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#1721382 - 03/16/21 12:43 PM 1680 screen issues
DCore Offline
Planeteer


Registered: 03/02/20
Posts: 65
Loc: Washington State
Hello,
I am looking at a VS-1680 with a screen issue and I would like to know if you have ever seen a 1680 screen look like this one. I am familiar with screen failures where the backlight dies and the letters are only legible if you hold a flashlight to the screen but this rainbow look is a new one for me. Might this possibly be a failure of a component on the the screen board instead of a more typical backlight failure? Let me know your thoughts.

https://imgur.com/a/OzBVjOO

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#1721387 - 03/16/21 01:21 PM Re: 1680 screen issues [Re: DCore]
uptildawn Offline
Planeteer


Registered: 12/15/01
Posts: 8899
Loc: on land
It's just a guess on my part, but it looks to me like a display issue. In my experience, it reminds me of how my old crt tv screen got destroyed when I accidently got a big guitar amp transformer too close to it one time. Like I said - it's a guess.
_________________________
uptildawn

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#1721632 - 03/17/21 08:46 PM Re: 1680 screen issues [Re: uptildawn]
RD Offline
Planeteer


Registered: 07/29/02
Posts: 1376
Loc: Michigan, someplace near a swa...
Yeah mine did...funny, I said in prior thred that I had never had any issues with my 1680 except hard drives... But then I remembered a couple years ago I took it into our Roland tech because the screen failed.. it wasn't hugely expensive..

Good luck...


Edited by RD (03/17/21 08:46 PM)
_________________________
Using VS 1680 24 years now and counting!

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#1721687 - 03/18/21 03:50 AM Re: 1680 screen issues [Re: DCore]
gyorpb Offline
Planeteer


Registered: 05/11/19
Posts: 206
 Originally Posted By: DCore
Hello,Might this possibly be a failure of a component on the the screen board instead of a more typical backlight failure? Let me know your thoughts.
That is not at all a bad guess.

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#1721766 - 03/18/21 03:27 PM Re: 1680 screen issues [Re: gyorpb]
DCore Offline
Planeteer


Registered: 03/02/20
Posts: 65
Loc: Washington State
I am probably gonna pass on this 1680. The seller notes that the VS-8F2 effect board(s) are not present. The recorder itself it priced fairly low but the effect boards are $70+ each and the replacement screen is $100+. By the time a person purchases the parts, the investment will far exceed what the repaired recorder will sell for. The beast is not cheap to ship either...$50-60...Ah well, I'll just go on scrolling...
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#1726240 - 04/17/21 12:56 PM Re: 1680 screen issues [Re: DCore]
DCore Offline
Planeteer


Registered: 03/02/20
Posts: 65
Loc: Washington State
Well, I let it pass...for awhile...until I saw it again recently. I messaged the seller and made an offer and he (she?) was able to lower the cost of shipping and the recorder. It looks like I am gonna have this project on my plate. I cannot create new effect boards, so I will have to find a set for a reasonable price. The display I can replace, having done one before. If the video board has failed, I might be able to repair it or replace it if necessary. All told, it has a "few" issues...On another note, I found that Boss makes a large pedal board soft-sided carry case that just barely fits the 1680. I discovered this because I bought one that the previous owner had transported in just such a bag. It is snug and is not a hard sided case like the Roland case but it works!
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#1728049 - 05/02/21 12:47 PM Re: 1680 screen issues [Re: DCore]
DCore Offline
Planeteer


Registered: 03/02/20
Posts: 65
Loc: Washington State
I received the 1680 and fired it up. The screen was fluttering and rolling like an old school TV with vertical hold issues. I tried replacing the screen first but the "new" screen performed exactly as the original one. I am now looking at the contrast board and wondering whether it could cause the symptoms described. The screen lettering is visible in between the vertical rolls and the recorder will load and play songs from the Hdd. I assumed that the picture of the screen was a static display picture. But the reality is, the screen is in constant motion. I did notice that the frequency of the motions seem to increase whenever the Hdd is being used/accessed. I do not have a conclusion based on that observation...just an observation. As of now, I am checking the contrast board, power supply and the Hdd.
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#1729016 - 05/07/21 01:38 PM Re: 1680 screen issues [Re: DCore]
DCore Offline
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Registered: 03/02/20
Posts: 65
Loc: Washington State
I opted to replace the contrast board with a NOS board. The issues still persisted. So far, the contrast board is new and the screen is known good. I am still seeing the lettering on the screen more clearly when the midi-hdd drive light is lit and the drive is working. I am wondering if I am chasing a power supply issue. I am thinking about unplugging the various boards (midi, effects, etc) one at a time and turning the recorder on to see if one or more of them is shorted and causing the screen to flutter. On a possibly related issue, I am very curious why the seller told me this recorder had none of the effect boards. But when it arrived, it had two effect boards installed. Anyway, the next step seems to be removing a board at a time and then looking more closely at the power supply.
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#1729121 - 05/08/21 01:02 PM Re: 1680 screen issues [Re: DCore]
MusicianJerry Offline
Space Cadet


Registered: 05/03/20
Posts: 21
Loc: Leeuwarden, The Netherlands
Hi there.

