KA-6160 Shorted. SOS!

[NickDeO]

Hello AK,

I’m working on a KA-6160 receiver that needed a few new caps in the power supply. In attempting to adjust the bias after properly installing the caps, it appears that at least one of the output transistors has shorted. Now, the DBT is fully lit and nothing powers on. The only fuse I can find has not blown. Before I start tearing everything apart and testing individual components, what would you guys suggest I do? Thanks!

 

[NickDeO]

I believe the short happened on the transistor on the right side. Maybe the collector made contact with either the base or collector?
On a side note, I really prefer working on newer designs with better utilization of PCBs. This receiver is a cluster of discrete components soldered together into a bit of a tangled mess. It’s like playing Operation, but with greater consequences!

 

[avionic]

It’s like playing Operation,

Good one.. LOL

 

[avionic]

Highly recommended.. mini grabber test leads.
https://www.digikey.com/product-det...WmGslPr6m2MZOI4lfKImFmOKse1Vw7oRoCf4gQAvD_BwE

 

[NickDeO]

Highly recommended.. mini grabber test leads.
https://www.digikey.com/product-detail/en/e-z-hook/BX1W-18%20R/B/461-1052-ND/528273?utm_adgroup=Test Leads - Banana, Meter Interface&utm_source=google&utm_medium=cpc&utm_campaign=Shopping_Product_Test and Measurement_NEW&utm_term=&utm_content=Test Leads - Banana, Meter Interface&gclid=CjwKCAjw8pH3BRAXEiwA1pvMsSJW0vhsv-aRgmI1sYwAD4WmGslPr6m2MZOI4lfKImFmOKse1Vw7oRoCf4gQAvD_BwE

Thanks for the suggestion! Needless to say, they’re coming in the mail...

 

[avionic]

Remove and test the output transistors in the channel you shorted out.

 

[avionic]

Your going to need one of these sooner or later..
https://www.mouser.com/ProductDetail/Keystone-Electronics/846?qs=do/%2B0R7m72ce1CVzf8SS3w==