Robertson 4010 Schematic

[al2002]

Just wondering if anyone here has a copy of the circuit diagram for the Robertson 4010 power amplifier, mid 1980s vintage? If so, I'd appreciate a copy.

Thanks.

 

[sreten]

Hi,

i'd like to see it too !

/sreten.

 

[michelf]

I'm looking for the service-manuals or circuit diagram.
Thanks in advance

 

[grandschmu]

Samething, looking for schematics. I have a 4010 with a hum noise on the two sides. Maybe the rectifier capacitors? Or an ground open resistor? Have an idea?

 

[tony.garner]

Have a Robertson 4010 amp sweet and powerful. Would also like copy of schema

 

[djk]

I have repaired them without the schematics, they are a cross-coupled dual-diff input, fully complimentary from input to output.

I have had to dig the potting compound out of the input modules to repair them (modules being unavailable).

A solder joint in the potted module had failed, the parts themselves were OK.

Use a 75W lightbulb tester in series with the power cord for a few days before buttoning up for good. I had a potted module fail about four hours after replacing the outputs and drivers, the lightbulb saved the new parts, allowing me to find the potted module defect.

 

[tony.garner]

So what did you find in potted module. I think transistor and resistor but do you have the values/types

 

[djk]

One TO-220 transistor, and a 1/4W resistor (values not remembered),

The problem was just a bad solder joint.

It was not too bad to dig out the potting compound, and the parts values were easy to read. An easy (if time consuming) repair.