Just FYI, Nec Display FC20X1SA-AB is used in my own Consonance pre.
I've read somewhere that there were 2 different heights used for the window framing the display, but I couldn't say if it's the same display with a different faceplate (or not).
I attach the datasheet just in case. I had to change mine once, bought a new one which is still working. I kept the broken one and I'll try to repair it someday, if possible, because when I see the prices asked for this display, I'm dazed. Don't know if JRDG still sell them, but at $350 it's cheap compared with the asked prices you can see online...
Remember, this preamp doesn't work with a broken display.
!!
I've read somewhere that there were 2 different heights used for the window framing the display, but I couldn't say if it's the same display with a different faceplate (or not).
I attach the datasheet just in case. I had to change mine once, bought a new one which is still working. I kept the broken one and I'll try to repair it someday, if possible, because when I see the prices asked for this display, I'm dazed. Don't know if JRDG still sell them, but at $350 it's cheap compared with the asked prices you can see online...
Remember, this preamp doesn't work with a broken display.
!!
OK, so I have a Jeff Rowland Consonance sitting on my bench right now that won't light up. It too has a FC20X1SA-AB display. Once I power it up, I get no clicking from the relays when press any buttons on the front panel. Taking a voltage reading in a few places including power to the display shows good. So what you are saying that when the display is defective, nothing at all works?
Also, I have another older but fully working JRDG Consonance that I was going to borrow its front panel for a test, but it uses the FC20X1NA-AB display which appear not to be pin compatible with the FC20X1SA-AB display.
Also, I have another older but fully working JRDG Consonance that I was going to borrow its front panel for a test, but it uses the FC20X1NA-AB display which appear not to be pin compatible with the FC20X1SA-AB display.
Hi Forrestc, sorry to read that.
From what I've seen on mine, when it got wrong, the day the display failed, the pre stopped working. That's the reason why I wrote that when the display is defective, the pre is out of service. At the time, I wasn't equipped to measure anything and didn't fix that kind of things at all. So I bought a new display (which was rather costly but available), and when I plugged it back, all was working again.
A few years later, after understanding more of what can go faulty in a device, I think that it can be repaired. I kept the faulty one (I keep most of the faulty PCBs I get, even my wife
), and while I didn't make any attempt to fix it, I'm rather confident that I can do it if necessary.
Here are 2 pictures of my "wrong" one (a FC20X1SA-AB, same as yours) :
Except the display itself (VFD module) and probably the chip, I guess all components can be replaced. I didn't try it yet. Normally, if I read the data sheet correctly, the display should work with a 5V input (can't say where right now). Then, there's a fuse (soldered) that I haven't tested yet, but I would check it, as well as the capacitors. I think their function is to keep the display lit if turned off too quickly after lighting (so it won't be stressed by a short impulse). Not sure about that. There is that page (https://www.maltepoeggel.de/?site=vfd), written in German (but google translatable), which can be informative about the display and how it works). Maybe you'll get some usable knowledge from it.
I'm sorry not being able to say more right now. If you need I can get my old one out and have some tests on it. For the one that works, it's less easy because the pre is in its place and It will take some time to get it out, open it and make some measurements... But if it can help you and that you ask me precise voltage readings or so, I can try to do it.
Last point, I usually keep the display off. My pre is on 24/7, and after I replaced it, I preferred to keep it unlit to "save" it (don't know if it is useful though).
I do hope you can repair yours, or at least understand what goes wrong. It worths it, and the replacement displays are horribly expensive when you can find some. I stay at your disposal.
Best, Jerome.
From what I've seen on mine, when it got wrong, the day the display failed, the pre stopped working. That's the reason why I wrote that when the display is defective, the pre is out of service. At the time, I wasn't equipped to measure anything and didn't fix that kind of things at all. So I bought a new display (which was rather costly but available), and when I plugged it back, all was working again.
A few years later, after understanding more of what can go faulty in a device, I think that it can be repaired. I kept the faulty one (I keep most of the faulty PCBs I get, even my wife
), and while I didn't make any attempt to fix it, I'm rather confident that I can do it if necessary.Here are 2 pictures of my "wrong" one (a FC20X1SA-AB, same as yours) :
Except the display itself (VFD module) and probably the chip, I guess all components can be replaced. I didn't try it yet. Normally, if I read the data sheet correctly, the display should work with a 5V input (can't say where right now). Then, there's a fuse (soldered) that I haven't tested yet, but I would check it, as well as the capacitors. I think their function is to keep the display lit if turned off too quickly after lighting (so it won't be stressed by a short impulse). Not sure about that. There is that page (https://www.maltepoeggel.de/?site=vfd), written in German (but google translatable), which can be informative about the display and how it works). Maybe you'll get some usable knowledge from it.
