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Old 28th Feb 2021, 4:07 pm   #1
WaveyDipole
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Default Grundig Satellit 2000

I purchased a Satellit 2000 a while ago from a member. One of the things that was immediately evident was that the dials area was foggy. I opened up the radio today because I needed to change a couple of bulbs, hoping that the fogginess was down to a film of grime and dust on the inside, but it turns out that the outer perspex cover itself does, in fact, have a foggy appearance.

Is this a chemical change in the perspex? Is it reversible? Its difficult to tell whether this is on the inside or outside, or throughout the material, but the outside surface appears to be undamaged.

I changed the two failed bulbs and it is evident that the perspex parts on the inside are generally in good order and absolutely clear. The exception is the FM dial which has what looks like a scuff on the rear and an unsightly mark, probably from touching the surface below. I don't think there is much I can do about that.

The other question I have is, is it me, or do all Grundig transistor radios of the era sound slightly distorted? I had a Concert Boy in the 80s which I thought sounded distorted and I have heard other Grundig radios that sounded the same to my ear, as does this one. Is this down to some compromise to produce that "big grundig sound" ? The only one that I have heard that didn't sound distorted to me was the Satellit 700, but its audio characteristics seem different and cleaner. I expect that by the time the 700 was produced, they had switched from Germanium to Silicon parts in the power amp section, although I doubt that alone accounts for the cleaner audio characteristic of the Satellit 700. I have a couple of Roberts 1950's radios with germanium output transistors that sound very nice and not at all distorted like Grundigs, but naturally do not have that big Grundig sound....

Last edited by WaveyDipole; 28th Feb 2021 at 4:21 pm.
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Old 28th Feb 2021, 5:12 pm   #2
paulsherwin
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Default Re: Grundig Satellit 2000

The fogging is caused by UV damage. Sometimes you can improve things with cutting compound like T-Cut, but the damage often goes some way below the surface.

Always check the quiescent current in Grundig sets of the late 60s and 70s. The factory in Portugal seems to have had a habit of setting this to 10% of what it should be - good for battery life, but not for sound quality.
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Old 28th Feb 2021, 5:21 pm   #3
stevehertz
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Default Re: Grundig Satellit 2000

It's the same on many car headlights that use a clear plastic cover, they go yellow with UV damage. On my last car I would T-cut it off, but within six months it would be back again. But that's as a result of direct sunlight every day. On a radio, if T-cutting removes it, I'd think that it would then last for several years so long as it was not placed in sunlight.

My Satelit 650 is probably the best sounding - bar none - radio that I own. So I don't think the poor sound you're hearing is a 'Grundig thing'. Grundig prided themselves on the audio quality of their radios, especially their ability to produce deep bass.
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Old 28th Feb 2021, 5:44 pm   #4
Leon Crampin
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Default Re: Grundig Satellit 2000

My "Concert Boy" sounds good when correctly set up, with the exception of a case resonance which usually shows up on some female speech. There's room inside to stuff a whole car sponge behind the 'speaker, and leaving out the mains lead stowage lid also helps.

The audio is not quite as good as a full sized Hacker, but in every other respect, it's a far better designed and built radio.

Leon.
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Old 1st Mar 2021, 8:54 am   #5
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Default Re: Grundig Satellit 2000

I hadn't considered the possibility of UV damage. It doesn't look particularly yellow but with the fogging and under artificial light it may be hard to tell. I might have a go at t-cutting a corner to see whether it helps but I do suspect as Paul states that the damage may be well below the surface. Thank you for the explanation. Does one use ordinary auto t-cut, or is there a specific product for this?

Regarding the audio, thanks Paul. I will check the quiescent current as you suggest. The radio does generally sound pretty good and the distortion is relatively minor so although its a slight annoyance to my ear its not a major issue.

The power section seems to still have its original capacitors and from previous posts on here I gather that the smoothing can is prone to sudden failure after all these years which can take out the rectifier, so I think I will be swapping that out as a preventative measure. I haven't determined yet whether it has a selenium rectifier.

One of the faults with this unit was that the FM band was not working, however it suddenly sprung to life after the AFC switch was operated. I will clean the switches with a bit of cleaning lubricant, but since the previous owner had already done that, I am a bit puzzled. The switch is mounted separately to the chassis so it seems unlikely to be the result of mechanical pressure on the PCB.

Last edited by WaveyDipole; 1st Mar 2021 at 9:20 am.
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Old 3rd Mar 2021, 3:17 pm   #6
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Default Re: Grundig Satellit 2000

Looks like the quiescent current may have been off a bit. I have adjusted to manufacturer specs while the receiver was powered from 9V DC as indicated and it sounds a bit better.

