DP 770 upper lift sensor working backwards

**Kidaver** · 04-01-2016

So this one has been an interesting one. I have a DP 770 on a TA 4500i where the upper limit sensor for the lift is working backwards. It is changing state but in reverse. If you barely lift the feed system to block the sensor and press start the tray will lift and pull paper. I have replaced the sensor, wiring harness, DP main board, and the relay board. I've talked to Kyo tech support 4 times and each tech I talk to all says the same thing. "Wow that's really weird". Should hear from Kyo rep to come out soon but like to hear you guy's thoughts on this one.

**blackcat4866** · 04-02-2016

The way I see it you've got three possibilities:

1) SDULS SD upper limit sensor (unlikely, if it's changing state it's probably working properly).

2) SDMPB Side Deck Controller
YC5-14 1.2vdc supply
YC5-15 ground
YC5-16 signal 0/3.3vdc ON/OFF
YC13-1 Serial Communication to Engine PWB
YC13-2 Serial Communication to Engine PWB
YC13-3 Clock Signal to Engine PWB
It's possible that the side deck controller is reading the sensor incorrectly, or reading it correctly but incorrectly translating the serial data to the engine PWB.

3) EPWB Engine PWB
YC19-A4 Serial Communication from SDMPB
YC19-A2 Serial Communication from SDMPB
YC19-A1 Clock Signal from SDMPB
The engine PWB may be incorrectly reading the serial data from the SD controller.

I think I would start with reading SDULS at SDMPB YC5-14, 15, 16. If you can see it change state from 0 to 3.3vdc then ... I would pin out the connections between the SDMPB YC13 and the EPWB YC19. Then I would swap the side deck to another Alphard. If the problem follows the deck I would change SDMPB. If the problem follows the MFP I would change E PWB. Logical?

=^..^=

**Santander** · 04-02-2016

The problem is the holder for the feed rollers, P/n 303JX07030. It cracks and when it is raised in the feed process it raises out of the sensor range. the specific problem is the stop on the back side of the holder breaks off or the frame cracks and allows the holder to rise to far causing the problem. A quick field fix is to add 1/4 inch of black tape to the bottom of the flag the sensor sees, but to fix it permanently replace the holder.

**tmaged** · 04-03-2016

The only thing I can offer is, we kept getting tray down errors on an 6551ci DP. We replaced the up & down sensors, motor & board and they continued. Our rep suggested that we replace ALL sensors in the document processor. Said they had a finisher with odd problems that did that. It ended up correcting ours.

**Kidaver** · 04-04-2016

Originally Posted by Santander

The problem is the holder for the feed rollers, P/n 303JX07030. It cracks and when it is raised in the feed process it raises out of the sensor range. the specific problem is the stop on the back side of the holder breaks off or the frame cracks and allows the holder to rise to far causing the problem. A quick field fix is to add 1/4 inch of black tape to the bottom of the flag the sensor sees, but to fix it permanently replace the holder.

This here is close to what is actually wrong with it. We emailed our regional tech rep and he sent me the solutions. there is a tab on the front of the feed assembly that breaks causing the assembly to drop about 1/4 in. If you don't know what to look for you can easily miss this. And just to think a few weeks ago here I was telling our 2 rookies that sometimes we look to far into some of the simplest fixes and here I got caught in one. I know we all had it happen. Tho I spoke with Kyo tech support 3 or 4 times and no one ever said to look for this but it was the first thing the tech rep suggested.

**ss12** · 04-05-2016

Originally Posted by Kidaver

This here is close to what is actually wrong with it. We emailed our regional tech rep and he sent me the solutions. there is a tab on the front of the feed assembly that breaks causing the assembly to drop about 1/4 in. If you don't know what to look for you can easily miss this. And just to think a few weeks ago here I was telling our 2 rookies that sometimes we look to far into some of the simplest fixes and here I got caught in one. I know we all had it happen. Tho I spoke with Kyo tech support 3 or 4 times and no one ever said to look for this but it was the first thing the tech rep suggested.

Ive had this happen a number of times.My fix is to apply a cable tie around the housing with the tab in the same place as the one that breaks.not been back to one since for this issue

**blackcat4866** · 04-06-2016

Originally Posted by ss12

Ive had this happen a number of times.My fix is to apply a cable tie around the housing with the tab in the same place as the one that breaks.not been back to one since for this issue

Picture please? =^..^=

**Tonerkiller** · 04-06-2016

Originally Posted by Kidaver

This here is close to what is actually wrong with it. We emailed our regional tech rep and he sent me the solutions. there is a tab on the front of the feed assembly that breaks causing the assembly to drop about 1/4 in. If you don't know what to look for you can easily miss this. And just to think a few weeks ago here I was telling our 2 rookies that sometimes we look to far into some of the simplest fixes and here I got caught in one. I know we all had it happen. Tho I spoke with Kyo tech support 3 or 4 times and no one ever said to look for this but it was the first thing the tech rep suggested.

This is a common problem

**Kidaver** · 04-06-2016

I had never seen it before, but when I emailed the regional tech rep he had and told me to look for that right away. What annoyed me was I had talk to tech support 3 or 4 times and they had not mentioned that at all.