem should reveal itself. However, whoever thought it was a good idea to glue the thing in no one else can get it back out again, has a special place in hell!!!

What were they thinking!!!!!!!
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Old 28th Mar 2023, 11:45 pm   #22
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Default Re: Help with a Grundig KS550 that I've managed to ruin the sound of :(

Don't be too critical of German engineering.

Their radiograms and radios were sold worldwide and in keeping with best practice, fixing screws and nuts would cause major problems if they became loose, hence the locking paint.

Open up many new domestic electrical units and you will find hot glue is also used to secure heavy parts, such as speakers and large components to ensure safe transit from the place of manufacture to the end user.

Looking at the restoration of the Grundig KS series, a socket set with an extension bar is seen.

A nuisance maybe, but not a cause for a formal complaint.

I'm reading your post with interest so good luck.

Chris
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Old 29th Mar 2023, 9:26 am   #23
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Default Re: Help with a Grundig KS550 that I've managed to ruin the sound of :(

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Originally Posted by renesm1 View Post

Hi, thanks for the terminology lesson - much appreciated!

Here are some pictures of the fixings with the suspect thread locker gunk. Tried to fashion some kind of small metal jimmy (jemmy) to prise apart the chassis from the cabinet to no avail.
The 2nd picture appears to still show a bolt from the cabinet underside into the chassis. Is your problem that you cannot remove the bolts due to the 'gunk' or that the chassis is somehow stuck to the cabinet? Most German sets used 4 bolts from underside into the chassis.
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Old 29th Mar 2023, 12:49 pm   #24
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Default Re: Help with a Grundig KS550 that I've managed to ruin the sound of :(

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Quote:
Originally Posted by renesm1 View Post

Hi, thanks for the terminology lesson - much appreciated!

Here are some pictures of the fixings with the suspect thread locker gunk. Tried to fashion some kind of small metal jimmy (jemmy) to prise apart the chassis from the cabinet to no avail.
The 2nd picture appears to still show a bolt from the cabinet underside into the chassis. Is your problem that you cannot remove the bolts due to the 'gunk' or that the chassis is somehow stuck to the cabinet? Most German sets used 4 bolts from underside into the chassis.
It just feels that the chassis is stuck to the cabinet. I think there are washers (or whatever they are called) underneath the chassis and I believe from trying to pry the chassis off, this is where the chassis is stuck the cabinet.

I can get a flathead screwdriver underneath the gaps between these bolts and washers, but I can't get enough purchase under the chassis to lift it off the bolts.

Not sure what else to do.

I know that if I could get the chassis off and out, I would be able to see what damage I've done to it and try to effect a repair.

Until then.....
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Old 29th Mar 2023, 12:52 pm   #25
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Default Re: Help with a Grundig KS550 that I've managed to ruin the sound of :(

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Originally Posted by simpsons View Post
Don't be too critical of German engineering.

Their radiograms and radios were sold worldwide and in keeping with best practice, fixing screws and nuts would cause major problems if they became loose, hence the locking paint.

Open up many new domestic electrical units and you will find hot glue is also used to secure heavy parts, such as speakers and large components to ensure safe transit from the place of manufacture to the end user.

Looking at the restoration of the Grundig KS series, a socket set with an extension bar is seen.

A nuisance maybe, but not a cause for a formal complaint.

I'm reading your post with interest so good luck.

Chris
I always thought gluing things together was an Apple thing to stop people from trying to fix stuff they owned!!! There isn't any nut holding the chassis in place either!

I didn't think Grundig did this as when watching various YouTube videos of people removing the chassis, it was hard but not impossible. The glue seems extremely good. I assumed that someone else had restored it and glued it back for reasons unknown. My assumptions could be wrong!
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Old 29th Mar 2023, 1:14 pm   #26
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Default Re: Help with a Grundig KS550 that I've managed to ruin the sound of :(

Grundig radios that I have serviced usually have a thick hard rubber washer between the chassis and woodwork. They are often hard to remove and maybe stuck to the wood to keep them in place when refitting the chassis.
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Old 29th Mar 2023, 1:27 pm   #27
renesm1
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Default Re: Help with a Grundig KS550 that I've managed to ruin the sound of :(

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Grundig radios that I have serviced usually have a thick hard rubber washer between the chassis and woodwork. They are often hard to remove and maybe stuck to the wood to keep them in place when refitting the chassis.
I think that is the crux of the matter. The washer is stuck to both the woodwork and the chassis. If you have any tips for removing the chassis without causing further damage, I'd love to know!

Just been at the bolts with a soldering iron and nothing has happened!!
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Old 29th Mar 2023, 1:36 pm   #28
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Default Re: Help with a Grundig KS550 that I've managed to ruin the sound of :(

Thread retaining compounds are designed to stop threads vibrating loose and it's generally fairly easy to undo them. It helps if you tighten the screw to start with and then repeatedly screw it in and out by a small amount.

Perhaps the washers are rubber which has perished and become sticky?

Can you not bend up an 'L' shaped lever, a cycle tyre lever might do, and use this to lever the chassis away from the cabinet?

Are the fixing screws fitted to tapped (threaded) holes in the chassis or did they have nuts on them?
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Old 29th Mar 2023, 1:49 pm   #29
renesm1
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Default Re: Help with a Grundig KS550 that I've managed to ruin the sound of :(

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Thread retaining compounds are designed to stop threads vibrating loose and it's generally fairly easy to undo them. It helps if you tighten the screw to start with and then repeatedly screw it in and out by a small amount.

Perhaps the washers are rubber which has perished and become sticky?

Can you not bend up an 'L' shaped lever, a cycle tyre lever might do, and use this to lever the chassis away from the cabinet?

