I got into the car this morning and half of my display was blank. Memory told me it was this problem, but after doing some research, I don't think it is.

The difference is that the half of my display that's blank is interleaved with the half that works right. That's right, I've got stripes! Vertical stripes, to be specific. About a dozen on-stripes and a dozen off-stripes. Anyone have any ideas?

Does this appear when booting also? (initial tux image) Possibly a reload of firmware and getting rid of any custom applications might help. But that is only if the problem is software based. You might want to try loading a clean copy of 2.0 final without any add-ons, just to verify. If that does not help, then it is a matter of looking at hardware...

Yeah. It's 100% of the time. And Trevor brought up offline that I might have blown a display fuse -- the garbled display thing -- but I haven't so much as opened the empeg case in months, so it's not like I just recently plugged in the display cable off by one or anything.

The display fuses have been reported to just blow on their own from spike to spike..

I'll give it a shot, then. Good excuse to buy myself a decent multimeter.

I think that the actual Noritake display glass has failed. The glass itself has column and row drivers and they can occasionally fail. I have an Empeg I am working on right now with the same problem. I am trying to get a pinout of the Noritake MN12832E to verify but I fear that it will need replaced.
If anyone else has any additional info I would love to hear about it.

Nick

Well, at the very least, it's not the fuses. Checked all three I could find on the mainboard (two just above the display connector and one below) and they were closed.

I took some pictures, if anyone wants to see.

Yup, looks like something went dead.. probably in the display tube itself.

Cheers

Can someone measure the capacitance of the two big capacitors on the back of the display board? I may not be reading it right, but I think the one closer to the other big component (whatever it is) is bad.

Eh. It's not the capacitor. Must be something wired in parallel with it that's causing an on-board test to be different between the same capacitor on two different boards. Almost everything else on the display board looks to be an IC, so little chance of me testing it out. If everyone else thinks that it's the display itself, then I suppose it's time to get one from Paul. <sigh> You get money, it goes right back out the door.

Greetings!

You rang? I have a few spares for just this kind of thing. If you need one, drop me an email with details (shipping, etc.). Thanks!

Hi Paul!

The display of my Empeg has the same symptoms as descriped in this thread...vertical stripes all over the display. It's really hard to read anything and so it seems I have to replace the display. Do you still have spare-parts and what's the price for them?

Greetings from rainy Austria

Michael

Greetings!

I still have a few VFDs stockpiled for emergency use. Please sent me an email with full shipping details. The cost of the VFD is $65, which includes shipment to what sounds like rainy Austria...

This happened to me again.

Does anyone know what might cause this to be a reoccurring problem?

Again?!?!

At this point, I could only guess that there is a fault on the display board itself, or that too much power is somehow being fed into the VFD. I am not sure how it could happen, but hopefully someone else here will have an idea.

The bad news is that I do not have any VFDs left - not even a personal spare. It looks like I might have to put a call in to Noritake if the glass is bad.

I believe I have 2 spares currently, I can part with one for him if you're out.

Thanks, Derrick. I think I'm going to wait and see if someone can come up with a reason that this is continuing to happen rather than blow out another one.

I have 6 new, one second hand here. Don't worry about stocks - I have about 100 damaged repairable displays (both Mk 1 and Mk 2/2A), a great deal of which simply have component failures. The stuff isn't cheap, I'm afraid, but it is available and I am selling the stuff on at cost price to make sure the price stays as low as I can keep it. I am likely to be buying a batch of stock sometime in the next few months.

As for the problem with the display - the interleave problem is a failure of one of the raster controllers inside the glass. It can manifest itself as either a low voltage from the power supply from the display board (under about 48 V) or as a result of the tube getting a bit gassy. You can check the first with a voltmeter (probe the lead of the large black capacitor nearest the inductor on the right hand side of the display as you face it, on the back of the board). You can see the second (look in the display glass with the lense removed at the corner near the nipple and look for a light, white-coloured deposit on the inside of the glass - like mist). The first can usually be sorted out by repairing the power supply, the second is not recoverable

Okay. Pretend I have a multimeter but that I have no idea where to stick the pointy bits. I gather that one end should be at that cap you described (either side's lead?), but where should the other go?

Also, are you saying that problem the first is that the empeg's power supply might be marginal and it's causing it to blow the tube (or that the tube's not actually bad, but just not being powered properly) and that problem the second is just a bad tube? Given that I've had two go bad, and not too many people have complained about that, the probability is that it's problem the first, right? I mean, I'll still check it, but if you have some definitive notion that that's the problem, especially given that it's reparable, that'd be super.

Exactly like that

Set your multimeter to the DC voltage scale, range 60V.

Take the black lead and attach it to the case metalwork.

