xerox 5638 crackling sound when turning off

[Tropix]

Hi

Xerox 5638

I have a problem with 5638 when machine turnoff then crackling sound from LVPS

and on MCU PWB 24V led blinking

last fault codes is :

03-350
03-777
14-730
14-110
03-480
09-060
10-350
10-315
02-320
16-152

Machine is operating normally for some time and then appears this error with the crackling sound and so clogged

[Tropix]

Refresh

[Exok]

Re: xerox 5638 crackling sound when turning off

Problem:
LVPS relay clicks on/off rythmically, in synchronization with the loss of +24v interlocked to the IOT PWB. You can measure the 24vdc at PJ27 pin 1 on the IOT PWB and watch it cycle between 24 and 0 volts. CR16 comes on when 24v is available on the IOT PWB, and then goes off when the voltage drops to 0.
One of the typical causes of this problem is a low or cycling 12vdc on the 12v interlock circuit which is required to gate the 24v interlock circuit. But a solid 12vcd is available back to the power supply at PJ17 pin 6. (See the circuit diagram in 01-300 RAP.) This would seem to indicate that the problem is within the LVPS, but the LVPS is replaced and the problem remains.
Typically when there are problems with the 24v interlocked circuit, there are 24v related faults in history (03-480, 03-482, 06-340,09-060, 14-110, etc.). But in this case the only fault in history is a 03-365 (electrical noise), and following the 03-365 RAP does not lead to a solution.
Cause:
A defective main drive PWB. The main drive PWB is shorting 12v to the 5v line on one or both of the Xerographic CRUM communication lines. (See Figure 1 Circuit Diagram in the 03-371, 03-372 Fuser and Xerographic CRUM Communication Error RAP.) These wires should both be at +5vdc. But one (or both) of them cycles between 12vdc and 9.7vdc. (Note: the 12v to 9.7v cycling IS NOT in sychronization with the 24v to 0v cycling.)

Solution:

Measure the voltage at PJ149, pin 7 to ground, and pin 8 to ground. If the voltage at either pin is not a steady 5vdc, replace the main drive PWB, PL 4.10 or 4.15. NOTE: On some models the main drive PWB is not spared separately from the main drive module. In that case, replace the main drive module.