Roland DEP5 - Fluoresent Display without function
- Thread starter rock soderstrom
- Start date
Help Support GroupDIY Audio Forum:
Most likely my display is done as it’s got a crack. I still don’t understand why I’m getting nearly 40v but it might be that display doesn’t take all the load it meant to.
What is the problem you’re experiencing?
When it happened and are you original owner?
Audioman
Well-known member
Hi Adrian55, my dep5 was purchased used about 20 years ago and the problem I'm experiencing originally started with the sudden failure of the display to turn on, I therefore decided to recap all the electrolytic capacitors on the power rails, having solved the problem for it went back a little, but after a while it came back. I changed the two chips IC 14 and IC15 here because one of the two was heating up to 85 degrees centigrade, but the problem now is that some segments of the display do not work correctly
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It’s important to check unit for voltages as there might be other consecutive things happening which through examining would expose.
There is a post from earlier on where one forum buddy says that he’s got two units and one works with display and it doesn’t on other unit so there’s definitely something more sophisticated happening that is hard to spot without thermal cam.
There is a post from earlier on where one forum buddy says that he’s got two units and one works with display and it doesn’t on other unit so there’s definitely something more sophisticated happening that is hard to spot without thermal cam.
Audioman
Well-known member
@Adrian55 I also replaced the Q12 BJT because it also reached a temperature of almost 90°, but this didn't help because the new one (an equivalent) heated up the same, and I also checked the original BJT with the transistor tester and in fact it wasn't damaged.
I am attaching the YouTube link of a video I made on my display while I was operating the rotary controls on the front panel of the multi effect
I am attaching the YouTube link of a video I made on my display while I was operating the rotary controls on the front panel of the multi effect
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I’ve posted on this already but this is what is happening with mine too and it’s not the display, well for me, as a working swap does same. I’m going to clear my current repair load then get back into this problem too
Yup I think too that display can be filled out as there is same two segments that don’t lit up. So maybe there is something that pulls them to ground all the time? Resistor array bad? Maybe controlling IC?
Need to to look up schematic.
I did check traces from cpu controller as I did wonder if it was that. I don’t have sufficient logic kit, or probably knowledge, to take further if it is that surface mount ic. As to res networks…I have a feeling I checked or replaced those. What I didn’t do was replace some of the trannies mentioned here as couldnt source them. The digital ones I mean. I still wonder if it’s something fairly simple tho as the screen isn’t dead it’s just a few segments that aren’t being told to turn on. My screen swap proved that assumption and ruled out a fip display issue.
Unfortunately I’m no guru and not sure what the purpose of those two dtc ones is for
