Re: [CAD_CAM_EDM_DRO] Westamp - PWM Servo Amp

bdoherty01@... wrote:

> Hi,
> I have a Westamp PWM servo amp model no. 30060-3 ,(1981),with a
> faulty output stage.Details:
> Supply voltage: 100vdc
> Signal :+/- 10v
> Bias :15-0-15vdc
> Max output:20amp
> Cont output:10amp
> Motor HP : 1.1
> The output bridge uses four T03 packaged NPN silicon transistors
> which appear to have an internal 100r resistor across base-emitter
> and an internal diode across emitter-collector ,part
> no:29782w /c38123102.I am unable to locate replacements and both
> UK/US agents refuse to supply drawings or spares and quote $850.00
> and 30 working days for repairs!
> Can anyone suggest a replacement component, possibly with the
> resistor and diode mounted externally ? All help is greatly
> appreciated,

I was working with another guy who had a similar problem. I don't think
he ever got it fixed. I think we figured out the transistors were similar
to MJE13007 or thereabouts, but I don't know if we ever figured out
what to do about the driver chip. The transistors are almost certainly
Darlington type.

Jon