Month: March 2025

01/18/2025  .Unusual repair case #189674 . Marantz 2270 .  No AM band signal , no balance control.

Unit after  full service in our shop. After customer pick up unit and tried to use it  – no AM ,  BALANCE  left/right not working. During service visit in customer home found – not original screws used for mounting wooden case . New screws what customer used for mounting wooden case on this unit a little longer then original and touching components inside. Difference in length was not big –  just 5-6 mm. , but it makes a big difference. Front screws for wooden case need to be same as original. Unexpected issue.

We are not fixing audio today.  I upgrade my old friend Dewault 920  . This hard working  guy  was in service with me from 2010 .  Got good reputation and perfect resume .   As you know this tool works for electrical jobs and small projects and use not powerfull NI-MH battery  7,2 Volt.  After 5- 9  month  of work you have to buy new battery. In this case we will transfer  it to lithium 7.4 volt battery . We use two 18650 lithium elements in series. Gentle soldering requaired. Create new charge port and drop new batteries in old plastic shell .   DO NOT USE OLD CHARGER !!!!     It will damage new Lithium battery.

In my case i used simple audio RCA plug as charging port. Charger we will use 8.4 volt  1-2 Amp for lithium batteries only.   8.4 volt only with protection and current control . Will do update how my upgrade process  goes.

Case 432200. 12/27/2024. Sansui AU-719. Increasing volume leads to cut left channel in half.
Nice amplifier. Build to last. Problem acting as bad volume pot.
After detailed diagnostic found contacts oxidation on speaker protection relay. Relay replacement solved this problem.