Maybe your machine, like some 2400/ 2480 machines, suffers
from bad electrolytic capacitors? Like in this topic:
http://www.vsplanet.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=1693567#Post1693567
or this one:
http://www.vsplanet.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=1441648#Post1441648

This can cause all sorts of problems. For instance, your problem could come from power rises and drops because the capacitors are not able to smooth out the power inconsistencies. Or just give wrong, too high or too low, voltages.
I, of course, don't realy know if this is the problem with yours. \:\)
But after the screen and board swap you did, which didn't solve the problem, it might be somthing to look into.
Some thoughts from a singer/ guitar player/ allround tinkerer.

Several people in those topics repaired their machines, or had it repaired.
_________________________
Greetings from Jeroen. aka MusicianJerry
aka The (street-)musician from Leeuwarden.

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#1729140 - 05/08/21 02:54 PM Re: 1680 screen issues [Re: MusicianJerry]
DCore Offline
Planeteer


Registered: 03/02/20
Posts: 65
Loc: Washington State
Thank you for your response! It is food for thought; that the capacitors on the power supply board or main board may be failing and causing voltage loss. I have a good deal of experience diagnosing and repairing tube guitar amps and E-caps are a regular replacement item. Perhaps I should look into refreshing the power supply board capacitors. The P/S boards I see on Ebay are all used which sort of concerns me. I may be buying a board with the same issues as mine! The prices are not very good in addition. The sellers want $65+ for these used boards. The price of capacitors is only a fraction of that. I will continue to pursue this mystery!
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#1730771 - 05/18/21 12:57 PM Re: 1680 screen issues [Re: DCore]
DCore Offline
Planeteer


Registered: 03/02/20
Posts: 65
Loc: Washington State
I am using the 1680 Service manual to troubleshoot this recorder. I am having difficulty deciphering the locations and voltages. So far I have:

On the main board- from power supply (CN2)
1)+15v
2)gnd
3)-15v
4)+5v
5)+5v
6)gnd
7)gnd
8)+12v

To drive pwr (CN3 )
1)+12v
2)gnd
3)gnd
4)+5v

If you can find test voltages other than these for the power supply and the main board, please let me know how to find them on the service manual schematics. I am specifically interested in voltages on the power supply board and the main board. Thank you!

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#1731151 - 05/19/21 06:43 PM Re: 1680 screen issues [Re: DCore]
DCore Offline
Planeteer


Registered: 03/02/20
Posts: 65
Loc: Washington State
I checked the voltages at the power supply board CN2 and then double checked them at the main board connection point, also labelled CN2...

schematic P/S Main board
1)+15v 14.9v +14.8v
2)ground 0v 0v
3)-15v -14.8v -14.8v
4)+5v +5.2v +5.1v
5)+5v +5.2v +5.1v
6)ground -14.9v +5.1v*
7)ground 0v +5.1v*
8)+12v +14.8v +12v

So, the voltages at the power supply seem to be in order, but somehow when they reach the main board the #6 and #7 pins (*) seem to be shorted out to the +5v supply on pins 4 and 5. I am gonna pull the main board and see if there is a physical fault in the CN2 connector. The CN2 connector on the topside of the mainboard is not removable. I wonder if it got tugged on a few times and caused the connectors to short out against each other. This may or may not be the cause of the video screen issues I am having. But either way, it can't be good to have a ground connection with 5volts DC on it.

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#1731228 - 05/20/21 02:43 AM Re: 1680 screen issues [Re: DCore]
gyorpb Offline
Planeteer


Registered: 05/11/19
Posts: 206
Against what did you measure?
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#1731329 - 05/20/21 01:32 PM Re: 1680 screen issues [Re: gyorpb]
DCore Offline
Planeteer


Registered: 03/02/20
Posts: 65
Loc: Washington State
Multimeter grounded at power supply ground and each pin measured for DC voltage. I measured the connector pins on the power supply board and the main board and compared the voltage readings to the information I gathered from the 1680 Service manual schematic. Is this the information you are seeking?
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#1731343 - 05/20/21 02:54 PM Re: 1680 screen issues [Re: DCore]
gyorpb Offline
Planeteer


Registered: 05/11/19
Posts: 206
Yes.

