Orion 280GX amp repair

thegmann

Member
2008-02-15 4:10 pm
I have an Orion 280GX that needs repair. The left channel appears to work properly. The right channel makes sound, but while adjusting the right gain, there is an extremely loud pop from the speaker. The pod is also extremely difficult to turn.



Please help.
 
Do you have a pod in spare ? I´d suggest you replace the pod, for testing purposes you can use a regular pod from the tinkerbox (but the value should be in the same range! also if it is a stereo - pod insert two regular resistors in the other channel´s pod - holes) If the popping sound disappeared get a new pod for the amp.
 
another very very cheap trick is to spray some WD-40 on the pod (if it is an open designed pod where WD-40 can enter inside, otherwise the "trick" wont work) . But that will only last for about 2 or 3 turns. If the popping sounds are gone replace the pod with a new one! Also make sure you clean up the WD-40 mess around the pod instantly on the curcuit board as some curcuit boards are paper-based and swell very quickly.
 

thegmann

Member
2008-02-15 4:10 pm
I checked the pod solder joints and also tried the WD-40 trick, unfortunately neither fixed the popping problem. I'm pretty sure the problem is with the pod, like you suggested, because it is possible to over rotate it.

The pod has Piher 25K 248 written on it.
What would be a suitable replacement for it?
 
That a great question. I am using 280GX in that same application to power midbasses between 100-250hz.

I know that the Orion HCCA's are considered incredible amps for bass and midbass application and they are very similar to the GX series amps.

Are there any modifications that can be done to the amp to improve performance for midbass applications?
 

thegmann

Member
2008-02-15 4:10 pm
Thanks for the earlier help guys.

I have just gotten around to replacing the pods.

When I took the board out of the case I noticed that the foam tape on the under side of the clamp was broken in a few places. None of the breaks are directly over a fet. (see the included pic)

Does the foam tape need to be replaced?
 
Pods = pots (potentiometers)?

I'd replace the tape but if it's perfect where it mates to the transistors, it probably won't make a differrence.

If you do, you have to run the amp long enough to get it hot. As it warms up, you need to tighten the clamp screws several times (5-10 minute intervals depending on how hard you're driving it). You can't tighten them enough (all at once) to prevent the clamps from getting loose without taking a chance of stripping the holes.

If you replace the tape, don't remove the backing. This will prevent the tape from sticking to the transistors and will make it easier to take the amp apart if it fails again. When you remove the tape, you must get all of the old tape off before applying the new tape.