Are the fixing screws fitted to tapped (threaded) holes in the chassis or did they have nuts on them?
Ok, so could I understand from this that those screws are screwing the chassis into the cabinet? Sounds like an odd question, but I thought they were just mounting the chassis onto the cabinet rather than screwing them in! I can't see any way of unscrewing them (can't see a helpful cross head - maybe I've missed this important detail)
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Old 29th Mar 2023, 1:59 pm   #30
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Default Re: Help with a Grundig KS550 that I've managed to ruin the sound of :(

Sorry, but you've lost me.

If the screw threads are in plain, rather then threaded, holes in the metal chassis and any nuts have been removed it should be possible to lever the chassis out.

If the holes in the chassis are threaded and the screws have no heads I've no idea how you'd get them out. I can certainly see one screw with a slot in your pictures.

EDIT.

You could try locking two nuts together on the thread and then screwing it in.
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Old 29th Mar 2023, 2:45 pm   #31
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Default Re: Help with a Grundig KS550 that I've managed to ruin the sound of :(

The chassis looks to be tapped where those screws/bolts come through, the blue stuff is probably the manufactures thread locking compound.

Mods. permitting, a completed listing for clarification only:

https://www.ebay.ie/itm/185803338471...Bk9SR9r3mdnlYQ

Lawrence.
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Old 29th Mar 2023, 2:56 pm   #32
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Default Re: Help with a Grundig KS550 that I've managed to ruin the sound of :(

That appears to have threaded bosses in the chassis which is what I would expect.

I'm still mystified by the headless screws though.
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Old 29th Mar 2023, 4:53 pm   #33
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Default Re: Help with a Grundig KS550 that I've managed to ruin the sound of :(

Looking at your photos, the chassis seems to be a long way back from the front of the cabinet. Does the panel that the chassis is mounted on come out of the cabinet (after removing some woodscrews), complete with the chassis to reveal the screw heads of the chassis mounting screws?
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Old 29th Mar 2023, 5:40 pm   #34
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Default Re: Help with a Grundig KS550 that I've managed to ruin the sound of :(

In post 10, picture. To the right of the snap is clearly a screw to undo, so possibly another to the left out of shot. Not cross headed screws but flat head.
Removing these whilst holding the chassis would no doubt release same.
You will need to look to see how the other edge is secured.
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Old 29th Mar 2023, 7:55 pm   #35
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Default Re: Help with a Grundig KS550 that I've managed to ruin the sound of :(

Although there is a YouTube video of the repair of the KS550, it isn't nearly as good as the Grundig Majestic which includes simple hints on keeping screws, cables and that for ease of disassembly and reassembly, place the unit face down so the weight of the chassis doesn't break the dial.

Anyway, enough of me, have a look at "1959 Grundig Majestic SO141Ua" on YouTube and I hope that it will answer some of your initial problems.

The video also includes dealing with noisy controls and replacing those important capacitors.

I'm sure that after watching the 3 videos and BVWS Members support you will soon have this very nice radiogram back working as intended.

Chris
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Old 31st Mar 2023, 6:53 pm   #36
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Default Re: Help with a Grundig KS550 that I've managed to ruin the sound of :(

Hi all,

Sorry for the delay in getting back to you all (was having a mental health break from the internet!)

Having let all your comments whirl around my mind for a while, I eventually realised that there were indeed a couple of screws holding the front panel on (found by the record player and the tape player drawers.

I unscrewed them and voila, the panel folds down to reveal the screws that one of you was talking about. I unscrewed them and now the chassis is all but out.

Just have to unsolder the speaker connections (making sure to photograph them first!) and I should be able to put it on a bench for further examination.

My next question is what would be likely candidates for components that I've ******** up with contact cleaner? Answers on a postcard boys and girls!!!
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Old 31st Mar 2023, 7:07 pm   #37
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Default Re: Help with a Grundig KS550 that I've managed to ruin the sound of :(

Have you actually tried it since it stopped working after the contact cleaner? I've often had things stop working after spraying, but normally they revive once the liquid cleaner has had time to evaporate.

Mike
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Old 1st Apr 2023, 4:12 pm   #38
renesm1
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Default Re: Help with a Grundig KS550 that I've managed to ruin the sound of :(

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Have you actually tried it since it stopped working after the contact cleaner? I've often had things stop working after spraying, but normally they revive once the liquid cleaner has had time to evaporate.

Mike
The thing is that it still works as far as there is an output of sound.

The issue that I've introduced by my own naivete is that since I sprayed the cleaner into the pots, the sound has become somewhat awful.

To give you an idea, I took a video https://www.facebook.com/537842564/v...03314004877536 (Apologies for linking to FAcebook!!)

I did leave it for a day after spraying to fire it back up. Done so a number of times now and still the same!

The issue is that the sound just breaks up. Not intermittently, it is like a sound effect (I mentioned dalek earlier).

If you have any ideas, do let me know!
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Old 1st Apr 2023, 6:16 pm   #39
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Default Re: Help with a Grundig KS550 that I've managed to ruin the sound of :(

Sounds as though maybe the signal from your Echo dot or whatever is too large for the input of this grundig amplifier. Have you tried it on its own radio and record player?
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Old 2nd Apr 2023, 10:40 am   #40
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Default Re: Help with a Grundig KS550 that I've managed to ruin the sound of :(

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The issue that I've introduced by my own naivete is that since I sprayed the cleaner into the pots, the sound has become somewhat awful.
Sorry to be pedantic, but you didn't spray contact cleaner into the pots. You sprayed it along the axis of their shafts and it's highly unlikely that any of it reached their tracks and wipers, especially as I believe some of the pots in this unit are co-axial types?

Now that you have access to the pots it would be a good idea to spray contact cleaner into them as it's not likely to do any harm. There's generally space around the solder tags where you can spray the cleaner into.
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