560 is possesed

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Re: 560 is possesed

Postby Jaykob » December 17th, 2012, 1:23 pm

Thanks for your help Gordon and sorry for the late reply!
I got a replacement main_PCA from ebay and the Roomba is alive again now :)
I'll have one more look inspecting your last hint regarding VBAT and R138 to save the old PCA from the trash...
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Re: 560 is possesed

Postby Kelad » September 8th, 2016, 8:31 am

Hi Guys
i have an identical issue as reported by the OP in this post, however it is with a 780.

1. The 780 can charge happily for 11 hrs, runs cleaning mission ok and then on charge it reboots within 10 mins of charge
2. It can be off charge and just sitting there and it can reboot.
3. I put it on charge (GREEN led ON), at 930pm, go to bed and it reboots several times during the night (charge log attached - you will see the reboots).

From the log you will see the temp gets to 51 deg, which is high compared to my other robot. Also the current is '-8'.

I ran BIT 22-28 and all passed.

I have tried:
- good known battery
- different power supply/base station
- charged from side
- pulled battery contacts out

Do you think the comments in this post regarding the 560 are valid for the 780? i dont think the OP ever found a fix.

Thanks all.
Attachments
ray pass.txt
BITs results
(1.33 KiB) Downloaded 14 times
780 charge log.txt
sample of charge log
(7.57 KiB) Downloaded 11 times
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Re: 560 is possesed

Postby a1robotrepair » September 8th, 2016, 11:34 am

I had the same problem on 2 560 PCAs. When the battery was fully charged, the clean light should turn green, the bot reset and started the charging procedure again, clean led flashing orange.
My problem in both cases was D46 open.
http://www.robotreviews.com/chat/download/file.php?id=8537&mode=view
This drawing is neither complete nor entirely correct.
I think the components on a 780 are labeled the same, I'm hoping to get a board to trace someday, so far I have been able to fix all the failed 700 boards, none have come my way that have been drowned.
Roses are red Violets are blue Poems are hard Flowers and Chocolate
http://www.daycounter.com/Calculators/
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Re: 560 is possesed

Postby Kelad » September 10th, 2016, 8:51 pm

Thanks a1robotrepair, I measure D46 in board on my 780. Its 0.187 fwd biasd and O/C reverse biased (similar to other diodes around it). Maybe i should remove it and test ? What do you think ?

The 780 seems to have less discrete diodes than the 500. Diodes i can see are listed below:

D58
D51
D50
D60
D59
D64
D63
D45
D55
D47
D46
D62
D61
D66
D65
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Re: 560 is possesed

Postby a1robotrepair » September 11th, 2016, 2:04 pm

That is what it should read using a diode checker.
D46 is good.
5V reg power, Q17 source to R138 to D47 to U3. U3 is an inverting switching regulator. It has current limit capabilities. 5V is fed thru out the board.
At this url http://www.onsemi.com/pub_link/Collateral/MC34063A-D.PDF you can scroll down to the diagram showing the 5V step down regulation. The first thing to check is the Schottky diode from pin 2 of U3. After that it could be any of a number of things drawing down the 5V, IF IT IS THE 5V THAT IS THE PROBLEM. An O-scope would be best to test, a DMM doesn't have enough impedance to see the 5V getting drawn low, shutting the system down, then resetting. Using a Simpson analog meter one should notice a needle deflection.
The area around the battery contacts is one of the critical areas to check and clean due to battery off gasses.
Schematic of 5V regulator circuit: http://www.robotreviews.com/chat/download/file.php?id=6127&mode=view
Last edited by a1robotrepair on September 24th, 2016, 7:02 am, edited 1 time in total.
Roses are red Violets are blue Poems are hard Flowers and Chocolate
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Re: 560 is possesed

Postby Kelad » September 12th, 2016, 6:26 pm

Cheers a1robotrepair, I'll do some more digging. Before i re-read your post, i cleaned PCB and reassembled. Same issue. I did notice that the battery is getting very very warm ! I have another 780 PCB which has blown IC's due to water damaged (got it for $2), so i will do some offline measurement comparisons.
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