Help! - MTN-20DD driver with guppydrv always starting in next mode

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drillbitz11
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Help! - MTN-20DD driver with guppydrv always starting in next mode

So, I just put together a MTN-20DD for an eagletac D25C and everything seems to be fine except the mode memory. It is always turning on in the next level from where I turned it off. The mode group I choose (memory or no memory) doesn’t seem to make a difference. Neither does the length of time I leave the light on or off. Its loaded with guppydrv rev1. firmware. Does anyone have an idea what could be causing this?

Edited by: drillbitz11 on 09/04/2015 - 23:13
shanefletch
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Subscribing to this thread – I have the same issue, never figured out the solution.

Tom E
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I can't help too much - don't have that particular one and there's no pics here or on the MtnE site. It should have a cap on the board for OFF time memory, and seems like that functionality is not working. If the firmware thinks the cap is always almost fully charged, it will always do the next mode. So, this is a possible cause of this behavior (cap is not functioning correctly due to possible bad solder joint or bad cap).

The OTC (OFF time cap) should be the smaller of the 2 caps - one end of the cap is directly wired to a pin of the MCU. It should be a 1 uF (http://www.mtnelectronics.com/index.php?route=product/product&path=25_104&product_id=310).

I could be wrong here - again, not knowing or familiar with this specific board or this specific firmware.

Kloepper Knife Works
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Can you take a picture of the board? I’m also suspecting a problem with the off time cap.

drillbitz11
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I tried reversing otc and c1 to and ended up with direct drive (no modes) so I decided to replace both capacitors as well as the MCU and ended up at square 1; always restarting on the next level from where I shut it off. So I decided to build another driver using the same parts but this time a 17mm. put it in a p60 dropin and it works perfectly. I couldnt build another for the same d25c host because I dont have another 20mm board. I purchased the capacitors at Digikey 10uf 16v 10% x6s 0805 and 1uf 16v 10% x7r 0805. Could it have something to do with the FET? I mean being faulty or damaged. I know its not the model since I purchased it from Richard at ME.

drillbitz11
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It tried posting a pic but I’m not sure what Im doing wrong…heres a link to the board (17mm but the 20mm is the same)

17mm Single-Sided FET Driver PCB – V1.1 – MTN-17DD

What happens if I do away with the OTC completely?

pyro1son
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If the parts are all working perfectly on the 17mm board then I would suspect there is an issue with the 20mm version, bad trace ect… try getting another board.

Pastebin                                      &nbs

Tom E
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drillbitz11 wrote:
It tried posting a pic but I'm not sure what Im doing wrong...heres a link to the board (17mm but the 20mm is the same) "17mm Single-Sided FET Driver PCB - V1.1 - MTN-17DD":http://www.mtnelectronics.com/index.php?route=product/product&path=25_10... What happens if I do away with the OTC completely?

For pics you need to post the pics on a file/picture sharing hosting site, like PhotoBucket or others. The when you edit a post, use the tree symbol to insert an image, and in the image URL field, insert the link - preview than should work than in the Insert/Edit Image popup.

Not sure off-hand if you simply remove the OTC - if the firmware is trying to use it, probably next mode memory, or doesn't change modes at all. Form what you are describing, it is sounding more like some sort of trace problem in the board itself, but you should be able to find that from buzzing out the traces.

ohaya
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Why not contact RMM about this?

drillbitz11
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Thanks guys.I’ll check the traces…

pscal
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I had this problem once. One of my capacitors (unsure which one) was not charging and discharging properly. I bought replacements for both C1 and the offtime capacitor, installed them, and my problem was solved. Try re-flowing the capacitors, and if that doesn’t work, try replacing them.

hank
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Same problem with next mode memory on a 17mm 4×7135 driver.
I just asked about it in the Mtn. thread.

Capacitor replacement. Huh.
Argh, I’ve never managed to reflow a driver, guess I’ll have to this time.

RMM
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We check for memory function before we send these out.  Sometimes during installation the boards get flexed a lot and a solder joint can break, or sometimes the capacitor gets shorted out.  

Hank, your driver doesn't use an OTC at all, so this thread isn't where your problem lies. 

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