Home |
Search |
Today's Posts |
|
Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
Reply |
|
LinkBack | Thread Tools | Display Modes |
#1
Posted to sci.electronics.repair,uk.rec.audio
|
|||
|
|||
Mission amp schematics ...
Anyone by any chance got a set of schematics for a Mission Cyrus amp to hand
? It has a small DC offset on one channel. Not large, but enough for the protect circuitry to see it as a problem. Unfortunately, I am seeing lots of tantalum bead caps in it ... :-( Arfa |
#2
Posted to sci.electronics.repair,uk.rec.audio
|
|||
|
|||
Mission amp schematics ...
Arfa Daily wrote:
Anyone by any chance got a set of schematics for a Mission Cyrus amp to hand ? It has a small DC offset on one channel. Not large, but enough for the protect circuitry to see it as a problem. Unfortunately, I am seeing lots of tantalum bead caps in it ... :-( Arfa No, but I did have an alarming offset incident with my Cyrus 2 about 5 years ago. I was about to sell it to this girl I knew, so I got out a damp cloth, and gave the top and sides a good rubbing to remove the dust, before she came round. I'd had the thing for years by this time, with no problems. She came round, I let it rip, and it nearly blew the cones out of the speakers I was also selling her, with HUGE static DC offset out of both channels. As soon as I'd shat myself, I yanked the power and plugged another amp into the speakers. Luckily they were fine, but I measured the DC out of the Cyrus 2 at about 20V each side. So I sold her the speakers, which were fine ever since, but had to apologise for the unbelievably Sod's-law-esque failure of the amp, and she bought one elsewhere. Days or weeks later, I decided to give it another go with a multimeter on the outputs. No offset. Plugged in speakers - fine again. Obviously my "damp" cleaning cloth had been a bit more than damp, and dripped water into the amp, causing the offset temporarily. I'm still using the same amp now! Martin |
#3
Posted to sci.electronics.repair,uk.rec.audio
|
|||
|
|||
Mission amp schematics ...
"Fleetie" wrote in message ... Arfa Daily wrote: Anyone by any chance got a set of schematics for a Mission Cyrus amp to hand ? It has a small DC offset on one channel. Not large, but enough for the protect circuitry to see it as a problem. Unfortunately, I am seeing lots of tantalum bead caps in it ... :-( Arfa No, but I did have an alarming offset incident with my Cyrus 2 about 5 years ago. I was about to sell it to this girl I knew, so I got out a damp cloth, and gave the top and sides a good rubbing to remove the dust, before she came round. I'd had the thing for years by this time, with no problems. She came round, I let it rip, and it nearly blew the cones out of the speakers I was also selling her, with HUGE static DC offset out of both channels. As soon as I'd shat myself, I yanked the power and plugged another amp into the speakers. Luckily they were fine, but I measured the DC out of the Cyrus 2 at about 20V each side. So I sold her the speakers, which were fine ever since, but had to apologise for the unbelievably Sod's-law-esque failure of the amp, and she bought one elsewhere. Days or weeks later, I decided to give it another go with a multimeter on the outputs. No offset. Plugged in speakers - fine again. Obviously my "damp" cleaning cloth had been a bit more than damp, and dripped water into the amp, causing the offset temporarily. I'm still using the same amp now! Martin Hey Fleetie - long time no hear ! Trust you are well ? Would that this bloody amp was a simple as that ... The guy owns two of 'em. I had the other one in a few months back. It was making nasty howly farty noises due to a bunch of 'afterthought' electros glued across the rail reg ICs on the back of the board, all of which were bulging ready to burst. New caps fixed that, and it was fine for a couple of months, then it came back with an intermittent rustly crackle. That turned out to be o/p tr's on that channel. Now I have his other one failing to fully power with the status LED flashing forlornly. There is an offset of about -3v max on one channel. You can follow it back at least as far as the pre-driver stages by eye, but after that ... ?? Hence the need for a schematic. Ah well, I guess that one goes to the back of the bench for now :-) Arfa |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Mission Furniture | Woodworking | |||
Shaker and Mission? | Woodworking | |||
MISSION HEADBOARD | Woodworking | |||
2300+Monitor Schematics for Tech Engineers (August 2003) list Original UK schematics | Electronics Repair |