Power Designs 2005A Oven Repair

[BarryBreaux]

Does anyone on here have any experience repairing one of the Power Designs Ovens?

So I found that all the components in the oven have been overheated to the point that the casing around the resistors are cracked and fallen off. I suspect that the thermostat switch was not functioning correctly.

Regards,

Barry Breaux

[max.wwwang]

Did you take any photo of the crime scene?

[BarryBreaux]

Yes sir!

[BarryBreaux]

The other side.

[BarryBreaux]

The bracket that holds the thermostat broke, I think this is why it cooked my components.

[alm]

Thanks for the pictures. Those are definitely some deep-fried resistors!

[Stray Electron]

  There is at least one other thread on this forum about a tear down or a repair of the PD meters.  I think only the PD meters with the stepped dials use the ovenized temp reference.  I'm also fairly sure that there is an operators and a service manual online for the 2005 model.

[BarryBreaux]

Those toasted components all still worked somewhat. Off spec, but the power supply still worked. The controls were off by 40 mv. I also found the filter capacitor to be bad. This thing is solid!

[BarryBreaux]

I found several users who have rebuilt their oven. One user was proposing using a micro controller to improve on the temperature control. I am very interested in knowing his final design! Of course I would like to hear any success stories!

[exe]

Yeay, I'm curious too. I've a PD power supply, and those thermostat clicks are annoying. It shouldn't be too hard to implement it (I guess all it takes an opamp and a thermistor, but I'm lazy).

[floobydust]

Power Designs 2005A schematic manual https://www.barbouri.com/2018/01/13/power-designs-2005a-precision-power-source/
It looks like the TIC47 SCR 200V 0.3A which controls the heater fails short?

[max.wwwang]

I have now seen truly cooked components!