Eventide H3000 general service

I've got an H3000 on the bench.  At first it had some intermittent noise issues on the left channel.  That was fixed with re-seating the opamps on that channel.  I noticed it had a level mismatch between the channels (not much...0.6dB, just enough to annoy me).

To isolate that issue, I did a reset of the unit, created a patch with the noise generator sent to both outputs, and turned the input all the way off.  The levels were the same on both outputs so I ruled the output side out as an issue.  Unfortunately the copy of the service manual I have is missing part of the input section.  I watched the output with a spectrum analyzer in the DAW and also a scope and set the offset and  distortion pots.  The left channel is lower in level no matter what I do.  It's also noisier than the right channel.  I'm wondering if the Murata filter on the left channel is a bit off.

LCD Backlight is kinda dim.  The +5v is good, so I'm thinking dropping R23 on the front panel PCB should do the trick (currently 5r6, I'll try 3-4r or so and see how that goes).

I checked through all of the suggested updates in the service manual.  They're all implemented so nothing to do there.

I plan on replacing the PSU electrolytics, upgrading the ROMs to "kitchen sink," and replace the battery/RAM module.

Anyone know where to get case screws for this thing?  Any other things I should look at?

Thanks!

Before you mess with the VF display, make sure you adjust the contrast setting. I forget where it is, but it's in some system setting page. I was working on one recently, and the display looked really awful until I properly set that parameter.

Clean the Molex PSU connector on the PCB. Or even better cut it off and solder the wires directly to the pins. These connectors usually suffer from heat over time and get "browned". Your display backlight problem may come from that source.

TheJames said:

LCD Backlight is kinda dim.  The +5v is good, so I'm thinking dropping R23 on the front panel PCB should do the trick (currently 5r6, I'll try 3-4r or so and see how that goes).

Click to expand...

A known issue with the LCD is that the intensity changed with the loading of the equipment. This was cured by running a separate ground wire from the power supply.

Thanks guys!  Great input as always.

I've adjusted the contrast...For the H3000, you can hit "function" and then just turn the wheel to adjust it.  While that can make it more legible at different view angles, it's still not particularly bright.

I tried the ground thing...No difference.

I looked into the level issue further.  Just before the Murata filter, I measured a descrepancy in levels between L-R channels.  On page 73 of the service manual I have, I noticed there's a "optional" resistor (R60) listed as a L-R level match.  It's (presumably) an off-board parallel resistor to R46 (no place on the PCB for it).  If they new this might need adjustment, why didn't they make R46 a trimmer??  Anyway...I tacked some leads on a trimmer and replaced R46.  L-R  levels track, LED meter's track, Life's good.

I noticed that Studio Electronics has a complete overhaul for the H3000:

"We service all versions of the H3000 and H3500 and can update the program chip sets. Typical service cost is $615.00. This is a labor intensive servicing that includes power supply recap, cleaning any intermittent soft key switches, power supply connector replacement and upgrade, replacement of the NVRAM battery backup IC, cleaning the inside window of the alphanumeric display, internal adjustment of display brightness (if needed), other minor repairs that may be needed, and calibration of the offset and distortion trims. Upon completion, we do a complete 108 point check out of the analog and digital sections using Eventide’s proprietary H3000 test software, replace any missing or damaged chassis screws, and use a paint pen to touch up scratches in the black areas."

I wonder what they're using as a replacement connector for the Molex?
I wouldn't mind getting my hands on that test ROM either.

Any thoughts on the screws?  This thing has been serviced at least once before (different ROMs, replaced voltage regulator, replaced opamps) but somehow it didn't keep all of it's screws.  I suppose I can contact Studio Electronics and see if they'd hook me up.