U2-91 clearable code

[usmjake]

Hello,

There is a sharp MX-4111N that has once every 9 months or so given a code U2-91 (which has to do with the eprom checksum) We can clear this code with sim 16

It has just done it again.

Previously, it has given code L4-50 (which has to do with fans.) It was let run for 10 days and did not duplicate that.

Is it possible that a fan problem caused damage to the eprom chip? Is clearing the code what you guys think is the best course of action?

[bilyahn]

Look at your power source. We have a color machine that does this randomly. Replaced all of the boards and the ROMs upgraded ROMs also replaced eeproms. It will work for months at a time and then suddenly it'll get 20 or 30 of these codes in a row. Unit is 150 miles from us so we don't get to baby sit it to see what is really going on. Unit always works fine while we are there. The only thing that Sharp recommends at this point is checking the line voltage to see if there are any fluctuations as this can also cause U2-91 codes. We haven't invested in a line voltage analyzer although we keep talking about it. Hope this is helpful and would very much like to know what your solution to this is.

Good luck

Bil

[ZOOTECH]

Look at your power source. We have a color machine that does this randomly. Replaced all of the boards and the ROMs upgraded ROMs also replaced eeproms. It will work for months at a time and then suddenly it'll get 20 or 30 of these codes in a row. Unit is 150 miles from us so we don't get to baby sit it to see what is really going on. Unit always works fine while we are there. The only thing that Sharp recommends at this point is checking the line voltage to see if there are any fluctuations as this can also cause U2-91 codes. We haven't invested in a line voltage analyzer although we keep talking about it. Hope this is helpful and would very much like to know what your solution to this is.

Good luck

Bil

I've got to agree with you about the dirty power causing U2 (read/write error) codes. If the PCU pwb does't fix problem, install a good power filter.

[Jkearbey]

Hello All,

I too have dealt with this very aggravating intermittent error code. The first time I had the error code was 3 years ago on a SHARP MX-503N. On that account it would reset but continue to show up weekly/monthly/ sometimes twice in a week.
I started with Firmware, next I replaced the PCU PWB, placed a power monitor on the outlet, then tried the Flash ROMs and High Voltage PWB. Last I sent in the Eeproms to SHARP and replaced those. The code didn't return for about a 2 months that time but it did return. The power monitor report didn't show anything unusual and at that point my service manager pulled the machine from the field. Until this issue the machine was an ideal account, had been in the field for about 4 years and the total meter was 700,000. It ran from PM to PM. Historically this is one of my favorite models for reliability and ease of maintenance. Machine was in a busy nurse station in a hospital/nursing home environment in Florida.

The second time I had this error code was in April 2017, when I received a service call on a MX-3100N. I first tried to reset the error with a SIM 16 trouble cancellation and updated the Firmware. The code returned about a week later so I placed a power monitor on the outlet and ordered the PCU PWB. After replacing the PCU the code didn't return for about 36 days. Once again the report came back with no unusual power spikes or ground to neutral problems. Next I replaced the Mother PWB which connects to the PCU because another technician advised that could be the problem as it was for him. I am hesitant to go any further because of my first experience even though it was a different model the other time they are similar in age and generation design. This machine has been in the filed for 6-7 years and never had anything major replaced before the PCU. Once again, this was an ideal account until the U2-91 issue. Total meter is about 450k BW & 45k Color.

If anyone has experienced this problem and found a possible solution please share, even if you didn't find a solution I would still like know your experience. Thank you for reading!

My Experience:
10 plus years on SHARP. Also work on Muratec, Kyocera and HP printers.