Author: Provo Electronics

Repair case # 879655. 03/06/2025  Krell KAV-3250 amplifier . No sound  on one channel.

Nice amplifier. Massive power transformer,  has 3 separate  independent audio modules containing preamp, driver and output section. Nice technical design, detailed components work. All modules are interchangeable. European school schematic design and idea, strong casing , good outlook , powerful amp. Minuses –  use SMD capacitors in hard working schematic like this   is not perfect idea. Modules develops lots of heat  and destroying those capacitors fast. After 5 years they all are waste.

Troubleshooting – found shorted output transistors (6)  , cracked soldering joints on board ( output transistor legs) , all 6 SMD capacitors are dead.

Unit returned to life after  re-soldering cracked joints, 2 fuses , 6 transistors, 6 capacitors SMD.

Case 234511.    Date  02/24/2025   .  Technics SU-8600 amplifier. No sound.

Both channels not working. Protection Relay ,t click.

Capacitor c506  100 uf x 63v  in power supply section is dead. On picture new installed it is dark brown color capacitor in center ,  original was light blue.  After replacement unit is working properly. Standard deep cleaning, controls cleaning and testing performed .

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.