I'm sorry not being able to say more right now. If you need I can get my old one out and have some tests on it. For the one that works, it's less easy because the pre is in its place and It will take some time to get it out, open it and make some measurements... But if it can help you and that you ask me precise voltage readings or so, I can try to do it.
Last point, I usually keep the display off. My pre is on 24/7, and after I replaced it, I preferred to keep it unlit to "save" it (don't know if it is useful though).
I do hope you can repair yours, or at least understand what goes wrong. It worths it, and the replacement displays are horribly expensive when you can find some. I stay at your disposal.
Best, Jerome.
Presently working on my old faulty display, your post took me to it... ! As I said previously, beside the fuse which is faulty, for sure, I suspect the 2 capacitors nearby the input 5V entry to be out of specs. A quick measurement (not easy to make between the glass and the PCB, and as they are in place not precise, even between the plus and minus of the 2 caps which are probably in series) showed a very very low and improbable value (like nF). Not many options, except unsolder them from the PCB and see in real life. I took some air and...
...First I separated the VFD and the PCB. Not so difficult but time consuming to keep the little pins from the VFD glass soldered on the PCB in good shape. And cut the adhesive foam in the middle to avoid destroying some tracks on the PCB. Picture after that.
Then it's easy to see that there has been some trouble in the area nearby the caps. I took me some time to unsolder those 2 little babies (22µF/35V polar Nichicon caps), but nice to be able to measure them properly. Well, at least, one of them, because one pin of the second broke (was broken?) when I took it out. Capacity of the only one I could measure is around 40nF on my Fluke... So at least, we have some culprits: those 2 caps (C10 and C11 on the PCB)
After a good cleaning it's better.
I don't know if I can test the PCB with 2 temporary caps and fuse easily because I would need to re-solder the VFD 24 pins and I don't want to have to make that several times, if the problem is not ONLY about these faulty caps. Moreover, I miss some adhesive foam to make it clean as it was and have to order some. If you experts have any ideas, I'm ready to experiment them!
Work in progress...
...First I separated the VFD and the PCB. Not so difficult but time consuming to keep the little pins from the VFD glass soldered on the PCB in good shape. And cut the adhesive foam in the middle to avoid destroying some tracks on the PCB. Picture after that.
Then it's easy to see that there has been some trouble in the area nearby the caps. I took me some time to unsolder those 2 little babies (22µF/35V polar Nichicon caps), but nice to be able to measure them properly. Well, at least, one of them, because one pin of the second broke (was broken?) when I took it out. Capacity of the only one I could measure is around 40nF on my Fluke... So at least, we have some culprits: those 2 caps (C10 and C11 on the PCB)
After a good cleaning it's better.
I don't know if I can test the PCB with 2 temporary caps and fuse easily because I would need to re-solder the VFD 24 pins and I don't want to have to make that several times, if the problem is not ONLY about these faulty caps. Moreover, I miss some adhesive foam to make it clean as it was and have to order some. If you experts have any ideas, I'm ready to experiment them!
Work in progress...
Thank you Jerome for the in-depth and informative insight into something I know very little about. Now I have some direction on where to start looking.
I do have one other question though. The jumper on the PCB in the Consonance that is labeled DISPLAY Test/Run, I am guessing that when in the test position, the display should scroll through it's complete character set. Is that what you find? In my case when I move the jumper to the test position and restart the preamp, the display is still dark.
Also, there is a amber LED on the preamp's PCB that remains on but faintly lit while it is powered up, but at one time I did see it flashing a rate of about one flash cycle per second. I'm not sure what this LED indicates.
I do have one other question though. The jumper on the PCB in the Consonance that is labeled DISPLAY Test/Run, I am guessing that when in the test position, the display should scroll through it's complete character set. Is that what you find? In my case when I move the jumper to the test position and restart the preamp, the display is still dark.
Also, there is a amber LED on the preamp's PCB that remains on but faintly lit while it is powered up, but at one time I did see it flashing a rate of about one flash cycle per second. I'm not sure what this LED indicates.
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You're welcome, Forrestc.
I've been cleaning the PCB thoroughly and I can see the circuit more accurately.
What I thought to be a fuse, next to PCB label, seems more likely to be a Quartz? It's in parallel with 2 caps (C1 and C2) which feed different pins of the VFD controller. Written on it: 3.68 CmY. Unfortunately I couldn't find any information about such a component... If someone has an idea? Same for this controller (NEC FIPC8367), Google doesn't seem to know that component...
This is far beyond my skills anyway.
The only way to know what it is (and maybe find the actual value of it) is to open my Consonance and have a look on the functional display PCB.
Then about the points you mention in your last post, I can't answer before opening the machine. Unfortunately I don't have inside pictures at hand so I don't remember that particular display test/run jumper. I'll have a look, same for the amber led that I do remember but not how it flashes. I'll have a closer look soon.
