Test Gear Maintenance: LCD Display Issues on Analogic 2030 Multifunction Waveform Synthesizer

[nevetslab]

I have this unique Analogic 2030 Waveform Synthesizer which has a large LCD screen on it's front panel which has horizontal lines across it that don't belong. This is the last of the three units I had owned, having repaired and sold the other two back in 2011 & 2012, keeping this one, having finally succeeded in repairing the power supply. The instrument IS functional......just has these unwanted horizontal lines appearing on the screen and thus far, I don't know if this is a permanent defect in the display, or if it's from the controlling circuitry or even connections. When I was first investigating this, I still had one of the one other instruments, and swapping screens, the problem moved with the front panel / screen PCB assembly. That may rule out interconnects, as far as two instruments were concerned. Still could be connector issues on the defective screen assembly.

Anyone out there with experience on troubleshooting LCD screens like this? I do have the service manual, though the reproduction quality is pretty poor. Analogic hasn't been in the Instrumentation business now for a good 10 yrs or more, so no replacement parts available nor factory support.



I had dialed up a Phase Modulation waveform, using 50Hz @ 1V RMS (1.414V Pk), with 45 deg Phase modulation at a 4Hz rate. Scope photo shows the modulation character. The last image shows what the LCD Display should look like....this one being from one of the other instruments I had sold.



Analogic _2030_Data Sheet.pdf

[glebert]

Does it have an actual connector on the LCD, or is it more of a permanent connection? I remember on a Saab my wife had the display for the radio had lines like this, and it was a known issue that would happen to those cars. They had used a kind of thermal formed foam to push the ribbon cable against the board, and it would shrink over time and some lines would be lost. IIRC the fix was to use a heat gun to soften the foam and push it down until is rehardened, but there was a chance of loosing the whole display so I never did it.

[nevetslab]

Does it have an actual connector on the LCD, or is it more of a permanent connection? I remember on a Saab my wife had the display for the radio had lines like this, and it was a known issue that would happen to those cars. They had used a kind of thermal formed foam to push the ribbon cable against the board, and it would shrink over time and some lines would be lost. IIRC the fix was to use a heat gun to soften the foam and push it down until is rehardened, but there was a chance of loosing the whole display so I never did it.

There are two ribbon cables. I haven't been inside it since late 2012, so kind of starting over. On one of the other displays, I had replaced the eight 4.7uF/35V radial electrolytic caps laid over on their sides, and have that task yet to do. I'll have a closer look once I pull this apart again. I do see twist-tabs used to hold the top PCB assembly into place, so there may well be some friction-held connections in this assembly. I've had this powered up for a couple hours, and during that period, the display has cleaned up a little bit, though the upper blue line is still solidly in place where there shouldn't be anything.

[g1]

No elastomers or 'zebra strips' between the display and board, like is often used for DMM displays?

[nevetslab]

No elastomers or 'zebra strips' between the display and board, like is often used for DMM displays?

I don't know yet......I left off at replacing the eight tiny 4.7uF/35V electrolytic caps on that top display PCB assy. All of those original parts had corrosion on their leads, with one having puked white stuff onto the solder pad. I debated at that time to untwist the metal tabs around the perimeter of the PCB and carefully lift off the board. I do see a foam liner around what looks like cushioning for the glass housing. The schematic lists this display as florescent, and it has 225VAC applied to it. I ended up NOT opening the tabs and digging deeper at that time, and checked to see if anything changed after replacing those caps. Didn't change the display defects...the lines are still present. I set it aside for the moment, as more paying work came in. Always something to interrupt fun time. So, I'm not yet thru digging for a solution. Just hope opening it up doesn't screw the pooch.

Thanks for the suggestion.....I've seen that zebra strip on both the Fluke 8060A displays as well as on my HP 41CV calculator.

Digging further thru the service manual, all of their 'troubleshooting' guides suggested was replacing complete PCB assemblies. Typical. Turns out there isn't any documents/drawings for the Display PCB assy at all. I was able to slightly change the lines by messing with the 20-cond ribbon cable, but not enough to tell me I have bad cable/IDC connections, or (heaven forbid) PCB pin solder joint issues with multilayer board. Don't know for sure if these boards are multilayer, but, it wouldn't surprise me. When I do pull it further apart, I'll replace that display ribbon cable with a freshly made one, just in case.

[Helmholtz]

The schematic lists this display as florescent, and it has 225VAC applied to it.

This indicates a VFD ( https://en.wikipedia.org/wiki/Vacuum...escent_display ) rather than an LCD. It's actually an electron tube.

[glebert]

This indicates a VFD ( https://en.wikipedia.org/wiki/Vacuum...escent_display ) rather than an LCD. It's actually an electron tube.

Great, now we have to get into the tube vs. solid state thing...

[Garrstim]

I just acquired an Analogic 2030. When powered ON all user adjustments respond to commands, but when OUT is pressed an error notification appears in lower left of screen : ANALOG OVERLOAD. Does your service manual mention what this means and what to do about it? I've not yet looked at the output with scope.

Also, the User Manual is readily available, but I have not found a Service Manual although I have searched deeply. Can you direct me to your source for the manual or could I get a copy of yours somehow?

The 2030 has formidable capabilities and I would be quite happy if I could restore it to proper performance or somehow eliminate the source of the system complaint message.

Thanks very much for any response.
Barry

[nevetslab]

I just acquired an Analogic 2030. When powered ON all user adjustments respond to commands, but when OUT is pressed an error notification appears in lower left of screen : ANALOG OVERLOAD. Does your service manual mention what this means and what to do about it? I've not yet looked at the output with scope.

Also, the User Manual is readily available, but I have not found a Service Manual although I have searched deeply. Can you direct me to your source for the manual or could I get a copy of yours somehow?

The 2030 has formidable capabilities and I would be quite happy if I could restore it to proper performance or somehow eliminate the source of the system complaint message.

Thanks very much for any response.
Barry

I seem to recall having that message appear from time to time when the instrument wasn't yet fully functional. I forgot to look thru the Service Manual for reference to that message. I just got your email, and sent you the Service Manual,

Analogic 2030 Hardware Maintenance Man. PN82-7070 Rev.0(Preliminary) 1993-01 w-txt.pdf

Analogic _2030_User-1.pdf

Apparently when Analogic left the Instrumentation Equipment business for more lucrative horizons, Rhode & Schwarz had secured the right to continue manufacturing this instrument.



I also have an Analogic 2020-100 Polynomial Waveform Synthesizer that I haven't gotten back to tackling. As I recall, there's discontinuity in joining one sine wave with the next one and next one in the normal continuous stream that we always see from an oscillator, rather than from a device that creates it digitally. I never got past Calculus....kinda crashed and burned there, but one would need those skills to program the 2020 and have it create waveforms from the equations from the front panel, or from the program you write to run it from. Tucked away in storage is also a 2020-25 that needs to be restored. I have the original Service Manual and Operators/Programming manuals for it.