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- Thread starter drpat
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Help Support GroupDIY Audio Forum:
Will the 990 tolerate +/-28V?
chrissugar
Well-known member
For me it looks like the cap is conected to +28V and ground.
I compared the footprint of the DOA with the picture of the PCB.
chrissugar
I compared the footprint of the DOA with the picture of the PCB.
chrissugar
chrissugar
Well-known member
By the way, any chance to do a reversing to the dead 1050?
It would be great because a lot of people are looking for this info.
chrissugar
It would be great because a lot of people are looking for this info.
chrissugar
chrissugar
Well-known member
I'm not sure if the 990 has, but most of the discrete opamps have integrated some ceramic decoupling caps. You should ask Fred, he designed those opamps.
You can add to the PCB, very close to the + - and GND pins two decoupling caps (one from + to GND, and one from - to GND)
chrissugar
You can add to the PCB, very close to the + - and GND pins two decoupling caps (one from + to GND, and one from - to GND)
chrissugar
chrissugar
Well-known member
I think before destroing that DOA it would be good to do some brainstorming with the guys who know about the chemicals involved in melting the wax. It would be a shame to not do this reversing properly.
chrissugar
chrissugar
What's broke? The op amp or the transformer?
Peter Purpose got his PhD in op amp melting, drop him a line.
Me, I would get out the heat gun and pick it apart with a dental pick.
Then when you get components showing, go slowly because you can melt solder and component labels if your over caffienated. Whatever, I never claimed to be a spelling B champ so lighten up Keef!
:grin:
Peter Purpose got his PhD in op amp melting, drop him a line.
Me, I would get out the heat gun and pick it apart with a dental pick.
Then when you get components showing, go slowly because you can melt solder and component labels if your over caffienated. Whatever, I never claimed to be a spelling B champ so lighten up Keef!
:grin:
chrissugar
Well-known member
drpat,
are you sure you connected correctly the wires to the 990? I always check ten times before I do something like this.
By the way you should use decouple caps for both + to GND and - to GND.
Probably the one for the - to GND in the HS1050 is in the wax and you can't see it.
chrissugar
are you sure you connected correctly the wires to the 990? I always check ten times before I do something like this.
By the way you should use decouple caps for both + to GND and - to GND.
Probably the one for the - to GND in the HS1050 is in the wax and you can't see it.
chrissugar
