This page is dedicated to describing my "new" PJ, an Ampro Esprit 4200G which is a nice 9 inch, EM focus & Liquid Coupled CRT projector, performancewise it's in the best class of projectors, but it has a few problems that I've solved and described here.

  1. The green C-element is toast, I shudder to think of how hot the acrylic lens must have been to melt and bubble up like that, luckily it's relatively easy to fix.
  2. The C-element on the red tube is clear, which means that my reds are too orange, not that I notice, but as I'm going through the trouble of getting a new c-element for the green I might as well color filter the red one now I'm at it.
  3. The glycol in all three tubes has turned yellow and has gunk floating in it, so it needs to be changed, which is not too hard and as I'm changing c-elements on two of the tubes already it's not too large an overhead.
  4. It's noisy as hell, it's cooled by 3 sirens (2x 80mm and 1x 60mm), which also happen to move a little bit of air.
  5. It has a reputation for unreliability, because it's very hot. There are two small 80mm fans trying to combat convection and suck air through dense filters, which might be a good idea if the PJ is operating in a very dirty room in the artics, but it's a horrible idea anywhere else.
  6. The HVPS has the dreaded "top 1/4 of the image flickers/dims with certain scenes/brightness/contrast settings", this is caused by the G2 voltage sagging during retrace when the entire HVPS shuts down, the solution is to add a (or two) 10nF capacitor to the G2 output before the drop resistors and the zener regulator. See G2 the schematic
  7. It's slightly scruffy looking with a pc-beige cover, I'll remedy that cosmetic problem with a coat of black paint.

The cure for all the of the fanrelated trouble is to exchange the 80mm fans with low noise 120mm fans and replace the PSU fan (60mm whiner) with a papst 80mm, in general all filters and fingerguards will be removed, if people want to keep their fingers they will have to keep them away from my PJ.

The two 120mm belly fans have been mounted so they suck hot air out of the case and they don't have to fight convection.

The PSU fan has also been reversed, so it exhausts and to further aid cooling the PSU I have moved the 60mm fanguard to a new hole in the fuse-hatch, so the PSU can get air from inside the PJ.

The new fans have been mounted with weather stripping between themselves and the case and they are held in place with rubber bands to remove vibrations in the case.

To further help cooling of the convergence boards (the heatsinks get too hot to touch after a short while) I have also made a vent over the entire area with the heatsinks and covered it with 4 120mm fanguards.

I've uploaded a bunch of pictures here.

Vital statistics

This is a quick list of statistics for the Ampro compared to my old Electrohome ECP 3500:

FeatureECPAmproWhat it's good for.
ChassisDigitalDigitalBoth machines are menu-driven and very easy to set up once you have tried it a few times, unlike the old analog machines that were very hard.
CRT size5.5"9"Larger tubes mean better focus and more light, 5.5 is the smallest ever made, 9 is the largest except for very rare barco 912 machines.
FocusElectro StaticElectro MagneticEM focus allows tighter focus than ES and it is ajustable for different parts of the image.
CouplingAirLiquidWith LC there are no reflections from the lens to the tubeface that means that a bright spot doesn't leak onto the black surroundings.
Color filteringGlycolc-elements.Removes unwanted colors from the output of the tubes for more accurate colors, coloring the glycol doesn't work for LC machines, though.
Max resolution1280x10242000x2000The 4200 is being strange about the resultion it is supposed to be able to run at much higher resoltions than it wants to for me, I guess I need to tweak the modes.
Weight49kg80kgThe Ampro is much lighter than 80kg once the lenses are removed, yay.
OpticsUSPL Delta-HD6, plastic+acrylicUSPL HD10, aluminium+glass
TubesSony 07ms (+ sd187b)Sony 09MIThe 9 inch sony tubes are expensive as they cannot be rebuiltd and very few machines ever used them, luckily there are compatible MEC tubes that can be used in stead.

Shopping list

TODO list / progress

The two belly fans have been changed, the PSU fan has been changed and the PSU fuse hatch door got the 60mm fangrill.

The red, green and blue tube have gotten new glycol, the damaged green c-element has been changed to the fresh one from Graham and the red c-element has been exchanged with the new one from VDC.

The covers have gotten the 4 coats of jet black paint, it looks pretty bling bling with the golden wireguards I don't normally like shiny crap, but I have to admit I like the look.

It has been put together and when it has warmed up it's around 45 deg at the probe which is on a large capacitor near the center of the focus heatsink, which is the hottest part of the PJ.

I've been able to drop the peak temperature from 45°C to 39°C by blocking the two large holes that are on the outside of the red and blue tube, thus forcing more air past the top boards.

  1. Done: Dismantle machine in preparation for upgrades.
  2. Done: Cut new holes for the bigger fans (used a jigsaw).
  3. Done: Cut new intake holes in the cover over the regitration and focus amps.
  4. Done: Change Green C-element and glycol.
  5. Done: Change glycol on the blue tube.
  6. Done: Paint cover black as monday morning coffee.
  7. Done: Mount golden fanguards in top-cover holes for bling-bling.
  8. Done: Change Red C-element and glycol.
  9. Done: Put it all back together again.
  10. Done: Fixed the G2 dipping by adding 10nF to the G2 (against advice, it ought to be added before the drop resistors R26 and R7 in the schematic).
  11. Resolder the HVPS and change caps and power resistors.
  12. Modify the neckboards as pr. TFB #51.
  13. Modify the VIM and neckboards with low-ESR de-coupling caps.

Ampro 2000,3000,4000, 4200 service manual

I have the Ampro 2000 technical reference manual, but only on dead wood, I'm scanning it as I need it and putting up the pages here along with schematics from other sources (read: if you have any ampro docs, I'll be happy to host them here):

ampro-service-manual/1-8.png [1.3M] Description of CPU, Quad decoder, RGB 1 modules.
ampro-service-manual/1-9.png [1.3M] Description of Test/text, CRT Amplifier, Vertical Deflection and Horizontal deflection modules.
ampro-service-manual/1-10.png [1.3M] Description of H.O.T., LVPS, HVPS, Registration & Registration Amp modules.
ampro-service-manual/2-26.png [1.4M] CRT amplifier (aka. neckboard) schematics with TFB51 modifications inked in.
ampro-service-manual/2-28.png [1.2M] Vertical deflection module schematic.
ampro-service-manual/2-39.png [1.6M] SMPS module schematic.
ampro-service-manual/2-40.png [496K] SMPS regulator (80742X1) schematic.
ampro-service-manual/emfocus-sch.pdf [76K] Schematic of the Ampro 4200/2300 EM focus board (posted by tse to The AVS CRT forum in rajdudes valuable thread about his '4200.
HVPS-G2-schematic Schematic of the G2 part of the HVPS.
© Flemming Frandsen