Take the red lead and do as follows: locate the two black electrolytic capacitors (they look like black tubes about a centimetre long with a lead coming out of each end) on the top rear of the display board. Touch (carefully) the capacitor lead nearest the inductor (the tiny black rubber tube sticking out of the board). Be careful NOT to short either probe against anything else - don't do this if you're pissed (or even just plain tiddly drunk)

You should read something like about 56V, max 63, min 46.

A little further explanation: the empeg has one main power supply on the motherboard. This produces a number of different voltages, 3.3V for the processor and RAM/FLASH, 5V for the peripheral devices (USB, Ethernet, IDE, Sound, etc), 10V (analogue, etc). However, it does not produce the high voltage needed for the display board.

The motherboard feeds three voltages (3.3, 5 and 12V) to the display board, with three in-line fuses. On the display board is a tiny switch mode DC-DC PSU that generates the required 60V HV for the tube (and therby conveniently localising it in the display board assembly for safety/isolation).

If this PSU goes a bit feak and weeble, then it looses the ability to drive the VFD properly and the tube starts to do weird stuff. Hence, yes, some tube faults are not necessarily a failed tube. However, if the tube looses vacuum, then it's knackered.

You need to measure the voltage first. I will post images after this post showing how to probe the display voltage.

I'm not anywhere useful right now to do this stuff, which is why I keep asking these questions without doing anything.

Are you saying that the power supply that you'd repair would be something on the display board itself? If so, I've had this problem with two different display boards, which also seems odd. Is it possible that the power coming from the empeg mainboard is off? That would make the most sense to me.

Here's a picture of how to probe the empeg display voltage (thanks to my lovely assistant).

Note the black lead is toucing the screw head on the main board that is the earth for the board and is screwed into the chassis.

The red lead is touching the cap lead, shown in more detail on the next picture.

PS The small chip on the paper in the background will be the subject of a post in the near future. Watch this space

This picture shows the point where the HV is measured for the display board.

Note also the two mods I usually apply as part of a service on 2/2A displays: hot glue under and around the inductor body to stop it being broken off during disk tray removal (don't laugh - you won't when you break it off yourself). The second is the dimmer glitch fix - the SMT capacitor across the two middle legs of the dimmer controller.

Okay. I read 1V there. Yes. One.

Oh, wait. The display was off when I checked it. 45V, and slowly rising.

What's next?

Well, it's a bit low. The "ideal" voltage is 60V, but it usually measures up at about 56V. At around 10 - 15V down, the display tube could be unhappy.

Have you got another player you can measure for comparison?

Curiously enough, I have just measured my own test unit and it's only showing 48V. Hmmmmm...... I need to consult the oracle.

Not really. I can finish fixing my old display board and put it in my backup empeg. Despite using it for months, this display went bad within a week of putting it in my primary unit. The primary unit also, I think, needs the DC adapter replaced, as it comes on by itself in the car. Could continuous power cycling have anything to do with anything?

I have more data! It's not the tube. At least I don't think so.

This morning on the way to work, my display seemed to get dimmer. I think it actually did, but it could have just been a change in ambient light. Regardless, I went into the dimmer settings and lowered it all the way down, which is something I'd do before I installed the cap to fix the non-linear brightness control thing. When it got down to 30%, which was barely visible, the other half came back on. When I brought it up to 40%, the other half blanked out again. Weird.

I did attach a cap to the IC on the back of the display board and this seemed to fix the brightness adjustment linearity problem. However, it was not a SMT cap, but a throughhole ceramic disc cap. Would that make any difference? The specs were the same as the SMT cap suggested inthe FAQ, and I did not make this change to the display board that previously had this same thing happen.

Actually, sometimes 40% seems to be okay, other times it shows my problem, and still other times, it shows the problem about halfway.

In the latter case, some of the off columns are lit and others are not, usually in clusters. Sometimes some of the columns flicker and some are lit. Sometimes all of the affected columns flicker.

There's obviously some threshold problem.

Also, there now seems to be no difference in brightness beween the 70%, 80%, 90%, and 100% settings. This may explain the perceived dimness this morning.

Okay. More information. Sometimes, and I have no idea what defines those times, the screen, when normally in a brightness area that would show both sets of columns, will ghost, as if it's having bad OTA reception. It's hard to make out exactly what's going on, and I haven't caught it at a time when I can take a picture, but it appears that the always-on columns are being repeated in the sometimes-on columns to the left, opnly dimmer. I want to say that when this happens that the sometimes-on columns are also showing the correct thing in addition to the ghost.

This really sounds like a defective VFD, I'm afraid.

I'd be happy to replace it, but if it is a defective VFD, then it's the second one I've had that's defective in that unit. I don't want to put another one in and have it burn out, too.