Rockford Fosgate Power 650

[seankane]

Just scored another 25 D41D8 transistors from a gentleman in Canada at a very good price.

[shawnk]

Originally Posted by Perry Babin

You now need to test it with a load (all transistors clamped, fan not necessary because you need it to heat up). Let it heat up about 10° and see how the idle current has changed.

Done! I just drove the amp (both "repaired" channels 4 ohm load each) with a sinewave for a good 20 minutes and let the amp warm up significantly.

The amp drew ~1.5A at idle when first fired up (cool to the touch) and after the 20 min run, current draw only icreased by ~0.25A. So even when warmed up idle current was still less than 2A. After the run, the output pins for each op-amp remained clean/flat and there was no more dc offset present.

This is all great, but I'm just wondering why the amp is acting differently than my previous testing. I haven't done anything different to it other than present a load.

Thanks

[shawnk]

Originally Posted by seankane

Just scored another 25 D41D8 transistors from a gentleman in Canada at a very good price.

Nice score!!!

[seankane]

DC can do wierd things in these old amps. Sometimes these amp are stable and sometimes they are haunted....lol!!!

I have 2 brand new bottom covers for these amps and I noticed you had a green board version which was the last models before they were discontinued. My 4 power 650's were all the older models with the DIN which I removed and replaced with RCA jacks of course.

The selector switch for 4 channel and 2 channel must be different on the later models, like a very small switch. The hole in the sheet metal I have is very small and cannot accomedate the older version slide switch.

I was wondering if you could post a pic of the switch on your board and the bottom cover where the switch comes through???

[seankane]

Just scored another 250 D40D8 transistors for a good deal.

[shawnk]

Originally Posted by seankane

DC can do wierd things in these old amps. Sometimes these amp are stable and sometimes they are haunted....lol!!!

I have 2 brand new bottom covers for these amps and I noticed you had a green board version which was the last models before they were discontinued. My 4 power 650's were all the older models with the DIN which I removed and replaced with RCA jacks of course.

The selector switch for 4 channel and 2 channel must be different on the later models, like a very small switch. The hole in the sheet metal I have is very small and cannot accomedate the older version slide switch.

I was wondering if you could post a pic of the switch on your board and the bottom cover where the switch comes through???

Sure man. I'll snap a couple pics in the morning for you.

I have two of these 650's here. One "newer" one has the green board and the shroud has the larger 4" fan.

I also have an older one which is the one giving me a hard time

[shawnk]

Pics for Sean! Let me know if you need any others bud...

[seankane]

No thats perfect, the bottom covers I have are still different. Maybe they were a defect?

Where the 2 channel/4 channel switch is it is a very small opening. Maybe like they were going to give the 650 a facelift an modernize it a little then came up with the DSM's and bagged it.

These are brand new bottom covers. I could modify them to work, be nice to find a switch that would work with the slot that is cut ya know?

[Prime mova]

Sean, give us a few pics of these bottoms.

[shawnk]

Originally Posted by Prime mova

Sean, give us a few pics of these bottoms.

yeah.... please do. Inquiring minds want to know