Korg Stage Echo se300 repair

[samsp]

Hi everyone,

I have purchased two stage echo se 300 recently and one of them is still not working properly.

At first it was not working at all and slowly it's i m getting some signal back.

First of all the erase head was not aligned with the tape so it was not not erasing at all. I have fixed that and now it's ok.

Then i started aligning the other head. For that i sent a white noise in the input and plug a jack in the effect (wet signal) output. Then i monitored with a spectral analyser as i was turning the screws for each heads. It s not conventionnal but it seems to work.

Heads have been demagnetized and cleaned.

Now my problem is with the feedback. I only get one repeat when feedback pot is closed and hardly get more repeats when it s fully open. Maybe one repeat and a half.

Does anyone could help me troubleshoot the feedback problem i have ?

There are three trimpots inside this beast.

One between the erase and record head (i think it s a capacitor)
Two on the main pcb (white vr301) (green cl301)

Do you know what they do in the circuit ?

Thanks for your help.

 

[MAAC0]

That capacitor trimmer is perhaps the erase HF frequency. The others could be for record / playback level and Bias.