Does anyone know where to get the light bulbs from? Two were failed and I replaced both of them with the supplied spares, but just realised that the signal meter bulb is rated 30mA rather than the 80mA as for the dial lights.
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Old 3rd Mar 2021, 3:56 pm   #7
stevehertz
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Default Re: Grundig Satellit 2000

I bought these for my 650. The guy sells 30mA and 80mA ones:

https://www.ebay.co.uk/itm/Grundig-S...UAAOSwX61ZDKEU
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Old 3rd Mar 2021, 7:19 pm   #8
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Default Re: Grundig Satellit 2000

Thank you. Those look like the ones.
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Old 11th Mar 2021, 11:24 am   #9
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Default Re: Grundig Satellit 2000

After a bit of research I found a plastic polishing kit consisting of two formulations, one for rubbing and the other for final polishing along with some suitable cloth on Amazon. This worked great on an old clock radio I had where the display had gone dull, but had no effect whatsoever on the Satellit. I suspect the fogging here is more than just a surface layer. It seems to goes much deeper, possibly all the way through the perspex so there doesn't seem to be a way to cure that.

I still have the alignment to check now but from casual observation I get the overall impression that it is quite close if not accurate on all bands. The bandspread on some of the SW bands might be a little adrift but still roughly in the right ballpark so there is nothing to be too concerned about. I will be putting the Advance 63A, refurbished only a few months ago, to good use.
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Old 11th Mar 2021, 11:44 am   #10
mark pirate
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Default Re: Grundig Satellit 2000

Quote:
I suspect the fogging here is more than just a surface layer. It seems to goes much deeper, possibly all the way through the perspex so there doesn't seem to be a way to cure that.
I had a similar problem with the the dial on my Bush TR82, T-cut usually works well, but not in this case.

I ended up wet sanding the plastic, using wet & dry paper, this took quite a while but after using finer grade paper, then cutting compound & finally T-cut.
the dial is now clear and the yellow tinge is gone.


Mark
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Old 11th Mar 2021, 3:55 pm   #11
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Default Re: Grundig Satellit 2000

I repair a lot of Grundigs including the Satellit range Distorted sound is often caused by bad electrolytic caps in the power supply and audio circuits. Even when they test OK they are often not up to par. Replace all the higher value ones, (100uF plus) and it should improve matters.
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Old 11th Mar 2021, 10:26 pm   #12
WaveyDipole
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Default Re: Grundig Satellit 2000

Quote:
Originally Posted by mark pirate View Post
Quote:
I suspect the fogging here is more than just a surface layer. It seems to goes much deeper, possibly all the way through the perspex so there doesn't seem to be a way to cure that.
I had a similar problem with the the dial on my Bush TR82, T-cut usually works well, but not in this case.

I ended up wet sanding the plastic, using wet & dry paper, this took quite a while but after using finer grade paper, then cutting compound & finally T-cut.
the dial is now clear and the yellow tinge is gone.


Mark
Mark, thanks. Sounds like I may have to persevere a lot more. Will have another look at it.

Quote:
Originally Posted by agardiner View Post
I repair a lot of Grundigs including the Satellit range Distorted sound is often caused by bad electrolytic caps in the power supply and audio circuits. Even when they test OK they are often not up to par. Replace all the higher value ones, (100uF plus) and it should improve matters.
Thanks. The ones on the power supply and output stage board have been replaced. There are a couple more axial types that are tricky to get at but I think these are lower values. At least some of the problem was down to the quiescent current level setting which was checked and adjusted as per service manual. It does sound a lot better now.

Last edited by WaveyDipole; 11th Mar 2021 at 10:38 pm.
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Old 18th Mar 2021, 12:29 pm   #13
WaveyDipole
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Default Re: Grundig Satellit 2000

When I purchased this radio I was aware that it had a problem with FM. When I first received it, FM was not working but came on suddenly when I operated the AFC switch. I cleaned the switch with switch cleaning lubricant and thought nothing more of it. Having re-assembled the radio and case yesterday, I found that the FM section was not working again. Everything was disassembled again and chassis removed from case. No amount of prodding the FM board or wiggling the switches would make FM come back on. This morning, when I powered up the radio, FM was mysteriously working again without my having done anything. It seems there is some kind of weird intermittent fault somewhere. Has anyone encountered something similar?
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Old 19th Mar 2021, 5:24 pm   #14
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Default Re: Grundig Satellit 2000