Best,
I've been cleaning the PCB thoroughly and I can see the circuit more accurately.
What I thought to be a fuse, next to PCB label, seems more likely to be a Quartz? It's in parallel with 2 caps (C1 and C2) which feed different pins of the VFD controller. Written on it: 3.68 CmY. Unfortunately I couldn't find any information about such a component... If someone has an idea? Same for this controller (NEC FIPC8367), Google doesn't seem to know that component...
This is far beyond my skills anyway.
The only way to know what it is (and maybe find the actual value of it) is to open my Consonance and have a look on the functional display PCB.
Then about the points you mention in your last post, I can't answer before opening the machine. Unfortunately I don't have inside pictures at hand so I don't remember that particular display test/run jumper. I'll have a look, same for the amber led that I do remember but not how it flashes. I'll have a closer look soon.
Best,
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I'm now pretty sure that that component I thought was a fuse is a ceramic resonator, 3.68 MHz, 2 pins. On that picture of a new FC20X1SA-AB on the Bay right now (with a ridiculous $2500 tag price):
it is absolutely clear that there are 2 locations for such a resonator (labeled QZ1), one for CMS resonator (my version) or one for a through hole 2-pins component (this one).
So I re-soldered the one I had unsoldered previously but with the labeling on the top (so that everyone can read what it is).
I ordered double-sided adhesive foam tape (so I can bond the PCB and the display) and a couple of 105°C 22µF/35V caps of the perfect size. When received, I'll finish the job.
it is absolutely clear that there are 2 locations for such a resonator (labeled QZ1), one for CMS resonator (my version) or one for a through hole 2-pins component (this one).
So I re-soldered the one I had unsoldered previously
but with the labeling on the top (so that everyone can read what it is).I ordered double-sided adhesive foam tape (so I can bond the PCB and the display) and a couple of 105°C 22µF/35V caps of the perfect size. When received, I'll finish the job.
I can't wait to see the results; fingers crossed for a successful repair.
As for my Consonance VFD issue, I decide to disconnect the two-wire power connector to the VFD. Once I powered it back up. the small LED on the Consonance's PCB started flashing and relays started working again. For this reason, feel fairly confident that there is an issue with the VFD. Also, when the two-wire power connector to the VFD is disconnected, I measure about 9.8V open circuit across the connector; however, when it is reconnected, I measure only about 2.5V across the connector and everything stops working. Something on the VFD board must be pulling down the voltage/drawing too much current. Moreover, you can actually see some heat discoloration on the underside of the Consonance's PCB around the power supply's regulator section.
As for my Consonance VFD issue, I decide to disconnect the two-wire power connector to the VFD. Once I powered it back up. the small LED on the Consonance's PCB started flashing and relays started working again. For this reason, feel fairly confident that there is an issue with the VFD. Also, when the two-wire power connector to the VFD is disconnected, I measure about 9.8V open circuit across the connector; however, when it is reconnected, I measure only about 2.5V across the connector and everything stops working. Something on the VFD board must be pulling down the voltage/drawing too much current. Moreover, you can actually see some heat discoloration on the underside of the Consonance's PCB around the power supply's regulator section.
That's insane! $2500 would be the value of about THREE entire working JRDG Consonance line-level preamps in the current market.
Thanks Forrestc. What you write about too much current drawing makes me think about something. When I connected my faulty VFD to a 5V/0.5A lab power supply (constant voltage), I read 1.5V on the PSU, instead of 5V. So something was draining current and it cannot work with so little voltage. On the board, for sure, the 2 small caps (22µF/35V) are washed up. Is it enough to make this happen? I'm not a engineer, so I can't really say, I'm just able to note it!
I should have both caps and adhesive foam soon, then I'll be welding and reassemble glass and PCB. After that I'll try a transplantation and hope to give (good) news next weekend.
Insane, that's the word. Normal price for actually sold Nec or equivalent VFDs on the Bay is more often around $350-500. I doubt the one priced $3000 - see here - even more than $2500 I've seen before... will ever sell that price. But that kind of display is also found in many medical and industrial devices of that time (1985-95), and some of them are probably vastly more expensive than our JRDG machines - and maybe worth the cost of replacing. ?? Well, if the repair is that simple, that's a business to create!
Good evening
I should have both caps and adhesive foam soon, then I'll be welding and reassemble glass and PCB. After that I'll try a transplantation and hope to give (good) news next weekend.
Insane, that's the word. Normal price for actually sold Nec or equivalent VFDs on the Bay is more often around $350-500. I doubt the one priced $3000 - see here - even more than $2500 I've seen before... will ever sell that price. But that kind of display is also found in many medical and industrial devices of that time (1985-95), and some of them are probably vastly more expensive than our JRDG machines - and maybe worth the cost of replacing. ?? Well, if the repair is that simple, that's a business to create!
Good evening