EM34 Faulty and 'repaired' |
Michael Watterson
Redactor
IRL Artículos: 970
Esquemas: 650 Fotos: 2497 18.Nov.11 23:51 Agradecimientos totales: 5 |
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Initially the tube was completely illuminated, though dim apart from a bright part flickering shadow open and closed about 1 or 2 degrees, but very intermittent. Mostly fully closed. The AVC/AGC and drive to grid fixed (a separate story) and the opposite shadow now fully open with no signal and closing with stronger station. But the "occasionaly flickering slightly open" shadow remained fully closed. The working shadow seems to be pin 3 (sensitive? closed g = -5V) and "broken" flickery shadow (fully closed) the pin 6 (coarse closed g = -12V?).
Repair
Background If the repair is only consideration then a 6e5s (Cyrillic 6E6C) could be fitted with wiring change or adaptor. Pure "Restoration" would see the EM34 retained. However I want to listen to this set regularly. So I may fit a 6e5s (Cyrillic 6E6C) and attach the EM34 with a note and circuit changes inside the cabinet. update: It was intermittently loading HT line, so I unplugged it and between the various electrodes apart from grid (a1, a2, T, k) in every combination connected by capacitor leakage tester with a 1uF capacitor charged on its connector (nearly 360V at very low impedance for short period). The Magic Eye is now performing perfectly though dim but just usable.
"Repaired" EM34 with weak and strong signal
Este artículo fue corregido 21.Nov.11 13:46 por Michael Watterson . |