"Lid" Error Message

Straight in from the GND pad you'll see Vraw, then a square labelled VR1. In the square is a 5-pin IC held down with a bolt and nut. The pins are numbered left to right as you read the LM2575 part number on the IC, so pin 1 is nearest to the L and pin 5 is nearest to the last 5. In the picture I've attached, there's a minus sign over pin 1 and a plus sign over pin 5. Pin 3 is ground. The input is between pin 1 and pin 3, and the output is between pin 5 and pin 3. The output is VCC, and should be a nice solid 5VDC, no fluctuations on your meter's numerals (or bar graph along the bottom, if you have it). You should read zero ther if you switch your meter to read AC volts.

The input should be about 10-12VDC, but there you will see some fluctuation because it has an AC component to it.

It's a bit strange that you have 5V from VCC to GND but 4.82 at pin 10 of U20. I'm wondering if there might be some failure happening in the logic supply (VR1 to U20, etc.) It's not a huge difference and well within U20's input range, but if it's fluctuating maybe that's why there's a difference, and possibly it's causing an issue with U20 or U19.

To the left of VR1 are two electrolytic capacitors, C17 and C18.  Check to see if the tops look like the ones in the picture, and not starting to bulge up or split along the indentations.

The output reading between pins 5 and 3 is 0.00vDC. I get some meter fluctuations when I take an AC reading. Meter jumps from 0.75vAC down to zero within a few seconds. 

The input reading between pins 1 and 3 is 1.38vDC with the machine unplugged and 18.5vDC with the machine plugged in (but powered off). 

The two capacitors, C17 & C18, look identical to your photo above.

-Chris 

I'm sorry, the output is across pins 4 and 3, not 5 and 3. My mistake. Make all voltage measurements with the machine plugged in and powered on.

Jeff

The Voltage between pins 4 and 3 is indeed a solid 5vDC.

-Chris

What happens on U20 pin 10 when the lid error happens? Does the voltage suddenly drop to zero?

Jeff

What's the best way for me to check this?

Should I start the machine with the front panel removed and measure the voltage on pin 10 of U20?

Yes

At the start of a run, U20 pin 10 holds steady at 4.76vDC, the moment I get the LID error, the voltage jumps to 4.82vDC.

Also, I just noticed that the LID error has started to occur earlier and earlier in the run. The first time this happened, the machine was running at full speed for 5 minutes before I received the LID error. Now, the machine runs no more than 20 or 30 seconds before this happens.

-Chris

I'm starting to run on fumes here.

In the near left corner of the circuit board you'll see SW1. It's a component with three small switches in it. Make sure they're all off.

Other than that all I can think of is the microprocessor, but I searched earlier and they don't seem to make that particular package anymore.

Sorry, that's all I've got left.

Jeff

Jeff,

All 3 switched are off.

Thanks for your help with all of this. There seems to be an issue somewhere on the circuit board. If I can fnd another used GP8R available for parts, maybe I can convince the seller to remove the circuit board.

Aside from replacing both lid assemblies, that's the only thing left to try.

I'll update If I have anything new to add.

-Chris