Did you test for continuity between the ground pins on the PSU?

The reason I ask, is this: you may know this, so sorry to lecture. A Volt meter measures potential difference, not some absolute value (as opposed to, say, a thermometer). If the black lead is at -12V, and the red one is at +5V, it will happily indicate a value if +17V. So establishing a proper ground is kinda important for your measurements to make sense.

All but those two grounds look fine, so you‘re probably doing a good job.

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#1731386 - 05/20/21 05:51 PM Re: 1680 screen issues [Re: gyorpb]
DCore Offline
Planeteer


Registered: 03/02/20
Posts: 65
Loc: Washington State
No offense taken, you bring up an important point. I was using the A/C ground point of the power supply board as my multimeter's ground point of reference. I will go back and recheck my readings. My attention was grabbed by the appearance of voltage (5.1v) where there should have been 0volts. I am at a loss to explain the appearance of voltage on the main board power connection on what is supposed to be at ground potential (0).
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#1731465 - 05/21/21 03:26 AM Re: 1680 screen issues [Re: DCore]
gyorpb Offline
Planeteer


Registered: 05/11/19
Posts: 206
I‘m wondering why the Vcc GND (pins 6 & 7) is kept separate from the AG GND signal on pin 2. unfortunately, the PSU is considered a black box and there is no schematic provided.

That you measured -15V on pin 6 and +5V on pin 7 is interesting; these are (should be) shorted together on the main board.

Did you measure with or without the power cable harness installed?

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#1731492 - 05/21/21 10:52 AM Re: 1680 screen issues [Re: gyorpb]
DCore Offline
Planeteer


Registered: 03/02/20
Posts: 65
Loc: Washington State
The voltages measured at the power supply board (CN2) were read without the connecting cable attached so I could access the pins. The main board voltages (also CN2) were read with the power supply board connected (as that cable is not able to be disconnected from the main board-it must be unplugged from the power supply board. Yes, pin 6 and 7 are shorted together on the main board after they are sent over from the power supply board where they were also kept separated. It is at that junction of pins 6 and 7 on the main board that I am reading 5.1v and I think it is supposed to be Ov (ground). I an wondering if the voltage from pins 4 and 5 on the main board (5.1v) has shorted over to pin 6 (and therefore, pin 7 also).
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#1731504 - 05/21/21 11:56 AM Re: 1680 screen issues [Re: DCore]
gyorpb Offline
Planeteer


Registered: 05/11/19
Posts: 206
Well, if C10 or C108 fails, that might well be the case.
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#1731595 - 05/21/21 08:43 PM Re: 1680 screen issues [Re: gyorpb]
DCore Offline
Planeteer


Registered: 03/02/20
Posts: 65
Loc: Washington State
My apologies for not reaching that conclusion sooner. Can you tell what value the C108 and C10 capacitors are? I see 10,000 (?)/6.3v in the parts list for C108 but no listed value for C10 either on the drawing or in the parts breakdown. I do appreciate your help here!
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#1731622 - 05/22/21 02:34 AM Re: 1680 screen issues [Re: DCore]
gyorpb Offline
Planeteer


Registered: 05/11/19
Posts: 206
That whole area of the schematic is befuddling. On the board itself, I only see C10 and R95. I don‘t have an actual 1680 at hand. What does the actual component say?
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#1731623 - 05/22/21 02:53 AM Re: 1680 screen issues [Re: gyorpb]
gyorpb Offline
Planeteer


Registered: 05/11/19
Posts: 206
Ok, the 5V Vcc line is the one of concern, here, since it is what powers the LCD Contrast Board. The +/ -15V lines strictly power the analog audio I/O; the 12V line only goes to the HDD (and thus sits unused on most 1680s, since 2.5“ drives only take 5V). There‘s also a separate 48V line from the PSU, but that‘s just phantom power and nothing else. I‘m betting on C10/C108.
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#1731679 - 05/22/21 02:01 PM Re: 1680 screen issues [Re: gyorpb]
DCore Offline
Planeteer


Registered: 03/02/20
Posts: 65
Loc: Washington State
I do not have the main board removed from the recorder. I have a picture or two of the resistor that feeds the two capacitors. I think the capacitors may be located on the underside of the main board. Can you clarify the size and voltage rating of the capacitors?

https://imgur.com/a/rHemI0N

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#1731696 - 05/22/21 03:39 PM Re: 1680 screen issues [Re: DCore]
gyorpb Offline
Planeteer


Registered: 05/11/19
Posts: 206
C10 is right next to 95. it is a rather small one. C108 is all the way on the bottom right of the board, near the diagnostic tool connector. That‘s the chunky one.
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#1731699 - 05/22/21 04:07 PM Re: 1680 screen issues [Re: gyorpb]
DCore Offline
Planeteer


