Philips PM3065 Scope Repair

[C-47]

After several years of occasional use the scope failed to power up, usual tracing indicated a problem after the input X2 filter caps, which were replaced and the 10v rail test point, after much searching one of the input rectification diodes was found radially cracked when de-soldered, it just fell apart, anyway replaced all 4 and powered up, then the LCD screen backlight didn't work, so removed the complete selector panel, fortunately only 2 screws retaining, bulb was blown. The part E8001 is listed as MGG 9012 at 12v 60ma, scarce, but Jaycar a local supplier had a 12v 100ma LED that was 3.1mm diameter compared to the original at 2mm, so opened out the slot on the light pipe from 2.5mm to 3.3mm and it fitted nicely for length, but the wires were radial compared to the original axial setup, so carefully drilled another 1.3mm hole on one end to take the second lead. The LCD panel had to be carefully removed by bending the 12 surround retaining clips to separate it from the circuit board so as to completely remove the light tube so no contamination got between it and the screen during fettling.
Powered up and all good, brightness appears about what was original, but time will tell if that's the case.

The original bulb is an axial element over about 14mm long and the LED is more of a spot, so had considered putting some deflection tape across the the back / top part of the light tube, but this appears not to be required. Trust the photos will provide a little more info. Alan.
 

[andy3055]

Replacing  60mA with a 100mA might blow up something.

[C-47]

Thanks, that could be correct, but limited options in that for factor, I suppose I'll have to wait and see. I searched for a direct replacement but nothing showed up, are there any possible leads.

[bd139]

Should be fine. Philips we’re very conservative with their engineering.

(Apart from plastics which are all shit  )

Btw great job. Alway wanted one of those scopes.

[C-47]

Thanks, agree on the plastic quality and the "snap" type plastic hold down / retainers.