preenfm Forum
PreenFM => preenfm2 and preenfm3 => Topic started by: Kyg on August 06, 2021, 08:09:36 PM
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Hi,
I built a PreenFM3 a few weeks ago and have been very happy and impressed with it!
Wonderful synth engine, interface, and a fantastic variety of filters! Thanks for a great synth!
The one thing that is bothering is that the display occasionally goes blank. I know that this is supposedly due to noisy power and changing to a different USB power supply did improve the situation. I also know that a function was already implemented in the firmware that automatically resets the display when it goes blank. This works sometimes but often I still have to reset the display manually by pressing MENU and -.
My observation is that the display never or only very rarely goes blank when the PreenFM3 doesn’t receive any MIDI information. I can have it on that way for many hours and the display stays perfectly fine. But when the unit plays the display does go blank often. The frequency of blank screens seems to depend on the load on the synth engine (how many notes, voices, active sound channels etc.)
I’m no techie and I could be completely wrong, but to me the dependence on synth engine load might indicate that the cause isn’t noisy power. BTW, none of my other synths and effects etc. have ever shown any signs of power issues.
I doubt that my solder connections to the display are weak and I’ve tried numerous different USB power supplies and power outlets.
I'd be glad for advice how to solve this!
Thanks,
Phil
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I thought this problem was gone :-\
You said it seems to be related to midi activity.
Both DIN5 and USB ?
Don't you think it can be realated to Display activity that follow midi note ?
Have you tried to use the sequencer with all level metter on ?
Let it play (without midi data) with the display showing all level metters and see if it's stable.
When the TFT does not change, no data is sent to it. So it's stable.
The CPU only send data when the display has something new to show.
From all the tests i've made (and i've made a lot), the problem was some random corrupted data (due to external noise), that puts the TFT in a bad state.
The TFT displays is today very stable on the preenfm3s i have. (I had to tweak many parameters in the firmware).
Is your TFT soldered ? or do you use a connectors between the main board and the TFT ?
Let me know if you found something,
I can make a firmware with slower Data transmission to the TFT, to see if that makes change.
Xavier
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Hi Xavier,
Thanks for your help!
I ran the Sequencer on 4 tracks today with level meters on and the display went blank frequently (requiring MENU and -, auto detection didn’t work)
As soon as I stopped the Sequencer the display became perfectly stable again.
Btw, the firmware file I installed was the current v0.107. However, the Preenfm3 displays v0.106.
Regarding the TFT pins, I soldered the 4 top pins but used a connector on the row of bottom pins.
Phil
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Hi Xavier,
if you have any more insights about possible solutions for the blank TFT or anything else I could try to diagnose what’s causing it, please let me know!
Thanks,
Phil
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Hi Kyg,
The most likely reason is some noise on the CPU to TFT lines.
If your soldering is clean on the TFT connector, that can be the connector itself. Try remove the TFT and to push it back.
You can also try to change the connector (i know it's a real pain), or to solder directly the TFT without connector.
I finally found time to compile a firmware with a slower (4 times slower) communication between the CPU and the TFT.
I attached 0.107s (s for slow ;) )
I hope that will prevent the TFT from receiving corrupted data.
So before doing anything you can try this firmware and see if that makes a difference.
Xavier
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Thanks so much for your help at solving this, Xavier!
I will check with the new firmware and let you know!
Phil
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Hi Xavier,
I tested the modified 107s firmware. My impression is that the slower update rate of the TFT hasn’t improved the issue and that the display goes blank just as often as it did with the regular firmware.
I guess I will have to try to replace the display connector and solder it directly.
But, in any case, the issue doesn’t really affect the usability of this great little synth!
Thanks,
Phil
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Hi Xavier,
I have one more question about the display going blank:
Whenever this happens, pushing MENU and + always gets the display back to normal. The CONFIG setting to auto detect sometimes works, but eventually there is always a moment when it doesn’t work. That’s when I need to reset the display manually.
Wouldn’t it be possible to fix the auto detection to always work?
Or could the reset simply be automatically done at regular intervals?
Thanks,
Phil
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The autodetect is the preenfm3 that regularly asks the TFT if it's still alive.
