CurtPalme.com Home Theater Forum

**Curt Palme** · Posted: Mon Apr 20, 2009 2:03 pm Post subject:

THey are fine, no need to measure them. An open cap would read something say under 1000Uf in order for the filtering to be noneffective at idle.

Leave the woofer spread all over the table, impress the company.

'You don't REALLY know what you're doing with this, do ya?'

'Why yes, I do, I took this subwoofer and modified it to be a foghorn, watch...'

'Ooohhhhhhh, Aaaahhhhh"

Smile

stefuel · Posted: Mon Apr 20, 2009 11:00 pm Post subject:

I have way to many projects going on at the same time this past weekend.

1. Work on this sub when time permits
2. Repaint the ceilings in my house TWICE this week. The first paint was mis-labled and I did the whole downstairs in one shot only to find out after it dried that I had used semi-gloss eggshell Rolling Eyes

3. Spend a half a day on the AmPro squaring it away
4. Be on-call Saturday for 24 hours for work related stuff.
5. Squeeze in some family time. Took them out to lunch today. (I was out to lunch before I left).

stefuel · Posted: Tue Apr 21, 2009 11:01 pm Post subject:

OK, I tested all the feedback resistors I could find. Best I can see IC3 has 2 (pins 6-7,51K) and (pins 13-14, 22K) and those are good.

IC1 has three (pins 6-7, 100K) (pins 8-9, 5.1K) and (pins 13-14, 5.1K) all those are good.

I guess the next step is to probe the outputs of the op-amps to see where the hummer originates. I'll have to check my stuff to see if I have whats needed to make the probe. Just what I need, another alien anal probe Laughing

stefuel · Posted: Sat Apr 25, 2009 10:31 am Post subject:

All right, I'm cought up at work, my projector is fixed (I can't believe I posted a AmPro problem and Pete hasn't peeped a word) and it's time to look at the amp again. I don't have a 10uf 100 volt cap. Does it have to be a 100 volt cap? I have a 50V in 10uf. I guess what you're telling me to do now is add that cap to the tip of the probe I was using to test for low level signal and use it to test for high level outputs in the amp section?
I don't think I need to test the input/filter board any further as it is outputting clean filtered sound to the power supply/amp board after trace repair.

stefuel · Posted: Sat Apr 25, 2009 9:36 pm Post subject:

There's somebody out on my roof and I think he means to jump.
I have a grounding problem and I can't find it. Gyv and I have been swapping PM's to no avail. I went back to the PC and blew up the image of PCB1 in the area that had all the damage and all the traces are accounted for. If I'm reading this correctly, I think I should be reading 10 ohms between the input grounds and the amps mounting plate. I show open line.
I have to quit for a couple of hours and go to a birthday partyI'll be back later to have another whack at it.

**Curt Palme** · Posted: Sun Apr 26, 2009 1:27 am Post subject:

A 50 volt cap is fine. All you want to do is route the output of each op amp to ground via the cap.

stefuel · Posted: Sun Apr 26, 2009 11:34 am Post subject:

Curt, just so you know where we are at at this time, I do have sound along with distortion coming from the neg side of the speaker output and a hum on the pos side. If I ground the barrel of the RCA low level input connector to the amp plate with a jumper wire, the hum goes away from the pos side and the distortion on the neg side goes away leaving clean adjustable sound varified with the probe setup. I have not tried a actual speaker connected to it while jumping the hot and cold grounds. R57 is supposed to do that. I tested R57 and it is OK.

Is this a lesson in electronics or a test of my sanity Laughing