CurtPalme.com Home Theater Forum

**Curt Palme**

So I've spent the day troubleshooting an Ampro 4200 that had an arc from the HV splitter HV lead that goes into the HVPS right to the convergence ribbon cable (!!!). It nuked the convergence board and hte CPU board, but it looks like I got that part running.

I am looking at the HV splitter now. It's the large (6" X 3" X 2") block that was similar to the one used in the late model Ampro 2600s, and it sits between the tubes. THe 4200 uses this block only as an HV splitter, so I am assuming that I can sub in a much smaller HV splitter as used in the 4600s? I don't see the need for having this massive HV splitter...

Thanks!

papalek · Joined: 08 Mar 2006 Posts: 1536 Location: Longs SC

Not really sure but my 4600s have that same large splitter. The 3600s that I have had all had much smaller ones. I myself do not understand the need for the larger splitters in the 9" machines when the voltage is the same for both.

tse · Joined: 03 May 2006 Posts: 1014 Location: Sweatbucket, Fl.

If the splitter has a ground lead then it has a filter network inside. If not, then it is just a splitter. Alot of video noise issues were blamed on the HVPS, hence the filter.

If you look on the bottom of the box you will see an ESP part number. That was the number for the empty box. I've seen that same box in other video projectors that had nothing to do with ESP/Ampro. I guess the company that molded the box sold them to any one that would buy them.

Scott

Ray Cendroski · Joined: 22 Apr 2006 Posts: 68 Location: Concord, Ohio

Not sure it matters, but my 4200 has a splitter block without a ground lead, and each of the three legs after the split has some large internal resistors in series to the three output connections.

My splitter had a corona arc around the outputs some years back, and I took out the old potting material and resealed it with fiberglass resin. Its been working ok since.

I never understood what the resistors were there for - maybe as current limiters in case of a short? I also don't know if maybe different resistance values were used for different tubes. Mine is an oddball with MEC tubes.

I guess you could easily compare the old block against the smaller block with an ohmmeter.

Ray

**Curt Palme** · Posted: Mon Jan 14, 2008 2:28 pm Post subject:

Thanks! I dropped in the small one and it seems to work fine. Now to get back to repairing the CPU and convergence boards. Seems that a 34Kv arc (multiple times) isn't good to data lines. 6 shorted chips so far and counting..

Why people don't turn off projectors when they hear arcing is beyond me. The HV lead had massive scorch marks on it, indicating that this was left in arc mode for a while.. Sad

Ray Cendroski · Joined: 22 Apr 2006 Posts: 68 Location: Concord, Ohio

Pretty much the same thing happened to me with a 3600 when the red tube anode lead shorted to the deflection yoke pins. It took out at least 6 IC's, mostly the major comm bus ones spread around the various cards.

I too was stupid and let it arc multiple times, after which it did the major damage.

I also found a burned surface mtd resistor on the CPU at the bottom of the board near the plug in connection. The 4200 might have something similar.

Ray

**Curt Palme** · Posted: Mon Jan 14, 2008 4:16 pm Post subject:

By chance does anyone have a spare 4200 CPU board and reggie board? 5 hours into this, and while I'm learning more about Ampros than I ever wanted to know, I don't know that I really need this knowledge.. Wink

Board swaps will be so much easier.

If Gary had ever sent me back my Ampro stuff, I wouldn't be in this mess.

tse · Joined: 03 May 2006 Posts: 1014 Location: Sweatbucket, Fl.

stefuel · Posted: Mon Jan 14, 2008 11:33 pm Post subject:

stefuel · Posted: Tue Jan 15, 2008 1:13 am Post subject:

e-mail sent

stefuel · Posted: Thu Jan 17, 2008 12:26 am Post subject:

Still waiting for those board numbers. Damn, I can't even give'em away Laughing