If the TFT does not reply, then a TFT reset is triggered.
I think there are some cases where the TFT is blank but it still replies that it's alive.
Sorry, there's not much i can do.
But this blank screen does not occure anymore on any on my preenfms.
It was a real problem on early firmware.
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If you have time, could git a try to firmware v1.05.
https://github.com/Ixox/preenfm3/releases/tag/v0.105
This one does not have "TFT backlight" feature that send Pusle Width Modulation to the TFT to adjust the led intensity.
Would be interesting to see if it's more stable without it.
Thanks
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Great! I will try that firmware and report back.
Thanks,
Phil
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Hi Xavier,
sorry it took me a while to report back!
I did some extensive tests with Firmware 105, but the display also blanks out with this firmware.
This time, I used a stop watch to check how frequently the display goes blank. With four MIDI tracks playing four voices in the PreenFM3 the display went blank far more frequently than with just one MIDI track.
I remain a little skeptical about the TFT connectors causing this. But I will, at some point, resolder the TFT in the hope that it solves the problem.
I could be wrong, but my impression is that the display only goes blank with display activity from external MIDI data but not from display activity when using the PreenFM3 knobs and buttons. If that is so, would it be reasonable to think that a PERF screen without the oscilloscope would not go blank?
Thanks,
Phil
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I did some extensive tests with Firmware 105, but the display also blanks out with this firmware.
Too bad.
But it's good to know.
I could be wrong, but my impression is that the display only goes blank with display activity from external MIDI data but not from display activity when using the PreenFM3 knobs and buttons. If that is so, would it be reasonable to think that a PERF screen without the oscilloscope would not go blank?
Didn't you say that the sequencer playing alone without any external midi also crashed the screen ?
"External midi" ? Both USB and Din5 midi jack ?
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Yes, that’s true. I forgot that I tested it before with the internal sequencer and also got a blank display.
I just don’t remember ever editing any parameter and the display going blank at the same time. I guess that’s why I thought that changes on the display from editing may not result in a blank display.
I haven't used the USB Jack for MIDI in my setup.
I guess I’m still hopeful that there may be a solution to the blank display other than me having to resolder the TFT.
Thanks for all the attention you have already given this!
Phil
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Hi, Kyg!
Any news about your problem?
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Hi,
after a long time away from my music equipment, I’m just coming back now and am currently using the PreenFM3 remote controlled via the editor software without ever looking at the display of the synth. So I haven’t attempted to fix the display yet.
I just read in another thread on this forum that someone might have successfully fixed their display by installing a different display. The person provided a purchase link for that on Amazon. My impression is that I should just buy that display instead of trying to re-solder the display that came with the PreenFM3 kit.
But I probably won’t deal with that anytime soon and am quite happy using the PreenFM3 through the editor only.
And just to say it again: I love the synth engine and the sounds I’m getting from the PreenFM3!
Phil
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Oops, seems like the person who asked me for an update might have been the one who tried a different display!
So, I guess that didn’t work out after all.
Phil
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cokosha, do you have the same problem ?
To both of you, I have a few spare TFTs in stock.
So i can try one and ship it to you.
I won't be at home before end of August, please contact me then.
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Hi Xavier,
if you try your spare TFTs and think they might be a fix to the problem, I’d be happy to buy one!
I’ll contact you at the beginning of September.
Thanks!
Phil
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Does it turn all white? That happened to me frequently and I bought another screen and the problem went away. I happened to use one of the touch versions of the screen. I think some screens have more problem with this than others.
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Thanks for your reply, JDL…
And thanks for confirming that swapping out the display is a possible fix for the screen going all white.
I’ll go that route after I check back with Xavier at the end of August.
Thanks,
Phil
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Could people post links to TFT screens that they have had problems with and that have worked without any issues? That could be a handy old list?
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Sorry for the double post.
I can't seem to find any ILI9341 TFT that is not touchscreen.
Ardi @ VanDaal suggested using a non-touchscreen TFT.
So- could anyone please provide a link to a non-touchscreen ILI9341 TFT?
