CurtPalme.com Home Theater Forum

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

Oh, and make sure you order an extra socket for IC3 too. Its also in that 16v circuit....

stefuel · Posted: Fri Apr 03, 2009 9:35 pm Post subject:

Well I'll be dipped in $hit. I changed Both IC's on board 2 along with adding sockets for future service. I also replaced the two zeners suggested in the manual and I still have high voltage across R2 and R3. I'm getting about 31.5V it should be 11-14VDC. IC3 is not indicated in this condition but I may as well swap that next as I did buy extras.

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

Actually it depends on which side of R2 and R3 your testing.On one side it should be 31v and the other side 16v. Where to you have your test meter gnd connected?

stefuel · Posted: Fri Apr 03, 2009 10:08 pm Post subject:

The manual says to test "across" so I took that as testing at both legs of the resistor.

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

Here's what to do. Start with ZD1. Locate the stripe on it. take your volt meter and put the positive leed on the end of the diode with the stripe and the negative leed on other side of the diode. it should read 16v. Then go to ZD2, locate the stripe and this time put the negative leed on the side with the stripe and the positive leed on the other side of the diode. it should read -16v. What do you have?

Also is the relay clicking when you turn it on?

stefuel · Posted: Fri Apr 03, 2009 10:36 pm Post subject:

No relay click. I can get at one of the zeners but will have to move the transformer to get at the other. Also, I noticed that the output of the transformer is a little high at 24.5 VAC out from both blues. It's supposed to be 22VAC

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

stefuel · Posted: Fri Apr 03, 2009 10:59 pm Post subject:

Diode check
+1.25
-1.35

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

Ok, we need to back step a little first to see whats going on. Locate C5 and C6. Should be the large caps. Identify the + side for each on the back of the board. Now take your volt meter and on C6 put your positive probe on the + side and your negative on the other cap pin. You should have +31v dc. Now go to C5 and put your negative probe on the + side of the cap and the positive probe on the other side of the cap. You should have -31v dc. If you dont then remove R2 and R3 and retest voltage at C6 and C5. Wadda ya got?

stefuel · Posted: Sat Apr 04, 2009 12:12 am Post subject:

By Golly, I think it's working. I got PO'd and pulled it apart again to changed the remaining IC. I have clickage and close to listed voltages Very Happy

stefuel · Posted: Sat Apr 04, 2009 12:14 am Post subject:

Also there may be a type-o in the manual as the remaining IC is also listed (on the main board) as IC1.

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

So is it shaking the house? Very Happy

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

stefuel · Posted: Sat Apr 04, 2009 12:54 am Post subject:

Not shaking yet. I need to run a line level connection to the theater from the rack location, Install the amp back into the cabinet and repair a broken foot that happened durring shipping.

Look at page 34. The drawing on the right, as does the PCB it's self, is clearly marked IC1

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

stefuel · Posted: Sat Apr 04, 2009 1:38 am Post subject:

"Even the Ampro service manual has an error in it.... "
Say it ain't so... Not that anyone would ever have the need for it anyway. Mine is collecting dust.

I put the amp back in the cabinet and plugged it in. It's alive for sure. It will be thumping by noon.
Now I have to go to the kitchen table and put all my soldering equipment and tools away before the wife gets home and sees what I've been doing on the dining room table.
Thank you for your help. I'll let you know how it works tomorrow

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

Your Welcome Thumbs Up

stefuel · Posted: Sat Apr 04, 2009 10:55 am Post subject:

I don't fully understand the "servo" sub thing. It's kind of freaky when you turn this thing on. The manual does make mention of "breathing" when you first turn it on. When you flip on the switch, there's a couple of second delay, you hear the relay close and if you have the grill off, you will see the driver slowly fully retract then fully extend then go to mid-point. You don't have to look hard to see it as the amount of travel durring the breathing stage is about a inch.

stefuel · Posted: Sat Apr 04, 2009 9:30 pm Post subject:

Well damn, it powers up but no output. I'm back inside to check C16 on the input board for failure. I have tried it with both high and low level inputs with no output. The good news is, there isn't many steps for testing once the relay is powered up.

stefuel · Posted: Sat Apr 04, 2009 9:49 pm Post subject:

My dmm has the capability to check capacitors. I removed C16 from the input board. It is a .15uf 50V polyester film radial lead. However tha manual lists it as a 100V. Anyway, I set my dmm to the lowest setting (4uf) and tested it both ways and nothing. Checked continuity and it's open both ways. Have I checked it correctly?