Went into the shed this morning and powered up the radio and FM was dead again. An FM signal was injected into the input to the 1st IF and I got an audio signal through the speaker so the IF chain seems OK at least. Looks like the IF frequency is around 10.7MHz. A wire was attached to the antenna input just next to the tuner and nothing was heard which eliminates the antenna switching and co-ax leading up to the tuner and narrows the problem down to the FM tuner section itself. I noted an oscillation off a particular coil yesterday and today it was absent which appears to narrow it to the LO I think. However before I could proceed further, the radio sprang into life and no amount of prodding would make any difference. It is begining to look like there is a thermal factor as the radio had been on for maybe 5-10 mins at this point. Will try again in the morning.
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Old 20th Mar 2021, 6:38 pm   #15
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Default Re: Grundig Satellit 2000

Quote:
Originally Posted by WaveyDipole View Post
Went into the shed this morning and powered up the radio and FM was dead again. An FM signal was injected into the input to the 1st IF and I got an audio signal through the speaker so the IF chain seems OK at least. Looks like the IF frequency is around 10.7MHz. A wire was attached to the antenna input just next to the tuner and nothing was heard which eliminates the antenna switching and co-ax leading up to the tuner and narrows the problem down to the FM tuner section itself. I noted an oscillation off a particular coil yesterday and today it was absent which appears to narrow it to the LO I think. However before I could proceed further, the radio sprang into life and no amount of prodding would make any difference. It is begining to look like there is a thermal factor as the radio had been on for maybe 5-10 mins at this point. Will try again in the morning.
Wavey, those round black disk decoupling caps on the IF go intermittent and short I have found on some Grundigs. Change them before you go round and round in circles. They short then go back to normal in some cases.
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Old 20th Mar 2021, 8:14 pm   #16
WaveyDipole
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Default Re: Grundig Satellit 2000

cruisinradio,

Thank you for pointing that out. I checked the voltages across ST1 and R303 and these look correct. However there was no oscillation at the junction of coil (A) and C308/C310 as there usually would be when the circuit is working, so something in that part of the circuit is evidently intermittent. Do varicap diodes have an intermittent mode of failure? If not, then that means it could be the transistor or one of the surrounding ceramic caps.

There is one black cap in the tuner section, a 47n square cap (C320?) which I think has a plastic case. As can be seen from the photo, all the other caps are small ceramic types and although there is one with a black dot on top, none are actually black bodied. Also, there are no black bodied caps in the FM IF section.

There are, however, a number of black bodied ceramic caps dotted about the AM circuits but all of the AM bands are working at present. If those caps are problematic then they might be worth replacing as a pro-active measure, but I will have a look at that once I have sorted this FM band problem.

I think I might have a go at re-flowing the joints around T2 and surrounding components on the tuner board first which I should be able to do without removing the board. If that doesn't solve it, then I guess it would indicate an intermittent component somewhere.
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Old 20th Mar 2021, 8:31 pm   #17
cruisinradio
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Default Re: Grundig Satellit 2000

I have never had a varicap go dodgy, but, easy to put a trimmer cap in place of it to see if it is dodgy, just lift one leg of the varicap off and solder a 22pF trimmer or similar to see if it starts working.
I don't trust any of those ceramic de-coupling caps in Grundig's had problems before with them.
I have also had solder flow problems, which normally look like a circular crack around the component legs. If in doubt, reflow the lot- it is quick and easy.
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Old 21st Mar 2021, 6:55 pm   #18
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Default Re: Grundig Satellit 2000

I have never seen inside a Sat 2000 before, but in your photo of the VHF tuner, I can see the top of what looks like a black rectangular ceramic capacitor.
Most likely 0.1 uF. I met hundreds of those inside the CUC series of colour TVs in both the Tuner-IFs and on the tuning boards. They adsorb moisture and become leaky. If they are on a power rail, no problem, but if on some high resistance area, expect trouble. If you check on an Avo 8 high resistance range, they usually show up, but the other two ranges show them as OK. I used to replace with a red Wima, but later Grundig started to fit identical ones, but dipped in a blue coating. They were all OK.
Never known a dodgy varicap diode, but I guess nothing is immune to failure.
Les.
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Old 23rd Mar 2021, 11:52 am   #19
WaveyDipole
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Default Re: Grundig Satellit 2000

Re-flowing most of the joints on the tuner board seems to have done the trick. It was rather difficult to tell which specific joint might have caused the problem. There were a handful that looked like they had rings around them, although I can't be sure which might have been cracked or dry internally. The simplest option was to just re-flow all of the component leg joints on that part of the board. Can mechanical stress of the tuning capacitor shaft being rotated to and fro cause joints to crack over time? Or is this just down to deterioration of the solder? There is no significant heat around that area for the problem to be heat stress related.
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