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joust

Member Since 02 Dec 2004
Offline Last Active Yesterday, 10:13 AM
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Posts I've Made

In Topic: D75 noise issues

13 May 2015 - 08:11 AM

I can't say that I've seen this problem before. However, take a look at the low voltage power supply and bypass caps. It is possible that LV may not be stable. (long shot!)
I've also seen some high value resistor (> 1Mohm?) being out of tolerance causing biasing of some circuit to be off.

A.

In Topic: The right amp for my Prx 418s

07 May 2015 - 07:44 AM

Very good observation! The IT6000 (3000W @ 4ohms St) delivers twice the rated power of the 4002 at the same load (1200W @ 4ohms St).

A.

In Topic: CTs 3000 clip channel 2

27 April 2015 - 07:44 AM

I would suggest that you get in touch with 'Kevin Heber' and ask for CTS3000 documents.

A.

In Topic: PSA-2

16 April 2015 - 09:27 AM

Verify low voltage psu : Make sure that the filters are filtering and that you have all the pertinent voltges : +/-15V, +/-20V
Verify high voltage psu : Make sure +/-75V is available to both channels; Make sure ripple is minimum.
Verify that C4 (8uf 250V) is within tolerance; It may be resistive!
Also, the fact that the 387 ohms is shorted out, you may have shorted driver or output devices.
You should have 5,6 ohms (+6 ohms in NPN) at BE junction on the output devices.

A.

In Topic: PSA-2

15 April 2015 - 08:13 AM

Since you've been able to determine that you have DC at the output before the relay disengages, it appears you may have a drive issue, a faulty driver or predriver, or more probable, an open low value resistor. I believe your output devices are probably OK, since you don't mention blown fuses or breaker.

I would also suggest, while you are at it, to remove and clean (if necessary) all devices in contact with the heatsinks. If you have mica type isolators below the output transistors, to replace the isolators with silicon fabric isolators.

Hope this helps!

Alain