CurtPalme.com Home Theater Forum

stefuel · Posted: Sat Apr 04, 2009 9:56 pm Post subject:

Sheeit, I don't have one and the closest rat-shack can come to it is .1uf or .22uf

Heywood Jablome · Joined: 12 Mar 2006 Posts: 1548

It's a radial and its .15uf?
I can check my cap collection at work, but in the meantime you can try the .22... Or you can come over and rape some of the dozens of spare barco boards I've got Wink

stefuel · Posted: Sat Apr 04, 2009 10:22 pm Post subject:

I'm gonna go grab the .22 after dinner. I have a pile of AmPro boards here to look at also.
Would you say that I tested it correctly?

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

Ahhh. so now your into the difficult part. No smoke yet i take it....

Well not sure why your checking C16 unless the manual is telling you that....but I dont see it. Also I dont know your cap tester. Have you verified your cap tester on other caps to see if its testing properly?

stefuel · Posted: Sat Apr 04, 2009 11:18 pm Post subject:

OK back on track. I was stupid for a moment The cap tested bad because I forgot to move the test leads from volt/ohms to ma/uf. The cap passes at .148uf. I need a bitch-slap with a baseball bat Rolling Eyes

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

Here's what I would do. Go back and check your +16v and -16v on those 2 diodes to make sure you have correct voltage. I would also recheck the +31v and -31v at those caps I suggested.

If your good there then you now have 2 options. Go to the output section and test the transistors and diodes for shorts. Page 24 in the manual also suggests that. The other option is to test the preamp output through another amp to verify you have that signal. The fun begins..... Smile

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

Oh, and if you want to test a cap then you should be checking C19, 0.47uf. That one is critical for preamp signal pass thru.

stefuel · Posted: Sat Apr 04, 2009 11:41 pm Post subject:

Off we go to check C19.
I'm not sure how much further I'll be able to go with this without a signal generator. The rest of the tests require a 100mV signal at 100Hz.

stefuel · Posted: Sat Apr 04, 2009 11:55 pm Post subject:

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

There's ways around not having a signal generator.

stefuel · Posted: Sun Apr 05, 2009 12:36 am Post subject:

More info,

Power feeding R2 = +35.45 and out of R2 = +19.54
Power feeding R3 = -35.55 and out of R3 = -19.64

Power across ZD1 = +19.41 with red on banded end -19.41 with black
Power across ZD2 = +19.40 with red on banded end -19.40 with black

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

Check voltages across D9 an D10. Should be in the 35 v range. if it is then I would check those transistors listed on page 24, Q4 thru Q15. Do you know how to test them? You can initially test them in circuit and your just looking for shorts between the legs.

stefuel · Posted: Sun Apr 05, 2009 1:07 am Post subject:

Both D9 and D10 are at 35.8V

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

Start checking them transistors then.

stefuel · Posted: Sun Apr 05, 2009 1:32 am Post subject:

Well I did check them thar transistors and found no shorts. While I was down there I probed the thermistor (TH1) and in circuit I show open line. I think I read something about it but can't remember. I must go back and see If I can figure out what TH1 taks out.

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

TH1 is part of the protection circuit. If the protection was active then the relay would unlatch. Th1 would also have high resistance, 100K. If the relay is latching and staying latched then TH1 should be non relevant.

Another thought, are the relay contacts good. Disconnect the speaker, turn it on, make sure the relay latches and check for continuity across the relay terminals for the speaker.

I think we are going to have to check the preamp signal. Do you have a stereo receiver and speaker to use for testing?

stefuel · Posted: Sun Apr 05, 2009 2:22 am Post subject:

Power off no continuity. Power on>click>continuity.
I did ohm out the woofer and it's dead smack in the good range.

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

2 more things to check before we go on. 1, go back and just make sure none of those 3 ic's you replaced are in backwards. Have done it myself on a few occasions. 2, check C24...47uf/35v. Another cap in line with preamp signal. If all is well then we need a stereo with a preamp input, like cd or something.

stefuel · Posted: Sun Apr 05, 2009 3:34 am Post subject:

All the IC's are in correctly and C24 tests to 50.2uf
I think I've had all the fun I can stomach for one night. I must clean the dining room table off before the queen gets home from work. For some reason, she doesn't think It's OK to have a soldering station and a bunch of hand tools on the dining room table Laughing

stefuel · Posted: Sun Apr 05, 2009 12:26 pm Post subject:

Boy this really sucks.
How is it that I can keep a AmPro running for six years but I can't make this subwoofer even fart a note Laughing