326
Item nr.
Wave switch carousel.
Production | USSR, 1983.
Price was 120 Rb. |
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Bands | DV (800-2000m), SV1 (305-540m), SV2 (180-310m), 25 (24-26m), 31 (30-32m), 41 (40-43m), 49 (48-51m) 52 (53-78m). |
Semi- conductors | 5x GT322B (HF, osc, mix, IF, IF), MP37 (gain control), D20 (AGC HF), D?? (det.), 4xMP41 (AF, AF, drivers), 2x GT402E (output); Indicator: KT3107D, 4x KT315, 4xLED. |
Cabinet | Plastic. Size 32x21x11 cm. Weight 2.8 kg. |
Power | 9V, Batt or external. |
Documents | Schema. |
The dial has no station names (I liked the Cyrillic on my VEF202 a lot) but wave band markings in Cyrillic and wave lengths; no frequencies. Most markings on the set are in Cyrillic, but the name Spidola is in Latin script.
The radio has a funny signal indicator with four LEDs, extincting one by one when stronger signals are received.
Obtained | 2/2011 from Andrej Smirnov. |
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Condition | 7. |
Disposed | Sold 5/2018. |
Sound sample | PLAY SOUND NS had bought Fyra trains in Italy, but the trains did not run as long as a Spidola. |
I soon suspected something wrong with the AGC circuit; this turned out to be the case, but something different from what I first thought. AGC works in two different ways. Diode D1 provides the collector voltage for T1. And detector D2 controls T6, delivering the base voltage for all HF transistors. To my surprise, under strong signals the collector of T1 would have no higher voltage than its base, and I thought this was no good. Later I was told that transistors can still process HF signals under these circumstances. But I found out that the smoothing cap C30 for the AGC was interrupted. In this way, AGC works so fast that it nulls the modulation of the signal, especially for low audio frequencies. I replaced C30 (left) and transistors T1 and T3 to reduce noise.
A week later I heard nothing but silence, but this was because I soldered T6 badly and I could repair it.