No, replacing a regular zener diode by a ZTK type makes no sense. ZTK diodes are really very hard to get, they are very rare and much more expensive. Lets say, 10 cent for a normal ZD22 is normal, but around 1.40-2.50 Euro for a ZTK type... that's relative. I would use a ztk type if you still can get one. They are very rare meanwhile... i could

......... 5. I looked at D11 - it is located right next to the Oscillator can, below the 26V poti. In the SM, it is called a 22V regulator. The original was a ZTK22 (damaged and NLA), and I replaced it witha 22V Zener. It is measuring 21.6V. ........ A ZD22V zener diode is not a ZTK 22V diode. ZTK= Zener Temperature kompensated ZD= Zener Diode Replace

Yes, this is interesting. This would mean, that something around TR2/TR3/C16/C17 is wrong, the tuning frequency with 18,4V ist affected. Did you use electrolyth caps or plastic caps? Original they used in this time tantalum caps a lot. They are complete different to todays electrolyth caps. Tantalum is polarized, but is not in its function identical

What about the cap 1uF 0C3 ? This one is a filter for the tuning frequncy?

I would replace D5 for a better 15V zener diode, maybe temperature compensated. 13,8V or 14,3V makes a difference in FM units, since the frequency is adjusted with a voltage. A floating power supply will cause this problem. D6 could be defect and blown, this could cause this raising voltage... R45: Maybe you remember the BM7000 potis for the "no

Yes, the later version of the amp will also fit.

It could be something with the 26V and 14.3V power supply. Maybe something with the poti R45.

Das sehe ich auch sehr ähnlich. Was mich aber noch mehr stört, dass alle neuen Geräte kurzlebiger und immer schlechter dokumentiert werden. Es gibt kaum noch richtige Schaltpläne, nur noch Funktionsschemas oder wie man ganze Baugruppen austauscht. Noch schlimmer wird es, weil das Ersatzteil Lager jetzt auch in der Tschechei ist.

Replace the caps on the display board and the one behind the keyboard. The yellow marked ones are responsible for the "ir ... no contact" problem. It also makes sense to replace the big blue one on the lower board, this one is responsible for the power supply. If you find any white/grey crystals around the "+" pole, then it's

Clean and replace the grease of the gearbox. That's all. The grease on the axle of the big black gear wheel is responsible for the trouble. Open cabinet, remove the keyboard, remove the red clamps, remove wires from the drive and the slide, loosen the bolts for the front and put the mainboard into vertical position. Then you have access to the gearbox