Registered: 03/02/20
Posts: 65
Loc: Washington State
I see C10...C108 is a bit harder to identify. Check my Imgur pictures again...I have added a picture of the main board near the "test tool" connector. Is C108 the round one (identical to C10) next to the test tool connector? I can't see the printing on the main board...
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#1731701 - 05/22/21 04:27 PM Re: 1680 screen issues [Re: DCore]
uptildawn Offline
Planeteer


Registered: 12/15/01
Posts: 8899
Loc: on land
Not wanting to butt in, but is that a bulging cap in photo #5 at 11:26, or is that just the light reflection on the top of it?
_________________________
uptildawn

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#1731703 - 05/22/21 04:34 PM Re: 1680 screen issues [Re: uptildawn]
DCore Offline
Planeteer


Registered: 03/02/20
Posts: 65
Loc: Washington State
I think it's just the lighting (I do my own lighting, you know)...I will give all the caps a closer visual inspection.
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#1731794 - 05/23/21 02:01 AM Re: 1680 screen issues [Re: DCore]
gyorpb Offline
Planeteer


Registered: 05/11/19
Posts: 206
Looks like C14. C108 is a bigger one. Much, much bigger.


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#1731832 - 05/23/21 12:28 PM Re: 1680 screen issues [Re: gyorpb]
DCore Offline
Planeteer


Registered: 03/02/20
Posts: 65
Loc: Washington State
Thank you for isolating it...my eyes were going buggy from trying to find it. I have a picture of the main board I cropped and saved. It is a bit blurry but I think it shows C108-although it cannot be confirmed by the printing on the main board.
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#1731848 - 05/23/21 02:45 PM Re: 1680 screen issues [Re: DCore]
gyorpb Offline
Planeteer


Registered: 05/11/19
Posts: 206
Yeah, that‘s the one.
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#1733449 - 05/31/21 05:12 PM Re: 1680 screen issues [Re: gyorpb]
DCore Offline
Planeteer


Registered: 03/02/20
Posts: 65
Loc: Washington State
Main board removed-pics linked

https://imgur.com/a/C4FDYrl

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#1733576 - 06/01/21 09:56 AM Re: 1680 screen issues [Re: DCore]
gyorpb Offline
Planeteer


Registered: 05/11/19
Posts: 206
Nice. Two sidenotes:

C10 is a surface mount part. There are no solder points on the flip side of the board.

If you’re replacing C108, it is glued to the board (because it it a large part, and solder joints don’t take kindly to being stressed). You’ll have a hard time desoldering it without first detaching it.

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#1733608 - 06/01/21 01:15 PM Re: 1680 screen issues [Re: gyorpb]
DCore Offline
Planeteer


Registered: 03/02/20
Posts: 65
Loc: Washington State
I was looking at C-10 and wondering how to desolder it. I had a feeling it was mounted to the top of the board. I will amend my picture captions. I did note the glue blob at the base of C-108 and realized it would have to be removed before the capacitor could be removed. I am leaning toward replacing C-108 first and testing the board before replacing C-10. Do you think this is a wise approach? I would have to remount the board and reassemble the recorder to test it , so if C-10 was still bad I would have to do the whole process all over again. It would cost me time, but I have a bit of that.
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#1733621 - 06/01/21 02:41 PM Re: 1680 screen issues [Re: DCore]
gyorpb Offline
Planeteer


Registered: 05/11/19
Posts: 206
If I had the board out, I would replace all through-hole caps (and the input opamps, but that’s another story). Most of them are in the analog input section (near the input jacks). The surface mount ones, you can mostly get to without removing the board.
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#1737873 - 07/01/21 01:09 PM Re: 1680 screen issues [Re: gyorpb]
DCore Offline
Planeteer


Registered: 03/02/20
Posts: 65
Loc: Washington State
Update time:
I removed C-10 and C-108 and replaced them with new caps. I fired the 1680 up and the screen looked the same as before...rolling and fluttering as before. To recap, I have replaced the contrast board with new, and the screen with new, and replaced the capacitors C-10 and C-108 which were allowing 5v to leak to the ground pins. The voltages on the main board (from the power supply outputs) now test as follows:
pin 1 14.86v
pin 2 0v
pin 3 -14.86v
pin 4 +5v
pin 5 +5v
pin 6 0v (ground)
pin 7 0v (ground)
pin 8 11.86v

These voltages are very close to the schematic voltages. Replacing the caps was necessary because they were leaking 5v from pins 4/5 onto pins 6/7 which should be 0v (ground). So I will go onward from here checking voltages and looking for failed/weak components. If you have any thoughts as to where to proceed from here, by all means, share them! Thank you!

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