560
Item nr.


Grundig Satellit 2100 World receiver

Big portable with small fault


Data for Grundig Satellit 2100
ProductionGermany, 1977.
BandsLW, MW, 2xTB, 8xSW, 8x Band spread, FM.
CabinetPlastic.
PowerAC, Batt.
DocumentsService Docs.

The Design

For a general description, see my other Satellit 2100. Though electrically identical, the 2100 exists in various colors and details on the outside. This picture shows Ellen's radio on the left and my own on the right. Ellen's is in very good shape generally, but unfortunately, the transparent sheet in front of the three dials has become a bit milky. You see that Ellen has black pushbuttons and metallic rotaries, while mine has metallic pushbuttons and knobs with a black center. The advertisement on the right shows a 2100 with the black rotary knobs, and black pushbuttons, and also black edges on top and bottom of the front plate. I've seen another 2100 with the milky dial glass, and that was the same version as Ellen's. So maybe only this type (with the larger rectangle grill) goes the milky way.

ObtainedWas never mine, repaired for Ellen; sn=110567, 2/2022.
Condition8.

This Object

Ellen approached me to repair the Satellit 2100 for her. One problem was that the band switched didn't operate, the other that the radio was completely silent.

The switch problem was not new to me, I had repaired defective switches before. The switch levers brittle, and then the springs underneath the buttons don't push them upwards anymore. The solution is to drill a small hole through the lever and push a pin through it, as can be seen on the photo left. New to me was that some knobs have an extra detail: three of the knobs are self-releasing (Treble speaker, power, and antenna). These three have an extra piece of metal onder the spring, and the spring needs a little bit more space to allow this metal to move. So, for those three knobs, if they need repair, drill the hole a little higher!

When you open a Satellit 2100 (or 2000) and pull the chassis, it looks like the picture on the right. It is a quite complicated combination of about six circuit boards, not all very easy to reach. For anything more than a simple inspection, unsolder the leads to the loudspeakers, to get some more freedom.

In this case, the radio was completely silent and I soon started to suspect the power supply. Normally, even with volume completely down, the S-meter will still react to tuning and testify the activity of the selected tuner, but here there was no S-meter reaction at all. Also, there was no signal on the line out and the tape input didn't work, either. It took me some time (and help from the transistorforum) to find out how the power supply worked, but after that, the repair was quite simple. The thing to understand is that the LF part (called NF Platte in the docs) works with positive voltage relative to ground, and this voltage directly supplies the LF amplifier (from transistor T21). But also, the NF Platte has a voltage regulator, supplying 9V for the HF circuits (and the audio pre-amp T21). What confused me, was that this +9V is actually the ground of the HF parts, and indicated with a ground symbol. So the HF circuits work with negative power relative to ground. The switches that choose the desired tuner are connected to the minus of the NF Platte, which is negative -9V supply for the tuners.

The most sensible thing to do then, is to follow voltage from the stabilizer circuit and see where it ends. I found +9 (relative to the mass of the NF Platte) on the basis of T27, so the stabilizer worked fine. Also switch contacts b5, b6, c and the dial light had +9V. And on the one end of resistor R410 I measured +9, but on the other side (top of C450) there was nothing. Resistance measurements indicated that R410 was OK, but C450 was shorted. I removed C450 and the radio worked! The importance of C450 shouldn't be overestimated, after all it follows a stabilizer. But still, Grundig included it for a reason I presume, so I replaced it with a new 1000uF elco (photo). R410 had been overloaded a bit with 1W, but it still looked and measured good.


Part of Gerard's Radio Corner.
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