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Hi,
this one may do the job :
https://www.amazon.co.uk/dp/B07KPF15B1/ref=pe_3044141_185740131_TE_item
That's the one i'm using on my pfm3.
Works fine, but i had to fix it first by soldering the sd card pins myself...
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Thank you- unfortunately that link says the product is now unavailable.
Further suggestions welcome!
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ah, i think availability is location dependant, the tft is available from that link on my side...
What country are you from ?
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Post removed to avoid confusion for other users.
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those seems to have touchscreen...
on aliexpress, there is some 2.8" ILI9341 tft, without touch function :
https://fr.aliexpress.com/item/1005003950848515.html?spm=a2g0o.search0304.0.0.48896b3dm5muod&algo_pvid=b1e47fc9-b227-4291-813b-5e79d1faa7d9&algo_exp_id=b1e47fc9-b227-4291-813b-5e79d1faa7d9-27&pdp_ext_f=%7B%22sku_id%22%3A%2212000027556977906%22%7D&pdp_npi=2%40dis%21EUR%21%2110.33%21%21%21%21%21%402101e9cf16607160703906081ed581%2112000027556977906%21sea
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those seems to have touchscreen...
Thanks, I guess it makes sense that Press Panel means the same thing as Touch Display.
I have removed the links in my previous post to avoid any potential confusion.
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The touch layer adds around 1mm of thickness and it may not fit the VanDall case + plexi protection.
You may want to verify.
If you don't see the U2 chip soldered on the back of the PCB on the pictures, it does not have the touch layer.
You can read this page for more info about the TFT :
https://github.com/Ixox/preenfm3/wiki/TFT
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Oh, in that case the one in Toltekradiation's link above is still touchscreen after all, as it has the U2 chip according to the pictures in the product description.
Still looking then for a non-touchscreen TFT!
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I think Toltekradiation's link above is OK if you select "No Touchscreen".
They simply use the same pictures for both options.
I just saw your PM, i'll reply in a minute.
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Hi Xavier,
you mentioned a couples of posts back on this thread that you have some spare TFTs that you could test and possibly ship one to me. If you still have those, I would be happy to buy one from you.
Thanks,
Phil
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Hi Xavier,
you mentioned a couples of posts back on this thread that you have some spare TFTs that you could test and possibly ship one to me. If you still have those, I would be happy to buy one from you.
Thanks,
Phil
Hi Phil,
How is your preenfm3 ? Metal box from van daal ? inserted in headers or soldered directly ? What PCB version ?
I try to gather infos to see if preenfm3 with display problems have some similar features.
PM me your shipping adress and i'll let you know the details.
Xavier
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Hi Xavier,
My PreenFM3:
Metal case from Van Daal
Headers for the TFT
PCB 1.6
I'll PM you my address.
Thanks a lot!
Phil
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Hi Xavier,
I wanted to thank you for sending me the replacement TFT display!
I haven’t had the time yet to install it, as I just moved to a new job and home and have been busy with that. But I very much appreciate your attention and help with the TFT display issue!
Thanks a lot!
Phil
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Yes I echo Phil's comments- thanks for your support Xavier.
Others who are replacing TFT screens in Van Daal's FM3 builds may want to note that, because of the case design, Van Daal used long leg headers to connect the TFT to the PCB, so the display directly touched the clear plastic cover in the case and held it in place. The replacement TFT screen will probably have short leg headers. Therefore when you put the new TFT in, the TFT display height will not be level with the screen opening in the case, and therefore won't hold the clear plastic screen cover in place in the case.
If you really wanted to you could do some soldering work to put long leg headers on the new TFT screen. I haven't done that, I've just used duct tape around the edge of the clear plastic screen cover inside the case to attach it to the case. The display does sit a little below the plastic screen, but I haven't found that to be a problem.
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Unfortunately I still have the same problem... firmware 110, built up by Van Daal.
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Hi,
Reasonable prices for the TFT are back on amazon : around 18€.
Search for "2.8" ILI9341" and check the back of the PCB.
I bought several times the "Hailege" brand. It works fine. It has an additional touch layer, so double it will fit in your preenfm3.
More information here :
https://github.com/Ixox/preenfm3/wiki/TFT