Messages

1

preenfm2 and preenfm3 / Re: Random patch resetting - was yellow oled issue

« on: June 29, 2019, 06:18:16 PM »

Xavier - Apologies for not replying sooner as this was a busy week. While I initially said I wouldn't be opening up the synth again until about this time, in fact I immediately turned around after my last reply and opened the synth back up! (Because who needs sleep when you could get a PreenFM up and running?)

The first thing I realized was that things were a lot more cramped with the insulated ground plate under the OLED than I initially thought. One consequence was that the wire coming from MCLK patching the defective trace was mashed such that it was possible intermittent shorts could occur with adjacent pins. And while I didn't see any evidence, I couldn't rule out random shorts occurring with solder joints piercing the insulation of the grounded shield. So I covered the circuit board under the shield with a layer of electrical tape, paying extra attention to really isolating the wire tacked to pin 6 of the 405.

I have been running the synth continuously since then, with and without sequencers running for many hours, and with as much hands-on as the past few days have afforded me. I think it's safe to declare this synth operational! So yes, it took you telling me to look at pin 6 to actually consider that might be the problem despite the big ugly wire hanging off of it. But now I've hopefully made the synth robust and if not, I know where to concentrate future improvements/modifications.

Once again,
Thank You!

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preenfm2 and preenfm3 / Re: Random patch resetting - was yellow oled issue

« on: June 25, 2019, 04:37:47 AM »

Hi Xavier,

I think I might know the issue. I haven't had time to disassemble the synth yet, but I went back to my original post about the bad trace on the r5c board I had to see which pins I had to jump together to complete the damaged path (https://ixox.fr/forum/index.php?topic=63547.msg65848#msg65848). Sure enough, it's pin 6 MCLK on the 405 over to a 74H166. The wire used to effect the repair runs directly under the insulated & grounded plate used for the yellow OLED fix. Maybe I'll go back and find the damaged trace and see if I can bridge it where it's damaged so I can then remove the wire under the OLED shield..? In the mean time, I'm open to any and all suggestions!

3

preenfm2 and preenfm3 / Re: Random patch resetting - was yellow oled issue

« on: June 22, 2019, 03:08:03 PM »

FYI - it's currently running OS 2.07. (I've recently moved and my shop and computer are still getting unpacked.) Also, the problem is much more apparent and occurs far faster when midi is being received.

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preenfm2 and preenfm3 / Random patch resetting - was yellow oled issue

« on: June 22, 2019, 03:05:22 PM »

Greetings! I have a metal cased, R5C PreenFM2 complete with the wonderful Newhouse yellow OLED. I've had the synth for years and it's never worked right. However, what playing I've done has convinced me that this is - or could be - my all time favorite FM synth even with all the newer entries now on market. Alas, I get to working on it, resolve a problem or two, then life causes the work to be sidelined, repeat cycle, and here we are in 2019 and I still want a working Preen! When I first received and assembled the kit, there was a faulty trace that I fixed that was a manufacturing error on some of the r5c's. Shortly there after, I started getting display errors once the synth had been running for a while. Turns out the OLED was running really hot with way too much current draw. While the evidence indicated the OLED was defective from the gitgo, I purchased a replacement. Then the display errors returned, but this time the OLED was running cool and within spec. Flash forward to the present. I have performed the 22ohm resistor/shielding plate modification on the synth and now my display is rock solid and crystal clear...

HOWEVER, now when I run the synth, it will randomly unload/reset/reinitialize any loaded patches I have. For example, if I load a combo, a few seconds later it's changed to Preset 004, 005, and/or 006. Even that isn't stable as sometimes I'll watch a voice occasionally toggle from one value to the next (e.g. Back and forth between Preset 005 and 006). This seems to occur with the same random nature that the OLED display error occurred and has got me wondering if this has been going on the whole time I've had the new OLED, but went undetected because I was fixated on the display errors at the time.

Could this be noise on the USB_DP & USB_DN lines? Anybody else experience this? I'm VERY interested in 'eurofying' my Preen, but I need to get this synth up and running and rock solid first. It's been too long! 

TIA

5

preenfm2 and preenfm3 / Re: No buttons or encoders - solved

« on: February 09, 2016, 02:56:27 PM »

No need to be sorry! First of all, as you probably figured out, I meant to say I thought the break was in the trace between pins 15 and 16 of the 74165.  Im on the other side of the pond and it was way past my bedtime!

I'm not the greatest craftsman when it comes to yielding a solider iron, but I've been involved with electronics most of my life thus have some experience.  The connections were all good with no bridges, cold joints, over or under soldiering.  While I reflowed the contacts in question, none of the pads were overly cooked and damaged.  I felt I checked my work and the schematic about 1000 times before I applied the jumper wire fix.  Again, I could occasionally get the synth to boot up in its normal mode as opposed to the boot loader screen.  At first I thought this was because I hadn't seated the chips properly, but it would only boot up right after my pressing or somehow slightly flexing the board and won't boot right on subsequent tries.  That's when I really started suspecting a crack in a trace.  Then, when I found that just the application of my finger around the 74165s and resistor network while the synth was unplugged was enough  'stimulus' (charge or discharge of what ever small voltages were there at the time) to consistently allow the synth to boot in the right menu (but still w/o button or encoder functionality), I became convinced there was an open in the curcuit somewhere and I began the steps to find and fix it.

BTW, the forum topic where mmarsh had no button functionality really helped me narrow the problem down.  Not only because of how it was related to my problem, but because I figured if someone like him could resolve his problems to go on and create fantastic sounding music and demos with the Preen, than maybe there was hope for some poor soul like me!

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preenfm2 and preenfm3 / Re: No buttons or encoders - solved

« on: February 09, 2016, 09:42:29 AM »

I picked up the kit from Van Daal.  I'm not 100% certain where the trace is broken, but I suspect it's where it passes between the pins (9&10 I think) of the 74165.

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preenfm2 and preenfm3 / No buttons or encoders - solved

« on: February 09, 2016, 08:32:32 AM »

Hello Xavier,

I just built a PreenFM2 kit and had an issue I haven't seen on this forum before that I thought I would share.  When I first turned my preen on, I got the boot loader screen and none of the buttons or encoders would work.  After poking and prodding, I could get the synth to boot normally, but still with no encoders or buttons. A reboot would simply put me back to the boot loader screen.  After much more poking and prodding, I came to find that if I so much as lightly touched the leads around the resistor networks, I could boot into the normal screen.  Every subsequent reboot would take me to the boot loader screen until I lightly touched the leads anywhere around the control scanning circuits a which point I could reboot to the normal screen again.  I suspected a poor solder joint but could never locate one.  Eventually I got the schematic and systematically checked connections until I realized that pin 1 from both 74165s were not reaching pin 6 of the 405.  This turned out to be a defective trace on the pcb as opposed to anything I did or didn't do while assembling the circuit. A small wire soldered between pin 6 on the 405 and pin 1 on one of the 74165s was all it took to have my preen up and running! Now it's hooked up to an Undead Instruments Timefrog purring in the background while I write this email. Time to go play with it some more!